REVIEW Open Access

Ebola virus disease and critical illnessAleksandra Leligdowicz1 William A Fischer II2 Timothy M Uyeki3 Thomas E Fletcher45 Neill K J Adhikari16Gina Portella7 Francois Lamontagne8 Christophe Clement9 Shevin T Jacob10 Lewis Rubinson11Abel Vanderschuren12 Jan Hajek13 Srinivas Murthy14 Mauricio Ferri Ian Crozier15 Elhadj Ibrahima16Marie-Claire Lamah16 John S Schieffelin17 David Brett-Major18 Daniel G Bausch19 Nikki Shindo19Adrienne K Chan20 Tim OrsquoDempsey21 Sharmistha Mishra22 Michael Jacobs23 Stuart Dickson24G Marshall Lyon III25 and Robert A Fowler16

Abstract

As of 20 May 2016 there have been 28646 cases and 11323 deaths resulting from the West African Ebola virusdisease (EVD) outbreak reported to the World Health Organization There continue to be sporadic flare-ups of EVDcases in West AfricaEVD presentation is nonspecific and characterized initially by onset of fatigue myalgias arthralgias headache andfever this is followed several days later by anorexia nausea vomiting diarrhea and abdominal pain Anorexia andgastrointestinal losses lead to dehydration electrolyte abnormalities and metabolic acidosis and in some patientsacute kidney injury Hypoxia and ventilation failure occurs most often with severe illness and may be exacerbatedby substantial fluid requirements for intravascular volume repletion and some degree of systemic capillary leakAlthough minor bleeding manifestations are common hypovolemic and septic shock complicated by multisystemorgan dysfunction appear the most frequent causes of deathMales and females have been equally affected with children (0ndash14 years of age) accounting for 19 young adults(15ndash44 years) 58 and older adults (ge45 years) 23 of reported cases While the current case fatality proportionin West Africa is approximately 40 it has varied substantially over time (highest near the outbreak onset)according to available resources (40ndash90 mortality in West Africa compared to under 20 in Western Europe andthe USA) by age (near universal among neonates and high among older adults) and by Ebola viral load atadmissionWhile there is no Ebola virus-specific therapy proven to be effective in clinical trials mortality has been dramaticallylower among EVD patients managed with supportive intensive care in highly resourced settings allowing for theavoidance of hypovolemia correction of electrolyte and metabolic abnormalities and the provision of oxygenventilation vasopressors and dialysis when indicated This experience emphasizes that in addition to evaluatingspecific medical treatments improving the global capacity to provide supportive critical care to patients with EVDmay be the greatest opportunity to improve patient outcomes

Keywords Ebola Critical care

Correspondence robfowlersunnybrookca1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON CanadaFull list of author information is available at the end of the article

copy 2016 Leligdowicz et al Open Access This article is distributed under the terms of the Creative Commons Attribution 40International License (httpcreativecommonsorglicensesby40) which permits unrestricted use distribution andreproduction in any medium provided you give appropriate credit to the original author(s) and the source provide a link tothe Creative Commons license and indicate if changes were made The Creative Commons Public Domain Dedication waiver(httpcreativecommonsorgpublicdomainzero10) applies to the data made available in this article unless otherwise stated

Leligdowicz et al Critical Care (2016) 20217 DOI 101186s13054-016-1325-2

BackgroundIn December 2013 transmission of Zaire ebolavirus(Ebola virus (EBOV)) to humans occurred in southeasternGuinea [1] spreading to Liberia and Sierra Leone and rap-idly surpassing the cumulative total of previous Ebolavirus disease (EVD) outbreaks [2 3] Prior outbreaks oc-curred primarily in remote resource-challenged settingswith case fatality proportions of 50ndash88 [4] This currentoutbreak due to its size and spread in West Africa inaddition to exported and medically evacuated cases toEurope and North America has engaged a much broaderhealth worker community including critical care clini-cians While the clinical manifestations duration of ill-ness and transmissibility appear similar to previous EVDoutbreaks [1 5ndash9] with the availability and provision ofadvanced supportive care in Europe and North Americamortality was less than 20 emphasizing the potentialimportance of supportive and critical care in the manage-ment of EVD patients This review provides an up-to-dateexamination of EVD using the knowledge gained duringthe 2013ndash2016 West African outbreak to highlight rele-vance for the critical care physician

Viral hemorrhagic feversViral hemorrhagic fever describes the syndrome of acutesevere febrile illness caused by over 30 viruses from fourdifferent taxonomic familiesmdashFiloviridae ArenaviridaeBunyaviridae and Flaviviridae Although they differ indisease epidemiology transmission and pathogenesismost of these RNA viruses are zoonotic and cause non-specific symptoms including fever headache weaknessvomiting and diarrhea Infection with filoviruses includ-ing Marburg and Ebola viruses can be associated with arapid progression to hemodynamic instability shock andmultiorgan dysfunction [4 8]Filoviruses were discovered in 1967 when 31 labora-

tory workers became ill after coming into contact withgreen monkeys imported from Africa [10] The newlydiscovered virus killed 23 of infected workers in theGerman town of Marburg Ebola virus was discovered in1976 during simultaneous outbreaks in Zaire and Sudanin which 88 and 53 of patients died respectively[2 11 12] Since its discovery there have been approxi-mately 25 EVD outbreaks [3]

EpidemiologyThe West African EVD outbreak was first recognized inMarch 2014 in the forested region of southeasternGuinea However the first EVD case may have happenedas early as December 2013 with zoonotic transmissionof EBOV from an animal to a human and subsequenthuman-to-human spread [1] Transmission was likelywell underway throughout West Africa in the spring of2014 [13] By June 2014 there were a few hundred

confirmed or probable EVD cases 3000 by the end ofAugustmdashoutstripping the ability of providers at existingEbola treatment units to isolate and care for patientsmdashandeventually over 20000 cases by the end of December 2014[14] As of 20 May 2016 there have been 28610 reportedconfirmed probable and suspected EVD cases and 11308deaths in Guinea Sierra Leone and Liberia [15] Another 36cases have primarily received care in Mali Senegal andNigeria as well as countries outside Africa including theUSA UK Germany Spain France Italy the NetherlandsNorway and Switzerland (Table 1) (Additional file 1) EVDcases in West Africa have been reported equally amongmales and females with children (0ndash14 years of age)accounting for 19 young adults (15ndash44 years) 58 andolder adults (ge45 years) 23 of reported cases [5 6 16]

Characteristics of transmissionPerson-to-person transmission of EBOV occurs throughmucous membrane contact with bodily fluids (egvomit feces and blood) from those who are infectedand symptomatic or by touching the body of someonewho died of EVD [17] Droplet transmission is less likelyto occur due to low prevalence of respiratory symptoms[16 18] While there are animal transmission models ofaerosolized EBOV [19 20] the clinical relevance of smallparticle droplet nuclei transmission is unclear and mayonly apply to the care of critically ill patients undergoingaerosol-generating procedures (intubation and ventilationbronchoscopy) [18] Percutaneous transmission withsharps (needle-stick glass-related exposure) contaminatedwith infected bodily fluids is thought to be a very efficientmechanism of Ebola virus transmission [11]

Infection prevention and control practicesThe concern about EBOV transmission has positionedinfection prevention and control (IPC) at the center ofclinical care Theoretically meticulous provision of con-tact precautions (hand washing the use of gloves and agown along with protection against mucus membrane(eyes nose and mouth) exposure and proper donningand doffing of all personal protective equipment (PPE))should be sufficient to prevent nosocomial EBOV trans-mission In nonclimate-controlled West African Ebolatreatment facilities (Fig 1) the heat and humidity pre-vent optimal functioning of medical masks and someduckbill N-95 respirators (humidity and sweat causethem to sag and collapse) Tight fitting goggles oftenfog reducing visibility Face shields afford improved visi-bility but must provide sufficient coverage without riskof splash-related facial exposure Half-sphere semi-rigidrespirators tend to be more resistant to moisture-relatedcollapse and deformation However concern about thehigh mortality of EVD has led to IPC and PPE choicesin the field that sometimes do not follow traditional

Leligdowicz et al Critical Care (2016) 20217 Page 2 of 14

infection control recommendations or guidance frominternational technical organizations This has often re-sulted in PPE that cannot be safely tolerated by healthcarepersonnel for more than 45ndash60 min due to excessive heatand humidity [21] risking syncope potentially dangerousbehaviour (eg adjusting fogged facial protection withsoiled gloves) and inability to safely perform tasks such asinsertion of intravenous catheters In West Africa Ebolavirus transmission likely also occurs among healthcarepersonnel during informal healthcare provision in the com-munity to patients or colleagues without appropriate infec-tion prevention and control practice [22 23] NosocomialEBOV transmission in Spain [24 25] and the USA [26]similarly reinforces the importance of rigorous Ebola IPCpractices and healthcare personnel training irrespective ofthe healthcare system [27 28]

Table 1 Chronological demographic description of 27 Ebola virus disease patients treated outside West Africa (August 2014ndashMay2015)

Age(years)

Occupation Country where Ebolavirus infection occurred

Case presentation Country of Hospitalisation Hospital LOS(days)

Outcome

1a 33 Health worker Liberia Medically evacuated USA 19 Survived

2a 59 Health worker Liberia Medically evacuated USA 14 Survived

3 75 Non health worker Liberia Medically evacuated Spain 5 Died

4 29 Health worker Sierra Leone Medically evacuated UK 10 Survived

5a 36 Health worker Sierra Leone Medically evacuated Germany 30 Survived

6a 51 Health worker Liberia Medically evacuated USA 20 Survived

7a 43 Health worker Sierra Leone Medically evacuated USA 41 Survived

8 NA Health worker Liberia Medically evacuated France 16 Survived

9 70 Nonhealth worker Sierra Leone Medically evacuated Spain 3 Died

10a 45 Unknown Liberia Imported infection USA 8 Died

11a 38 Health worker Sierra Leone Medically evacuated Germany 47 Survived

12a 44 Health worker Spain Secondary infection Spain 30 Survived

13a 33 Nonhealth worker Liberia Medically evacuated USA 16 Survived

14 30 Health worker Sierra Leone Medically evacuated Norway 13 Survived

15 56 Health worker Liberia Medically evacuated Germany 6 Died

16a 26 Health worker USA Secondary infection USA 13 Survived

17a 29 Health worker USA Secondary infection USA 14 Survived

18 33 Health worker Guinea Imported infection USA 19 Survived

19 NA Nonhealth worker Sierra Leone Medically evacuated France 21 Survived

20a 44 Health worker Sierra Leone Medically evacuated USA 2 Died

21a 43 Health worker Sierra Leone Medically evacuated Switzerland 15 Survived

22 50 Health worker Sierra Leone Medically evacuated Italy 38 Survived

23 NA Nonhealth worker Liberia Medically evacuated Netherlands 13 Survived

24 39 Health worker Sierra Leone Imported infection UK 25 Survived

25 25 Health worker Sierra Leone Medically evacuated UK 15 Survived

26 NA Health worker Sierra Leone Medically evacuated USA 27 Survived

27 NA Health worker Sierra Leone Imported infection Italy 31 SurvivedaMedical management (including utilization of invasive therapies) is described in peer-reviewed format (Table 3) and in reference [40]LOS length of stay (days) NA not available

Fig 1 West African Ebola Treatment FacilitymdashApril 2014

Leligdowicz et al Critical Care (2016) 20217 Page 3 of 14

PathophysiologyThe pathogenesis of EVD in humans remains poorlyunderstood but shows similarities with and differencesfrom other causes of viral hemorrhagic fever or bacterialsepsis End-organ dysfunction seems to result from acombination of a direct viral cytopathic effect the hostimmune response and from under-resuscitated hypovol-emic shock [5 6] EBOV binds to lectins and other surfacereceptors with monocytes macrophages and dendriticcells as targets These virus-containing cells spreadthrough the lymphatic system liver and spleen resultingin a widely disseminated viral infection [29 30] Endothe-lial cell infection and activation may lead to increasedlevels of soluble adhesion molecules thombomodulin andinflammatory mediators such as interferon-gamma and-alpha interleukins (IL)-2 6 and 10 interferon-inducibleproteins and tumor necrosis factor alpha [29 30] result-ing in vascular injuryThrombocytopenia consumption and reduced pro-

duction of clotting factors in addition to increasedconcentrations of fibrin degradation products in pa-tients with severe EVD may contribute to bleeding[29 30] Hepatocellular inflammation is common andmyositis with elevations of creatine kinase and pancreatitis(elevated blood amylase and lipase levels) occurs in severecases [29 30]While acute kidney injury can often be explained by

under-resuscitated hypovolemia it might also arisefrom viral or secondary bacterial sepsis acute tubularnecrosis myoglobinuria and microvascular renalthrombi associated with sepsis or disseminated intra-vascular coagulation [29 30] Adrenal gland viral infec-tion has been shown in animal models and mightcontribute to hypotension renal sodium loss andhypovolemia [30]

DiagnosticsDiagnostic testing is recommended when a patient ex-hibits symptoms meeting the EVD case definition [31]Ebola viral RNA can be detected in clinical specimensby real-time reverse transcription polymerase chain re-action (RT-PCR) if the virus is detected by a specificantigen diagnostic test or by detection of IgM anti-bodies directed against EBOV RT-PCR should be usedfor confirmation [31 32] Because the sensitivity of mo-lecular tests depends on Ebola viral loads specimenscollected within 3 days of symptom onset may befalsely negative due to undetectable viremia early in theclinical course In these circumstances another bloodspecimen for RT-PCR testing should be collected 3 daysafter symptom onset [33] Point-of-care rapid diagnos-tic tests (RDTs) have been tested in the field but theylack sensitivity require a cold chain and remain underevaluation in clinical trials [34]

Clinical presentation of Ebola virus diseaseThe clinical presentation of EVD falls along a spectrumranging from minimally symptomatic infection [8] to se-vere illness with hemorrhagic complications shock mul-tiorgan dysfunction and death The incubation periodranges from 2 to 21 days but may depend on the modeof transmission [4] 5ndash7 days following a percutaneousinoculation and a mean of 9 days following direct mucusmembrane contact with infected bodily fluids [8 30 35]EVD typically begins with nonspecific initial signs andsymptoms including fever fatigue weakness and head-ache similar to many infectious diseases in sub-SaharanAfrica often leading to a missed diagnosis and contin-ued transmission A fleeting maculopapular rash can beseen within the first week [36 37] Gastrointestinal symp-toms (nausea vomiting abdominal pain and diarrhea)usually follow 4ndash6 days after illness onset and can leadto hypovolemia and shock with multisystem organ dys-function Gastrointestinal losses and anorexia can precipi-tate hypokalemia metabolic acidosis and acute kidneyinjury [6] Hypoxia and ventilation failure tend to occurwith severe illness and may be exacerbated by vascular in-jury and accompanying large-volume fluid requirements[38] Serious hemorrhagic complications are relatively rarewhile more mild bleeding may occur in approximately 30 of cases [5 6 9 16 39 40] Delirium and encephalopathyor encephalitis may reflect metabolic encephalopathy ordirect neuroinvasion and hiccups may be of central or per-ipheral neurological origin [5 30 41 42]

Clinical outcomesWhile the cumulative case fatality proportion in WestAfrica is approximately 40 as of May 2016 it hasvaried substantially during the course of the outbreak(being higher near the beginning) In comparison thecumulative case fatality proportion for patients treatedin Western Europe and the USA during 2014ndash2015was 185 [40] (Table 2) Case fatality remains highestamong young children and older adults [5 6 16 43]Pregnant women often experience spontaneous abortion

Table 2 Demographic and outcome summary of 27 Ebola virusdisease patients treated outside West Africa

All Survived Died

Treated outside West Africa 27 22 (815 ) 5 (185 )

Gendera (male) 17 (68 ) 12 (60 ) 5 (100 )

Median ageb (range) 405 (25ndash75) 36 (25ndash59) 56 (42ndash75)

Mean hospital length of stay(days confidence interval)

19 (plusmn115) 22 (plusmn102) 5 (plusmn24)

Evacuated from West Africa 20 (74 ) 16 (80 ) 4 (20 )

Infected outside West Africa 3 (11 ) 3 (100 ) 0aGender available for 25 patientsbAge available for 22 patients

Leligdowicz et al Critical Care (2016) 20217 Page 4 of 14

followed by bleeding as well as preterm labor and still-birth if Ebola virus infection occurs later in pregnancyVertical transmission and subsequent neonatal mortalityhas been virtually uniform in the few documented livebirths by women with acute EVD [44] A high Ebola viralload at time of admission is associated with more severeillness and mortality [5 6 29 43 45ndash47] with othermarkers of organ dysfunction variably associated with out-comes [6 8 29 48]

Monitoring and care deliveryThe management of critically ill EVD patients in aresource-constrained setting has historically been re-stricted to variable monitoring of daily clinical signs andsymptoms without access to continuous assessment [8]The need for strict IPC practices and separation of pa-tient care areas in West Africa significantly limiteddocumentation and review of daily clinical records bothinside and outside of high-risk patient care As the caseburden decreased and the ratio of healthcare personnelto patients increased assessments were performed moresystematically at some Ebola treatment facilities withtemperature heart rate blood pressure respiratory ratepulse oximetry qualitative descriptions of urine andgastrointestinal output as well as fluid balance estimationLaboratory data other than Ebola RT-PCR results were

essentially unavailable at Ebola treatment facilities inWest Africa early in the outbreak [33 49 50] Initiallythere was very limited attention to diagnostics otherthan Ebola RT-PCR The point-of-care systems for mon-itoring biochemistry and hematology parameters suchas the i-STATreg or the Piccolo Xpressreg were inconsist-ently utilized inside Ebola treatment facilities [5 6 48]in part due to limited manufacturer-recommendedtemperature and humidity ranges Over the course ofthe West African outbreak with support from nationaland deployed international laboratories basic biochemis-try blood counts and coagulation profiles helped tocharacterize the course of illness but remained inconsist-ently available and often with substantial delays in resultsreporting due to transport and processing time Malariarapid diagnostic tests and less commonly RT-PCR wereavailable at most of the laboratories that supported Ebolatreatment facilities in West Africa However testing forLassa fever virus (endemic in EBOV-affected countries) orother causes of sepsis was not routineBedside ultrasonography has not been widely deployed

[51] but could help with assessing volume status responsive-ness to intravenous fluids [50] and assessment of challen-ging clinical signs such as abdominal distension [42] Plainchest and abdomen radiography has been performed inEuropean and North American settings [52] but has rarelybeen available to patients with Ebola in West AfricaAmong patients treated in the USA and Europe

pulmonary edema has been reported in 44 and acute re-spiratory distress syndrome in another 22 [40]

Discharge criteria and virus persistence duringconvalescenceThe World Health Organization (WHO) recommendsconsidering discharge of patients from isolation on thebasis of a negative blood Ebola virus RT-PCR resulttaken at least 3 days after the resolution of symptoms[33 41] However Ebola virus can persist in certain bodyfluids after it is undetectable in the blood and after clin-ical recovery from EVD [42 53ndash56] Viable Ebola virushas been isolated from urine semen cerebrospinal fluidand vitreous humor many months after blood clearance[42 56ndash61] suggesting that some activities (unprotectedsex invasive procedures or penetrating eye trauma)confer a transmission risk even after symptoms andviremia resolve It is therefore critical to counsel EVDsurvivors about the risks of Ebola virus persistence[59 60] and appropriate precautions after discharge in-cluding barrier protection during sexual intercourse [50]until semen has tested negative for Ebola virus twice orfor at least 6 months after EVD onset [62] Healthworkers and others should continue to apply standardprecautions as with all patients when evaluating EVDsurvivors in the convalescent period Additional infec-tion prevention and control practices based upon an in-dividual patient risk assessment may be prudent forspecific procedures in convalescence even when there isno detectable EBOV in the blood (eg lumbar punctureor vitreous humor sampling) [63]

Critical and supportive care interventionsProviding supportive care to critically ill patients withEVD in resource-poor settings is challenging [64] due tolimited infrastructure lack of materials and trainedhealthcare personnel and uncertainty regarding thetranslation of modern sepsis treatment strategies [65]and optimal intravenous fluid management protocols inthe absence of advanced monitoring used in resource-rich settings [66] Respiratory symptoms such as coughare not a prominent feature of EVD and tachypnea likelyrepresents respiratory compensation of severe metabolicacidosis [9 30 50] Translating fluid resuscitation proto-cols used in a resource-rich setting [42] to settingswhere supplemental oxygen therapy is not routinelyavailable [49] in a disease with possible vascular leaksyndrome [38] could result in increased morbidity [67]and warrants further investigation [68ndash70] The use ofantibiotics is common at Ebola treatment facilities [5 6]before the diagnosis of EVD is confirmed in febrilepatients and as empiric treatment of potential bacterialco-infection or gastrointestinal bacterial translocation inpatients with confirmed EVD [9] However disruption of

Leligdowicz et al Critical Care (2016) 20217 Page 5 of 14

gastrointestinal flora due to broad-spectrum antibioticscould exacerbate diarrhea and fluid losses Symptomatictreatment of severe diarrhea with loperamide was vari-ably employed across Ebola treatment facilities Therisks and benefits of these practices warrant evaluationwith observational studies and clinical trials [71]Early and during the peak of the outbreak clinical

management was generally limited to supportive care fo-cusing on aggressive oral and occasional intravenousvolume resuscitation As the case numbers decreasedadvanced care became more common in some treatmentfacilities Despite the limitations of working in PPEfeasibility and safety of central venous catheter placementwas demonstrated at a UK military-supported treatmentfacility in Kerry Town Sierra Leone [72] Feasibility oftransthoracic echocardiography was demonstrated at amilitary Ebola treatment facility in Conakry Guinea [51]By mid-December 2014 EMERGENCY an Italian non-governmental organization established an Ebola criticalcare unit in Lakka and Goderich Sierra Leone the latterconsisting of constant bedside nursing continuous bloodpressure heart rate respiratory rate monitoring pulseoximetry arterial and venous cannulation nasogastrictube feeding invasive ventilation continuous renal re-placement therapy diagnostic biochemistry andhematology ultrasonography and plain radiography(Fig 2) With waning case numbers accurate evaluationof the impact of these interventions on patient out-comes has not been possible Other sites such as theGOAL-supported Mathaska Ebola Treatment Unit (ETU)and the Partners in Health-supported Maforki ETU in Si-erra Leona also began using aspects of critical careprocedures by February 2015 including nasogastric tubefeeding bedside ultrasound as well as intraosseus cannu-lation for intravenous fluid resuscitation [73]The historical philosophy of providing only oral fluids

for EVD care has given way to the delivery of context-

appropriate critical care [38 42 74ndash79] To date 27 pa-tients managed in nine countries outside of West Africa(Table 1) have been described with a survival of 815 [40] (Table 2) Thirteen detailed accounts of EVD man-agement in modern healthcare settings in the USAGermany Spain and Switzerland provide insight intothe course of the illness [38 42 76ndash82] (Table 3) Thesecase reports confirm that intensive care monitoring inappropriately prepared centers is feasible Noninvasiveventilation [38 42] mechanical ventilation [38 78 81]central venous catheter insertion for vasopressor support[38 42 78 79 82] and renal replacement therapy[38 78 81 82] can be provided effectively and safely(Table 3 Figs 3 and 4) [83]

Establishing supportive and critical care servicesin highly resourced settingsWhile it may be advisable to concentrate or regionalizecare for patients with EVD in specific hospitals anyhealth centre should be prepared to safely take a focusedand relevant history from a patient with an infectioussyndrome and to mobilize the appropriate local and re-gional response Many hospitals even if not EVD refer-ral centers may be asked to care for patients until initial(and possibly subsequent) blood Ebola RT-PCR resultsare known Therefore it is essential that hospital staffare well trained and familiar with recommended IPCpractices (and for EVD standard and contact IPC pre-cautions in particular) It is ideal to have an on-callinter-professional team who have undergone training inEbola-specific IPC trainingWhile practiced IPC protocols are important to keep

health workers safe a very common clinical pitfall is toequate IPC practices with care While Ebola-specificstandardized IPC protocols are absolutely necessarythere will be situations requiring patient-specific IPCrisk-assessmentsmdashmost commonly involving patients atthe beginning of or in the convalescent phase of theirillness with minimal symptoms and no vomiting or diar-rhoea (ie with very low risk of transmission) It is alsoimportant to remember that most patients suspected withEVD will not have EVD but will have illness in need ofprompt treatmentmdashcommonly malariamdashthat may requireempiric treatment while awaiting diagnostic testing [8485] Barriers to providing the standard of care to patientssuspected of EVD will repeatedly arise ldquoWe donrsquot havethe capacity to do thathellip that is not part of our protocolrdquoDo not accept this when it negatively influences patientcare Instead ask collectively ldquoHow can we safely solve thischallenge now for the benefit of this patientrdquoFor hospitals and intensive care units (ICUs) that will

provide definitive care for patients with EVD there aremany Ebola-specific considerations well beyond the scopeof this review however a number deserve mention

Fig 2 Ebola treatment facility Goderich Sierra LeonemdashFebruary 2015

Leligdowicz et al Critical Care (2016) 20217 Page 6 of 14

Table 3 Clinical management summary of 13 Ebola virus disease patients treated outside West Africa

Reference [76] [76] [42] [28 79 137] [78 79 82] [81 82] [38] [25 77] [28 99] [81] [81] [82] [37]

Demographics

Gender M F M M M M M F M F F M M

Age (years) 33 59 36 51 43 42 38 44 33 26 29 44 43

Country ofinfection

Liberia Liberia Sierra Leone Liberia Sierra Leone Liberia Sierra Leone Spain Liberia USA USA Sierra Leone Sierra Leone

Countryproviding care

USA USA Germany USA USA USA Germany Spain USA USA USA USA Switzerland

Hospital admission

Admission date 2 Aug 2014 5 Aug 2014 27 Aug 2014 5 Sep 2014 9 Sep 2014 30 Sep 2014 3 Oct 2014 6 Oct 2014 6 Oct 2014 11 Oct 2014 14 Oct 2014 15 Nov 2014 21 Nov 2014

Days fromdiagnosis toevacuation

7 10 4 7 2 NA 5 0 5 NA NA 6 4

Hospital LOS 19 14 30 20 41 8 47 30 16 13 14 3 15

Vital status Survived Survived Survived Survived Survived Died Survived Survived Survived Survived Survived Died Survived

Critical care therapies

Central line N N Y Y Y Y Y N Y Y N Y Y

Vasopressors N N N N Y Y Y N N N N Y N

Oxygen Y Y Y Y Y Y Y Y N N N Y N

NIV (d days) N N Y (8d) N N N Y (1d) N N N N N N

MV (d days) N N N N Y (17d) Y (5d) Y (13d) N N N N Y (3d) N

CRRT (d days) N N N N Y (24d) Y (5d) Y (18d) N N N N Y (3d) N

IHD (d days) N N N N N N Y (10d) N N N N N N

Experimental therapies

Convalescentplasma

Y N N Y Y N N Y Y Y Y Y N

ZMappZMab Y Y N N N N N Y N Y N Y Y

Brincidofovir N N N N N Y N N Y Y Y N N

Favipiravir N N Y N N N Y Y N N N N Y

TKM N N Y Y Y N N N N Y N N N

Other NA NA NA NA NA NA AmiodaroneFX06

NA NA NA NA NA NA

CRRT continuous renal replacement therapy F female IHD intermittent hemodialysis LOS length of stay M male MV invasive mechanical ventilation NA not available NIV non-invasive ventilation TKM TKM-Ebolasmall interfering ribonucleic acids (siRNA) produced by Tekmira

Leligdowicz

etalCriticalCare

(2016) 20217 Page

7of

14

Hospitals and ICUs will generally need to mould EVDplanning to the local environment and seek out the ex-perience guidance protocols and training from thosewho have substantial clinical and operational experience(Figs 3 4) [64 86]Second the physical environment of a proposed Ebola

treatment unit is a critical component of care Ideally

there should be a large available physical space sufficientfor multiple isolation rooms with very generously sizedantechamber areas for donning and doffing and ashared area from where clinical observation can occur(Fig 4) There should be sufficient adjoining space tohouse dedicated diagnostic (eg portable radiograph andultrasound machines potentially point-of-care labora-tory devices) and therapeutic (intravenous pumps mech-anical ventilator and circuits dialysis machine andsupplies) equipment There should be ample nearbyspace to house packaged soiled PPE and medical wastethat allows pick-up and proper disposalThird is the necessity for sufficiently numerous and

trained inter-professional team of clinical (nurses physi-cians respiratory therapists others) and patient supportstaff (coordinators monitors cleaners patient transpor-tation services diagnostic and laboratory staff and soforth) who are well practiced in the institutional Ebolacare plan and their specific roles Whether this team isled by infectious disease or critical care specialists orboth is likely less important than establishing an inter-disciplinary model of continuity care throughout thehospital stay oftentimes in a single geographic locationthat is institutionally appropriateFourth while EVD is accompanied by an increasingly

well-characterized clinical gastrointestinal syndrome

Fig 3 Ebola treatment facility Royal Free Hospital LondonUKmdashSeptember 2014

Fig 4 Emory University Hospital special isolation unit (1) The private patient rooms resemble intensive acre unit rooms with adjustable bedsintravenous drips and monitors Every procedure a patient could need from mechanical ventilation to hemodialysis can be performed in the unit(2) Medical staff who are providing direct patient care use a locker room to change into full-body protective suits and masks which shield them fromblood and bodily fluids (3) Family members are able to speak with patients through glass windows in the unit patients have access to phones andlaptop computers (4) A dedicated lab was built specifically for the use with the isolation unit that has the capacity to perform blood counts routinechemistries blood gas measurements urinalysis and tests for a variety of infectious agents (5) All liquid waste is disinfected and flushedand disposable waste is autoclaved and incinerated At the peak of an Ebola patientrsquos illness up to 40 bags a day of medical waste were produced

Leligdowicz et al Critical Care (2016) 20217 Page 8 of 14

leading to fluid electrolyte and acid-base imbalancewith multisystem organ dysfunction there are no Ebola-specific therapies yet to be proven effective However in-tensive care medicine comprises experiential andevidence-based organ-supportive care which shouldguide the care of patients with EVDmdashattention to fluidelectrolyte and acid-base balance initiation of empiricand specific anti-infective therapy and support for renalinjury and respiratory failure as occurs for other poten-tially self-limited and survivable illnesses Among pa-tients with EVD treated in the USA and Europe 41 were deemed to have critical illness with 70 receivingsupplemental oxygen 22 with acute respiratory dis-tress syndrome 26 invasive mechanical ventilation30 intravenous vasoactive medications and 19 re-quiring dialysis [40]For the most severely ill patients clinical judgment is

always necessary to balance risks and benefits of certainresuscitation strategies including the initiation of car-diopulmonary resuscitation (CPR) [28 87] While thereis a lack of clinical experience with CPR in EVD pa-tients it may be a reasonable consideration while cor-recting reversible abnormalities (ie hypoxia severeelectrolyte disturbance arrhythmias) in settings wherethe option for advanced life-support exists The decisionto provide CPR should be guided by its medical indicationand utility in that context the ability to provide effectiveCPR and the safety of those providing care includingsafe donning and doffing of PPE in addition to patientpreferences [88 89]Fifth as with all critical illness medical technical care

is only one dimension of our support for patients andtheir families Patients with EVD and their families requiremechanisms to stay in audio and visual contact throughoutthe illnessmdashideally visual contact through transparent bar-riers or at safe distance or direct contact with superviseddonning and doffing of PPEmdashin addition to substantialpsychosocial support during and after EVD

Ebola-specific pharmacological prevention andtherapeuticsCurrent EVD treatment focuses on supportive care [70]as there are no specific treatment options yet to beproven effective [70 90 91] A number of Ebola-specifictreatment strategies have undergone preliminary clinicaltrial investigation including convalescent plasma Favi-piravir Brincidofovir and TMK-130803 [92ndash97] Trans-fusion of convalescent whole blood or plasma donatedby EVD survivors has been used in this and prior EVDoutbreaks [98] in an uncontrolled or compassionate-usebasis [25 79 81 99] and in animal models [100 101]One of three clinical trials of convalescent plasma ther-apy [94] has been completed and reported [102] In thisnonrandomized comparison to historical controls

transfusion of up to 500 ml convalescent plasma withunknown levels of neutralizing antibodies in 84 patientswith confirmed EVD was not associated with a signifi-cant improvement in survival While there were no ser-ious adverse reactions in this trial transfusion-relatedacute lung injury was described during convalescentplasma therapy in Spain [25] Favipiravir (ToyamaJapan) [103] a pre-existing influenza virus inhibitor hasbeen administered for compassionate use outside WestAfrica [37 38 42] In a multicenter nonrandomizedclinical trial in Guinea [104] 111 patients receiving Favi-piravir had similar survival to that based upon historicalcontrol patients The trial authors suggested that Favipir-avir should be further studied in patients with mediumto high viremia but not in those with very high viremia[105] Brincidofovir (Chimerix USA) a nucleotide ana-log that inhibits RNA-polymerase with in vitro activityagainst Ebola [106] was administered to a small numberof EVD patients for uncontrolled compassionate use[42 79 81 99] and was tested in a phase 2 clinical trialin Liberia [95] that was stopped after the manufacturerwithdrew study support [107] TKM-130803 is a formula-tion of lipid-nanoparticle-encapsulated small interferingribonucleic acids (siRNA) targeting two proteins involvedin Ebola virus transcription and replication (TekmiraUSA Canada) It was used in nonhuman primate Ebolavirus infection as a postexposure treatment strategy[108] and in patients medically evacuated from WestAfrica in uncontrolled compassionate use [79 81]However a phase 2 clinical trial (RAPIDE-TKM) inSierra Leone [96] was halted according to pre-establishedstopping rules [109]ZMapp a monoclonal antibody cocktail (Leafbio

USA) [110] has been used under the emergency investi-gational new drug approvals from the Food and DrugAdministration in patients treated in the USA WestAfrica and Western Europe [40 76 111] ZMapp treat-ment of rhesus macaques resulted in 100 survival evenwhen started 5 days after lethal EBOV infection [110] Inthe only randomized controlled trial of an investigationaltherapeutic for EVD ZMapp plus standard of care wascompared to standard of care alone for EVD patients infour countries including the three most impacted WestAfrican countries Due to the decline in EVD cases thisunblinded ZMapp randomized controlled trial onlyenrolled 72 of the prespecified target goal of 200 EVD pa-tients data were analyzed for 71 EVD patients and mor-tality in the ZMapp treatment group was 22 versus37 in the untreated group but this difference was notstatistically significant [112 113]The open-label uncontrolled and selected administra-

tion of other agents such as amiodarone [114] HMG-CoA reductase inhibitors and angiotensin II receptorantagonists [115] and therapies to counteract vascular

Leligdowicz et al Critical Care (2016) 20217 Page 9 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

infection control recommendations or guidance frominternational technical organizations This has often re-sulted in PPE that cannot be safely tolerated by healthcarepersonnel for more than 45ndash60 min due to excessive heatand humidity [21] risking syncope potentially dangerousbehaviour (eg adjusting fogged facial protection withsoiled gloves) and inability to safely perform tasks such asinsertion of intravenous catheters In West Africa Ebolavirus transmission likely also occurs among healthcarepersonnel during informal healthcare provision in the com-munity to patients or colleagues without appropriate infec-tion prevention and control practice [22 23] NosocomialEBOV transmission in Spain [24 25] and the USA [26]similarly reinforces the importance of rigorous Ebola IPCpractices and healthcare personnel training irrespective ofthe healthcare system [27 28]

Table 1 Chronological demographic description of 27 Ebola virus disease patients treated outside West Africa (August 2014ndashMay2015)

Age(years)

Occupation Country where Ebolavirus infection occurred

Case presentation Country of Hospitalisation Hospital LOS(days)

Outcome

1a 33 Health worker Liberia Medically evacuated USA 19 Survived

2a 59 Health worker Liberia Medically evacuated USA 14 Survived

3 75 Non health worker Liberia Medically evacuated Spain 5 Died

4 29 Health worker Sierra Leone Medically evacuated UK 10 Survived

5a 36 Health worker Sierra Leone Medically evacuated Germany 30 Survived

6a 51 Health worker Liberia Medically evacuated USA 20 Survived

7a 43 Health worker Sierra Leone Medically evacuated USA 41 Survived

8 NA Health worker Liberia Medically evacuated France 16 Survived

9 70 Nonhealth worker Sierra Leone Medically evacuated Spain 3 Died

10a 45 Unknown Liberia Imported infection USA 8 Died

11a 38 Health worker Sierra Leone Medically evacuated Germany 47 Survived

12a 44 Health worker Spain Secondary infection Spain 30 Survived

13a 33 Nonhealth worker Liberia Medically evacuated USA 16 Survived

14 30 Health worker Sierra Leone Medically evacuated Norway 13 Survived

15 56 Health worker Liberia Medically evacuated Germany 6 Died

16a 26 Health worker USA Secondary infection USA 13 Survived

17a 29 Health worker USA Secondary infection USA 14 Survived

18 33 Health worker Guinea Imported infection USA 19 Survived

19 NA Nonhealth worker Sierra Leone Medically evacuated France 21 Survived

20a 44 Health worker Sierra Leone Medically evacuated USA 2 Died

21a 43 Health worker Sierra Leone Medically evacuated Switzerland 15 Survived

22 50 Health worker Sierra Leone Medically evacuated Italy 38 Survived

23 NA Nonhealth worker Liberia Medically evacuated Netherlands 13 Survived

24 39 Health worker Sierra Leone Imported infection UK 25 Survived

25 25 Health worker Sierra Leone Medically evacuated UK 15 Survived

26 NA Health worker Sierra Leone Medically evacuated USA 27 Survived

27 NA Health worker Sierra Leone Imported infection Italy 31 SurvivedaMedical management (including utilization of invasive therapies) is described in peer-reviewed format (Table 3) and in reference [40]LOS length of stay (days) NA not available

Fig 1 West African Ebola Treatment FacilitymdashApril 2014

Leligdowicz et al Critical Care (2016) 20217 Page 3 of 14

PathophysiologyThe pathogenesis of EVD in humans remains poorlyunderstood but shows similarities with and differencesfrom other causes of viral hemorrhagic fever or bacterialsepsis End-organ dysfunction seems to result from acombination of a direct viral cytopathic effect the hostimmune response and from under-resuscitated hypovol-emic shock [5 6] EBOV binds to lectins and other surfacereceptors with monocytes macrophages and dendriticcells as targets These virus-containing cells spreadthrough the lymphatic system liver and spleen resultingin a widely disseminated viral infection [29 30] Endothe-lial cell infection and activation may lead to increasedlevels of soluble adhesion molecules thombomodulin andinflammatory mediators such as interferon-gamma and-alpha interleukins (IL)-2 6 and 10 interferon-inducibleproteins and tumor necrosis factor alpha [29 30] result-ing in vascular injuryThrombocytopenia consumption and reduced pro-

duction of clotting factors in addition to increasedconcentrations of fibrin degradation products in pa-tients with severe EVD may contribute to bleeding[29 30] Hepatocellular inflammation is common andmyositis with elevations of creatine kinase and pancreatitis(elevated blood amylase and lipase levels) occurs in severecases [29 30]While acute kidney injury can often be explained by

under-resuscitated hypovolemia it might also arisefrom viral or secondary bacterial sepsis acute tubularnecrosis myoglobinuria and microvascular renalthrombi associated with sepsis or disseminated intra-vascular coagulation [29 30] Adrenal gland viral infec-tion has been shown in animal models and mightcontribute to hypotension renal sodium loss andhypovolemia [30]

DiagnosticsDiagnostic testing is recommended when a patient ex-hibits symptoms meeting the EVD case definition [31]Ebola viral RNA can be detected in clinical specimensby real-time reverse transcription polymerase chain re-action (RT-PCR) if the virus is detected by a specificantigen diagnostic test or by detection of IgM anti-bodies directed against EBOV RT-PCR should be usedfor confirmation [31 32] Because the sensitivity of mo-lecular tests depends on Ebola viral loads specimenscollected within 3 days of symptom onset may befalsely negative due to undetectable viremia early in theclinical course In these circumstances another bloodspecimen for RT-PCR testing should be collected 3 daysafter symptom onset [33] Point-of-care rapid diagnos-tic tests (RDTs) have been tested in the field but theylack sensitivity require a cold chain and remain underevaluation in clinical trials [34]

Clinical presentation of Ebola virus diseaseThe clinical presentation of EVD falls along a spectrumranging from minimally symptomatic infection [8] to se-vere illness with hemorrhagic complications shock mul-tiorgan dysfunction and death The incubation periodranges from 2 to 21 days but may depend on the modeof transmission [4] 5ndash7 days following a percutaneousinoculation and a mean of 9 days following direct mucusmembrane contact with infected bodily fluids [8 30 35]EVD typically begins with nonspecific initial signs andsymptoms including fever fatigue weakness and head-ache similar to many infectious diseases in sub-SaharanAfrica often leading to a missed diagnosis and contin-ued transmission A fleeting maculopapular rash can beseen within the first week [36 37] Gastrointestinal symp-toms (nausea vomiting abdominal pain and diarrhea)usually follow 4ndash6 days after illness onset and can leadto hypovolemia and shock with multisystem organ dys-function Gastrointestinal losses and anorexia can precipi-tate hypokalemia metabolic acidosis and acute kidneyinjury [6] Hypoxia and ventilation failure tend to occurwith severe illness and may be exacerbated by vascular in-jury and accompanying large-volume fluid requirements[38] Serious hemorrhagic complications are relatively rarewhile more mild bleeding may occur in approximately 30 of cases [5 6 9 16 39 40] Delirium and encephalopathyor encephalitis may reflect metabolic encephalopathy ordirect neuroinvasion and hiccups may be of central or per-ipheral neurological origin [5 30 41 42]

Clinical outcomesWhile the cumulative case fatality proportion in WestAfrica is approximately 40 as of May 2016 it hasvaried substantially during the course of the outbreak(being higher near the beginning) In comparison thecumulative case fatality proportion for patients treatedin Western Europe and the USA during 2014ndash2015was 185 [40] (Table 2) Case fatality remains highestamong young children and older adults [5 6 16 43]Pregnant women often experience spontaneous abortion

Table 2 Demographic and outcome summary of 27 Ebola virusdisease patients treated outside West Africa

All Survived Died

Treated outside West Africa 27 22 (815 ) 5 (185 )

Gendera (male) 17 (68 ) 12 (60 ) 5 (100 )

Median ageb (range) 405 (25ndash75) 36 (25ndash59) 56 (42ndash75)

Mean hospital length of stay(days confidence interval)

19 (plusmn115) 22 (plusmn102) 5 (plusmn24)

Evacuated from West Africa 20 (74 ) 16 (80 ) 4 (20 )

Infected outside West Africa 3 (11 ) 3 (100 ) 0aGender available for 25 patientsbAge available for 22 patients

Leligdowicz et al Critical Care (2016) 20217 Page 4 of 14

followed by bleeding as well as preterm labor and still-birth if Ebola virus infection occurs later in pregnancyVertical transmission and subsequent neonatal mortalityhas been virtually uniform in the few documented livebirths by women with acute EVD [44] A high Ebola viralload at time of admission is associated with more severeillness and mortality [5 6 29 43 45ndash47] with othermarkers of organ dysfunction variably associated with out-comes [6 8 29 48]

Monitoring and care deliveryThe management of critically ill EVD patients in aresource-constrained setting has historically been re-stricted to variable monitoring of daily clinical signs andsymptoms without access to continuous assessment [8]The need for strict IPC practices and separation of pa-tient care areas in West Africa significantly limiteddocumentation and review of daily clinical records bothinside and outside of high-risk patient care As the caseburden decreased and the ratio of healthcare personnelto patients increased assessments were performed moresystematically at some Ebola treatment facilities withtemperature heart rate blood pressure respiratory ratepulse oximetry qualitative descriptions of urine andgastrointestinal output as well as fluid balance estimationLaboratory data other than Ebola RT-PCR results were

essentially unavailable at Ebola treatment facilities inWest Africa early in the outbreak [33 49 50] Initiallythere was very limited attention to diagnostics otherthan Ebola RT-PCR The point-of-care systems for mon-itoring biochemistry and hematology parameters suchas the i-STATreg or the Piccolo Xpressreg were inconsist-ently utilized inside Ebola treatment facilities [5 6 48]in part due to limited manufacturer-recommendedtemperature and humidity ranges Over the course ofthe West African outbreak with support from nationaland deployed international laboratories basic biochemis-try blood counts and coagulation profiles helped tocharacterize the course of illness but remained inconsist-ently available and often with substantial delays in resultsreporting due to transport and processing time Malariarapid diagnostic tests and less commonly RT-PCR wereavailable at most of the laboratories that supported Ebolatreatment facilities in West Africa However testing forLassa fever virus (endemic in EBOV-affected countries) orother causes of sepsis was not routineBedside ultrasonography has not been widely deployed

[51] but could help with assessing volume status responsive-ness to intravenous fluids [50] and assessment of challen-ging clinical signs such as abdominal distension [42] Plainchest and abdomen radiography has been performed inEuropean and North American settings [52] but has rarelybeen available to patients with Ebola in West AfricaAmong patients treated in the USA and Europe

pulmonary edema has been reported in 44 and acute re-spiratory distress syndrome in another 22 [40]

Discharge criteria and virus persistence duringconvalescenceThe World Health Organization (WHO) recommendsconsidering discharge of patients from isolation on thebasis of a negative blood Ebola virus RT-PCR resulttaken at least 3 days after the resolution of symptoms[33 41] However Ebola virus can persist in certain bodyfluids after it is undetectable in the blood and after clin-ical recovery from EVD [42 53ndash56] Viable Ebola virushas been isolated from urine semen cerebrospinal fluidand vitreous humor many months after blood clearance[42 56ndash61] suggesting that some activities (unprotectedsex invasive procedures or penetrating eye trauma)confer a transmission risk even after symptoms andviremia resolve It is therefore critical to counsel EVDsurvivors about the risks of Ebola virus persistence[59 60] and appropriate precautions after discharge in-cluding barrier protection during sexual intercourse [50]until semen has tested negative for Ebola virus twice orfor at least 6 months after EVD onset [62] Healthworkers and others should continue to apply standardprecautions as with all patients when evaluating EVDsurvivors in the convalescent period Additional infec-tion prevention and control practices based upon an in-dividual patient risk assessment may be prudent forspecific procedures in convalescence even when there isno detectable EBOV in the blood (eg lumbar punctureor vitreous humor sampling) [63]

Critical and supportive care interventionsProviding supportive care to critically ill patients withEVD in resource-poor settings is challenging [64] due tolimited infrastructure lack of materials and trainedhealthcare personnel and uncertainty regarding thetranslation of modern sepsis treatment strategies [65]and optimal intravenous fluid management protocols inthe absence of advanced monitoring used in resource-rich settings [66] Respiratory symptoms such as coughare not a prominent feature of EVD and tachypnea likelyrepresents respiratory compensation of severe metabolicacidosis [9 30 50] Translating fluid resuscitation proto-cols used in a resource-rich setting [42] to settingswhere supplemental oxygen therapy is not routinelyavailable [49] in a disease with possible vascular leaksyndrome [38] could result in increased morbidity [67]and warrants further investigation [68ndash70] The use ofantibiotics is common at Ebola treatment facilities [5 6]before the diagnosis of EVD is confirmed in febrilepatients and as empiric treatment of potential bacterialco-infection or gastrointestinal bacterial translocation inpatients with confirmed EVD [9] However disruption of

Leligdowicz et al Critical Care (2016) 20217 Page 5 of 14

gastrointestinal flora due to broad-spectrum antibioticscould exacerbate diarrhea and fluid losses Symptomatictreatment of severe diarrhea with loperamide was vari-ably employed across Ebola treatment facilities Therisks and benefits of these practices warrant evaluationwith observational studies and clinical trials [71]Early and during the peak of the outbreak clinical

management was generally limited to supportive care fo-cusing on aggressive oral and occasional intravenousvolume resuscitation As the case numbers decreasedadvanced care became more common in some treatmentfacilities Despite the limitations of working in PPEfeasibility and safety of central venous catheter placementwas demonstrated at a UK military-supported treatmentfacility in Kerry Town Sierra Leone [72] Feasibility oftransthoracic echocardiography was demonstrated at amilitary Ebola treatment facility in Conakry Guinea [51]By mid-December 2014 EMERGENCY an Italian non-governmental organization established an Ebola criticalcare unit in Lakka and Goderich Sierra Leone the latterconsisting of constant bedside nursing continuous bloodpressure heart rate respiratory rate monitoring pulseoximetry arterial and venous cannulation nasogastrictube feeding invasive ventilation continuous renal re-placement therapy diagnostic biochemistry andhematology ultrasonography and plain radiography(Fig 2) With waning case numbers accurate evaluationof the impact of these interventions on patient out-comes has not been possible Other sites such as theGOAL-supported Mathaska Ebola Treatment Unit (ETU)and the Partners in Health-supported Maforki ETU in Si-erra Leona also began using aspects of critical careprocedures by February 2015 including nasogastric tubefeeding bedside ultrasound as well as intraosseus cannu-lation for intravenous fluid resuscitation [73]The historical philosophy of providing only oral fluids

for EVD care has given way to the delivery of context-

appropriate critical care [38 42 74ndash79] To date 27 pa-tients managed in nine countries outside of West Africa(Table 1) have been described with a survival of 815 [40] (Table 2) Thirteen detailed accounts of EVD man-agement in modern healthcare settings in the USAGermany Spain and Switzerland provide insight intothe course of the illness [38 42 76ndash82] (Table 3) Thesecase reports confirm that intensive care monitoring inappropriately prepared centers is feasible Noninvasiveventilation [38 42] mechanical ventilation [38 78 81]central venous catheter insertion for vasopressor support[38 42 78 79 82] and renal replacement therapy[38 78 81 82] can be provided effectively and safely(Table 3 Figs 3 and 4) [83]

Establishing supportive and critical care servicesin highly resourced settingsWhile it may be advisable to concentrate or regionalizecare for patients with EVD in specific hospitals anyhealth centre should be prepared to safely take a focusedand relevant history from a patient with an infectioussyndrome and to mobilize the appropriate local and re-gional response Many hospitals even if not EVD refer-ral centers may be asked to care for patients until initial(and possibly subsequent) blood Ebola RT-PCR resultsare known Therefore it is essential that hospital staffare well trained and familiar with recommended IPCpractices (and for EVD standard and contact IPC pre-cautions in particular) It is ideal to have an on-callinter-professional team who have undergone training inEbola-specific IPC trainingWhile practiced IPC protocols are important to keep

health workers safe a very common clinical pitfall is toequate IPC practices with care While Ebola-specificstandardized IPC protocols are absolutely necessarythere will be situations requiring patient-specific IPCrisk-assessmentsmdashmost commonly involving patients atthe beginning of or in the convalescent phase of theirillness with minimal symptoms and no vomiting or diar-rhoea (ie with very low risk of transmission) It is alsoimportant to remember that most patients suspected withEVD will not have EVD but will have illness in need ofprompt treatmentmdashcommonly malariamdashthat may requireempiric treatment while awaiting diagnostic testing [8485] Barriers to providing the standard of care to patientssuspected of EVD will repeatedly arise ldquoWe donrsquot havethe capacity to do thathellip that is not part of our protocolrdquoDo not accept this when it negatively influences patientcare Instead ask collectively ldquoHow can we safely solve thischallenge now for the benefit of this patientrdquoFor hospitals and intensive care units (ICUs) that will

provide definitive care for patients with EVD there aremany Ebola-specific considerations well beyond the scopeof this review however a number deserve mention

Fig 2 Ebola treatment facility Goderich Sierra LeonemdashFebruary 2015

Leligdowicz et al Critical Care (2016) 20217 Page 6 of 14

Table 3 Clinical management summary of 13 Ebola virus disease patients treated outside West Africa

Reference [76] [76] [42] [28 79 137] [78 79 82] [81 82] [38] [25 77] [28 99] [81] [81] [82] [37]

Demographics

Gender M F M M M M M F M F F M M

Age (years) 33 59 36 51 43 42 38 44 33 26 29 44 43

Country ofinfection

Liberia Liberia Sierra Leone Liberia Sierra Leone Liberia Sierra Leone Spain Liberia USA USA Sierra Leone Sierra Leone

Countryproviding care

USA USA Germany USA USA USA Germany Spain USA USA USA USA Switzerland

Hospital admission

Admission date 2 Aug 2014 5 Aug 2014 27 Aug 2014 5 Sep 2014 9 Sep 2014 30 Sep 2014 3 Oct 2014 6 Oct 2014 6 Oct 2014 11 Oct 2014 14 Oct 2014 15 Nov 2014 21 Nov 2014

Days fromdiagnosis toevacuation

7 10 4 7 2 NA 5 0 5 NA NA 6 4

Hospital LOS 19 14 30 20 41 8 47 30 16 13 14 3 15

Vital status Survived Survived Survived Survived Survived Died Survived Survived Survived Survived Survived Died Survived

Critical care therapies

Central line N N Y Y Y Y Y N Y Y N Y Y

Vasopressors N N N N Y Y Y N N N N Y N

Oxygen Y Y Y Y Y Y Y Y N N N Y N

NIV (d days) N N Y (8d) N N N Y (1d) N N N N N N

MV (d days) N N N N Y (17d) Y (5d) Y (13d) N N N N Y (3d) N

CRRT (d days) N N N N Y (24d) Y (5d) Y (18d) N N N N Y (3d) N

IHD (d days) N N N N N N Y (10d) N N N N N N

Experimental therapies

Convalescentplasma

Y N N Y Y N N Y Y Y Y Y N

ZMappZMab Y Y N N N N N Y N Y N Y Y

Brincidofovir N N N N N Y N N Y Y Y N N

Favipiravir N N Y N N N Y Y N N N N Y

TKM N N Y Y Y N N N N Y N N N

Other NA NA NA NA NA NA AmiodaroneFX06

NA NA NA NA NA NA

CRRT continuous renal replacement therapy F female IHD intermittent hemodialysis LOS length of stay M male MV invasive mechanical ventilation NA not available NIV non-invasive ventilation TKM TKM-Ebolasmall interfering ribonucleic acids (siRNA) produced by Tekmira

Leligdowicz

etalCriticalCare

(2016) 20217 Page

7of

14

Hospitals and ICUs will generally need to mould EVDplanning to the local environment and seek out the ex-perience guidance protocols and training from thosewho have substantial clinical and operational experience(Figs 3 4) [64 86]Second the physical environment of a proposed Ebola

treatment unit is a critical component of care Ideally

there should be a large available physical space sufficientfor multiple isolation rooms with very generously sizedantechamber areas for donning and doffing and ashared area from where clinical observation can occur(Fig 4) There should be sufficient adjoining space tohouse dedicated diagnostic (eg portable radiograph andultrasound machines potentially point-of-care labora-tory devices) and therapeutic (intravenous pumps mech-anical ventilator and circuits dialysis machine andsupplies) equipment There should be ample nearbyspace to house packaged soiled PPE and medical wastethat allows pick-up and proper disposalThird is the necessity for sufficiently numerous and

trained inter-professional team of clinical (nurses physi-cians respiratory therapists others) and patient supportstaff (coordinators monitors cleaners patient transpor-tation services diagnostic and laboratory staff and soforth) who are well practiced in the institutional Ebolacare plan and their specific roles Whether this team isled by infectious disease or critical care specialists orboth is likely less important than establishing an inter-disciplinary model of continuity care throughout thehospital stay oftentimes in a single geographic locationthat is institutionally appropriateFourth while EVD is accompanied by an increasingly

well-characterized clinical gastrointestinal syndrome

Fig 3 Ebola treatment facility Royal Free Hospital LondonUKmdashSeptember 2014

Fig 4 Emory University Hospital special isolation unit (1) The private patient rooms resemble intensive acre unit rooms with adjustable bedsintravenous drips and monitors Every procedure a patient could need from mechanical ventilation to hemodialysis can be performed in the unit(2) Medical staff who are providing direct patient care use a locker room to change into full-body protective suits and masks which shield them fromblood and bodily fluids (3) Family members are able to speak with patients through glass windows in the unit patients have access to phones andlaptop computers (4) A dedicated lab was built specifically for the use with the isolation unit that has the capacity to perform blood counts routinechemistries blood gas measurements urinalysis and tests for a variety of infectious agents (5) All liquid waste is disinfected and flushedand disposable waste is autoclaved and incinerated At the peak of an Ebola patientrsquos illness up to 40 bags a day of medical waste were produced

Leligdowicz et al Critical Care (2016) 20217 Page 8 of 14

leading to fluid electrolyte and acid-base imbalancewith multisystem organ dysfunction there are no Ebola-specific therapies yet to be proven effective However in-tensive care medicine comprises experiential andevidence-based organ-supportive care which shouldguide the care of patients with EVDmdashattention to fluidelectrolyte and acid-base balance initiation of empiricand specific anti-infective therapy and support for renalinjury and respiratory failure as occurs for other poten-tially self-limited and survivable illnesses Among pa-tients with EVD treated in the USA and Europe 41 were deemed to have critical illness with 70 receivingsupplemental oxygen 22 with acute respiratory dis-tress syndrome 26 invasive mechanical ventilation30 intravenous vasoactive medications and 19 re-quiring dialysis [40]For the most severely ill patients clinical judgment is

always necessary to balance risks and benefits of certainresuscitation strategies including the initiation of car-diopulmonary resuscitation (CPR) [28 87] While thereis a lack of clinical experience with CPR in EVD pa-tients it may be a reasonable consideration while cor-recting reversible abnormalities (ie hypoxia severeelectrolyte disturbance arrhythmias) in settings wherethe option for advanced life-support exists The decisionto provide CPR should be guided by its medical indicationand utility in that context the ability to provide effectiveCPR and the safety of those providing care includingsafe donning and doffing of PPE in addition to patientpreferences [88 89]Fifth as with all critical illness medical technical care

is only one dimension of our support for patients andtheir families Patients with EVD and their families requiremechanisms to stay in audio and visual contact throughoutthe illnessmdashideally visual contact through transparent bar-riers or at safe distance or direct contact with superviseddonning and doffing of PPEmdashin addition to substantialpsychosocial support during and after EVD

Ebola-specific pharmacological prevention andtherapeuticsCurrent EVD treatment focuses on supportive care [70]as there are no specific treatment options yet to beproven effective [70 90 91] A number of Ebola-specifictreatment strategies have undergone preliminary clinicaltrial investigation including convalescent plasma Favi-piravir Brincidofovir and TMK-130803 [92ndash97] Trans-fusion of convalescent whole blood or plasma donatedby EVD survivors has been used in this and prior EVDoutbreaks [98] in an uncontrolled or compassionate-usebasis [25 79 81 99] and in animal models [100 101]One of three clinical trials of convalescent plasma ther-apy [94] has been completed and reported [102] In thisnonrandomized comparison to historical controls

transfusion of up to 500 ml convalescent plasma withunknown levels of neutralizing antibodies in 84 patientswith confirmed EVD was not associated with a signifi-cant improvement in survival While there were no ser-ious adverse reactions in this trial transfusion-relatedacute lung injury was described during convalescentplasma therapy in Spain [25] Favipiravir (ToyamaJapan) [103] a pre-existing influenza virus inhibitor hasbeen administered for compassionate use outside WestAfrica [37 38 42] In a multicenter nonrandomizedclinical trial in Guinea [104] 111 patients receiving Favi-piravir had similar survival to that based upon historicalcontrol patients The trial authors suggested that Favipir-avir should be further studied in patients with mediumto high viremia but not in those with very high viremia[105] Brincidofovir (Chimerix USA) a nucleotide ana-log that inhibits RNA-polymerase with in vitro activityagainst Ebola [106] was administered to a small numberof EVD patients for uncontrolled compassionate use[42 79 81 99] and was tested in a phase 2 clinical trialin Liberia [95] that was stopped after the manufacturerwithdrew study support [107] TKM-130803 is a formula-tion of lipid-nanoparticle-encapsulated small interferingribonucleic acids (siRNA) targeting two proteins involvedin Ebola virus transcription and replication (TekmiraUSA Canada) It was used in nonhuman primate Ebolavirus infection as a postexposure treatment strategy[108] and in patients medically evacuated from WestAfrica in uncontrolled compassionate use [79 81]However a phase 2 clinical trial (RAPIDE-TKM) inSierra Leone [96] was halted according to pre-establishedstopping rules [109]ZMapp a monoclonal antibody cocktail (Leafbio

USA) [110] has been used under the emergency investi-gational new drug approvals from the Food and DrugAdministration in patients treated in the USA WestAfrica and Western Europe [40 76 111] ZMapp treat-ment of rhesus macaques resulted in 100 survival evenwhen started 5 days after lethal EBOV infection [110] Inthe only randomized controlled trial of an investigationaltherapeutic for EVD ZMapp plus standard of care wascompared to standard of care alone for EVD patients infour countries including the three most impacted WestAfrican countries Due to the decline in EVD cases thisunblinded ZMapp randomized controlled trial onlyenrolled 72 of the prespecified target goal of 200 EVD pa-tients data were analyzed for 71 EVD patients and mor-tality in the ZMapp treatment group was 22 versus37 in the untreated group but this difference was notstatistically significant [112 113]The open-label uncontrolled and selected administra-

tion of other agents such as amiodarone [114] HMG-CoA reductase inhibitors and angiotensin II receptorantagonists [115] and therapies to counteract vascular

Leligdowicz et al Critical Care (2016) 20217 Page 9 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

PathophysiologyThe pathogenesis of EVD in humans remains poorlyunderstood but shows similarities with and differencesfrom other causes of viral hemorrhagic fever or bacterialsepsis End-organ dysfunction seems to result from acombination of a direct viral cytopathic effect the hostimmune response and from under-resuscitated hypovol-emic shock [5 6] EBOV binds to lectins and other surfacereceptors with monocytes macrophages and dendriticcells as targets These virus-containing cells spreadthrough the lymphatic system liver and spleen resultingin a widely disseminated viral infection [29 30] Endothe-lial cell infection and activation may lead to increasedlevels of soluble adhesion molecules thombomodulin andinflammatory mediators such as interferon-gamma and-alpha interleukins (IL)-2 6 and 10 interferon-inducibleproteins and tumor necrosis factor alpha [29 30] result-ing in vascular injuryThrombocytopenia consumption and reduced pro-

duction of clotting factors in addition to increasedconcentrations of fibrin degradation products in pa-tients with severe EVD may contribute to bleeding[29 30] Hepatocellular inflammation is common andmyositis with elevations of creatine kinase and pancreatitis(elevated blood amylase and lipase levels) occurs in severecases [29 30]While acute kidney injury can often be explained by

under-resuscitated hypovolemia it might also arisefrom viral or secondary bacterial sepsis acute tubularnecrosis myoglobinuria and microvascular renalthrombi associated with sepsis or disseminated intra-vascular coagulation [29 30] Adrenal gland viral infec-tion has been shown in animal models and mightcontribute to hypotension renal sodium loss andhypovolemia [30]

DiagnosticsDiagnostic testing is recommended when a patient ex-hibits symptoms meeting the EVD case definition [31]Ebola viral RNA can be detected in clinical specimensby real-time reverse transcription polymerase chain re-action (RT-PCR) if the virus is detected by a specificantigen diagnostic test or by detection of IgM anti-bodies directed against EBOV RT-PCR should be usedfor confirmation [31 32] Because the sensitivity of mo-lecular tests depends on Ebola viral loads specimenscollected within 3 days of symptom onset may befalsely negative due to undetectable viremia early in theclinical course In these circumstances another bloodspecimen for RT-PCR testing should be collected 3 daysafter symptom onset [33] Point-of-care rapid diagnos-tic tests (RDTs) have been tested in the field but theylack sensitivity require a cold chain and remain underevaluation in clinical trials [34]

Clinical presentation of Ebola virus diseaseThe clinical presentation of EVD falls along a spectrumranging from minimally symptomatic infection [8] to se-vere illness with hemorrhagic complications shock mul-tiorgan dysfunction and death The incubation periodranges from 2 to 21 days but may depend on the modeof transmission [4] 5ndash7 days following a percutaneousinoculation and a mean of 9 days following direct mucusmembrane contact with infected bodily fluids [8 30 35]EVD typically begins with nonspecific initial signs andsymptoms including fever fatigue weakness and head-ache similar to many infectious diseases in sub-SaharanAfrica often leading to a missed diagnosis and contin-ued transmission A fleeting maculopapular rash can beseen within the first week [36 37] Gastrointestinal symp-toms (nausea vomiting abdominal pain and diarrhea)usually follow 4ndash6 days after illness onset and can leadto hypovolemia and shock with multisystem organ dys-function Gastrointestinal losses and anorexia can precipi-tate hypokalemia metabolic acidosis and acute kidneyinjury [6] Hypoxia and ventilation failure tend to occurwith severe illness and may be exacerbated by vascular in-jury and accompanying large-volume fluid requirements[38] Serious hemorrhagic complications are relatively rarewhile more mild bleeding may occur in approximately 30 of cases [5 6 9 16 39 40] Delirium and encephalopathyor encephalitis may reflect metabolic encephalopathy ordirect neuroinvasion and hiccups may be of central or per-ipheral neurological origin [5 30 41 42]

Clinical outcomesWhile the cumulative case fatality proportion in WestAfrica is approximately 40 as of May 2016 it hasvaried substantially during the course of the outbreak(being higher near the beginning) In comparison thecumulative case fatality proportion for patients treatedin Western Europe and the USA during 2014ndash2015was 185 [40] (Table 2) Case fatality remains highestamong young children and older adults [5 6 16 43]Pregnant women often experience spontaneous abortion

Table 2 Demographic and outcome summary of 27 Ebola virusdisease patients treated outside West Africa

All Survived Died

Treated outside West Africa 27 22 (815 ) 5 (185 )

Gendera (male) 17 (68 ) 12 (60 ) 5 (100 )

Median ageb (range) 405 (25ndash75) 36 (25ndash59) 56 (42ndash75)

Mean hospital length of stay(days confidence interval)

19 (plusmn115) 22 (plusmn102) 5 (plusmn24)

Evacuated from West Africa 20 (74 ) 16 (80 ) 4 (20 )

Infected outside West Africa 3 (11 ) 3 (100 ) 0aGender available for 25 patientsbAge available for 22 patients

Leligdowicz et al Critical Care (2016) 20217 Page 4 of 14

followed by bleeding as well as preterm labor and still-birth if Ebola virus infection occurs later in pregnancyVertical transmission and subsequent neonatal mortalityhas been virtually uniform in the few documented livebirths by women with acute EVD [44] A high Ebola viralload at time of admission is associated with more severeillness and mortality [5 6 29 43 45ndash47] with othermarkers of organ dysfunction variably associated with out-comes [6 8 29 48]

Monitoring and care deliveryThe management of critically ill EVD patients in aresource-constrained setting has historically been re-stricted to variable monitoring of daily clinical signs andsymptoms without access to continuous assessment [8]The need for strict IPC practices and separation of pa-tient care areas in West Africa significantly limiteddocumentation and review of daily clinical records bothinside and outside of high-risk patient care As the caseburden decreased and the ratio of healthcare personnelto patients increased assessments were performed moresystematically at some Ebola treatment facilities withtemperature heart rate blood pressure respiratory ratepulse oximetry qualitative descriptions of urine andgastrointestinal output as well as fluid balance estimationLaboratory data other than Ebola RT-PCR results were

essentially unavailable at Ebola treatment facilities inWest Africa early in the outbreak [33 49 50] Initiallythere was very limited attention to diagnostics otherthan Ebola RT-PCR The point-of-care systems for mon-itoring biochemistry and hematology parameters suchas the i-STATreg or the Piccolo Xpressreg were inconsist-ently utilized inside Ebola treatment facilities [5 6 48]in part due to limited manufacturer-recommendedtemperature and humidity ranges Over the course ofthe West African outbreak with support from nationaland deployed international laboratories basic biochemis-try blood counts and coagulation profiles helped tocharacterize the course of illness but remained inconsist-ently available and often with substantial delays in resultsreporting due to transport and processing time Malariarapid diagnostic tests and less commonly RT-PCR wereavailable at most of the laboratories that supported Ebolatreatment facilities in West Africa However testing forLassa fever virus (endemic in EBOV-affected countries) orother causes of sepsis was not routineBedside ultrasonography has not been widely deployed

[51] but could help with assessing volume status responsive-ness to intravenous fluids [50] and assessment of challen-ging clinical signs such as abdominal distension [42] Plainchest and abdomen radiography has been performed inEuropean and North American settings [52] but has rarelybeen available to patients with Ebola in West AfricaAmong patients treated in the USA and Europe

pulmonary edema has been reported in 44 and acute re-spiratory distress syndrome in another 22 [40]

Discharge criteria and virus persistence duringconvalescenceThe World Health Organization (WHO) recommendsconsidering discharge of patients from isolation on thebasis of a negative blood Ebola virus RT-PCR resulttaken at least 3 days after the resolution of symptoms[33 41] However Ebola virus can persist in certain bodyfluids after it is undetectable in the blood and after clin-ical recovery from EVD [42 53ndash56] Viable Ebola virushas been isolated from urine semen cerebrospinal fluidand vitreous humor many months after blood clearance[42 56ndash61] suggesting that some activities (unprotectedsex invasive procedures or penetrating eye trauma)confer a transmission risk even after symptoms andviremia resolve It is therefore critical to counsel EVDsurvivors about the risks of Ebola virus persistence[59 60] and appropriate precautions after discharge in-cluding barrier protection during sexual intercourse [50]until semen has tested negative for Ebola virus twice orfor at least 6 months after EVD onset [62] Healthworkers and others should continue to apply standardprecautions as with all patients when evaluating EVDsurvivors in the convalescent period Additional infec-tion prevention and control practices based upon an in-dividual patient risk assessment may be prudent forspecific procedures in convalescence even when there isno detectable EBOV in the blood (eg lumbar punctureor vitreous humor sampling) [63]

Critical and supportive care interventionsProviding supportive care to critically ill patients withEVD in resource-poor settings is challenging [64] due tolimited infrastructure lack of materials and trainedhealthcare personnel and uncertainty regarding thetranslation of modern sepsis treatment strategies [65]and optimal intravenous fluid management protocols inthe absence of advanced monitoring used in resource-rich settings [66] Respiratory symptoms such as coughare not a prominent feature of EVD and tachypnea likelyrepresents respiratory compensation of severe metabolicacidosis [9 30 50] Translating fluid resuscitation proto-cols used in a resource-rich setting [42] to settingswhere supplemental oxygen therapy is not routinelyavailable [49] in a disease with possible vascular leaksyndrome [38] could result in increased morbidity [67]and warrants further investigation [68ndash70] The use ofantibiotics is common at Ebola treatment facilities [5 6]before the diagnosis of EVD is confirmed in febrilepatients and as empiric treatment of potential bacterialco-infection or gastrointestinal bacterial translocation inpatients with confirmed EVD [9] However disruption of

Leligdowicz et al Critical Care (2016) 20217 Page 5 of 14

gastrointestinal flora due to broad-spectrum antibioticscould exacerbate diarrhea and fluid losses Symptomatictreatment of severe diarrhea with loperamide was vari-ably employed across Ebola treatment facilities Therisks and benefits of these practices warrant evaluationwith observational studies and clinical trials [71]Early and during the peak of the outbreak clinical

management was generally limited to supportive care fo-cusing on aggressive oral and occasional intravenousvolume resuscitation As the case numbers decreasedadvanced care became more common in some treatmentfacilities Despite the limitations of working in PPEfeasibility and safety of central venous catheter placementwas demonstrated at a UK military-supported treatmentfacility in Kerry Town Sierra Leone [72] Feasibility oftransthoracic echocardiography was demonstrated at amilitary Ebola treatment facility in Conakry Guinea [51]By mid-December 2014 EMERGENCY an Italian non-governmental organization established an Ebola criticalcare unit in Lakka and Goderich Sierra Leone the latterconsisting of constant bedside nursing continuous bloodpressure heart rate respiratory rate monitoring pulseoximetry arterial and venous cannulation nasogastrictube feeding invasive ventilation continuous renal re-placement therapy diagnostic biochemistry andhematology ultrasonography and plain radiography(Fig 2) With waning case numbers accurate evaluationof the impact of these interventions on patient out-comes has not been possible Other sites such as theGOAL-supported Mathaska Ebola Treatment Unit (ETU)and the Partners in Health-supported Maforki ETU in Si-erra Leona also began using aspects of critical careprocedures by February 2015 including nasogastric tubefeeding bedside ultrasound as well as intraosseus cannu-lation for intravenous fluid resuscitation [73]The historical philosophy of providing only oral fluids

for EVD care has given way to the delivery of context-

appropriate critical care [38 42 74ndash79] To date 27 pa-tients managed in nine countries outside of West Africa(Table 1) have been described with a survival of 815 [40] (Table 2) Thirteen detailed accounts of EVD man-agement in modern healthcare settings in the USAGermany Spain and Switzerland provide insight intothe course of the illness [38 42 76ndash82] (Table 3) Thesecase reports confirm that intensive care monitoring inappropriately prepared centers is feasible Noninvasiveventilation [38 42] mechanical ventilation [38 78 81]central venous catheter insertion for vasopressor support[38 42 78 79 82] and renal replacement therapy[38 78 81 82] can be provided effectively and safely(Table 3 Figs 3 and 4) [83]

Establishing supportive and critical care servicesin highly resourced settingsWhile it may be advisable to concentrate or regionalizecare for patients with EVD in specific hospitals anyhealth centre should be prepared to safely take a focusedand relevant history from a patient with an infectioussyndrome and to mobilize the appropriate local and re-gional response Many hospitals even if not EVD refer-ral centers may be asked to care for patients until initial(and possibly subsequent) blood Ebola RT-PCR resultsare known Therefore it is essential that hospital staffare well trained and familiar with recommended IPCpractices (and for EVD standard and contact IPC pre-cautions in particular) It is ideal to have an on-callinter-professional team who have undergone training inEbola-specific IPC trainingWhile practiced IPC protocols are important to keep

health workers safe a very common clinical pitfall is toequate IPC practices with care While Ebola-specificstandardized IPC protocols are absolutely necessarythere will be situations requiring patient-specific IPCrisk-assessmentsmdashmost commonly involving patients atthe beginning of or in the convalescent phase of theirillness with minimal symptoms and no vomiting or diar-rhoea (ie with very low risk of transmission) It is alsoimportant to remember that most patients suspected withEVD will not have EVD but will have illness in need ofprompt treatmentmdashcommonly malariamdashthat may requireempiric treatment while awaiting diagnostic testing [8485] Barriers to providing the standard of care to patientssuspected of EVD will repeatedly arise ldquoWe donrsquot havethe capacity to do thathellip that is not part of our protocolrdquoDo not accept this when it negatively influences patientcare Instead ask collectively ldquoHow can we safely solve thischallenge now for the benefit of this patientrdquoFor hospitals and intensive care units (ICUs) that will

provide definitive care for patients with EVD there aremany Ebola-specific considerations well beyond the scopeof this review however a number deserve mention

Fig 2 Ebola treatment facility Goderich Sierra LeonemdashFebruary 2015

Leligdowicz et al Critical Care (2016) 20217 Page 6 of 14

Table 3 Clinical management summary of 13 Ebola virus disease patients treated outside West Africa

Reference [76] [76] [42] [28 79 137] [78 79 82] [81 82] [38] [25 77] [28 99] [81] [81] [82] [37]

Demographics

Gender M F M M M M M F M F F M M

Age (years) 33 59 36 51 43 42 38 44 33 26 29 44 43

Country ofinfection

Liberia Liberia Sierra Leone Liberia Sierra Leone Liberia Sierra Leone Spain Liberia USA USA Sierra Leone Sierra Leone

Countryproviding care

USA USA Germany USA USA USA Germany Spain USA USA USA USA Switzerland

Hospital admission

Admission date 2 Aug 2014 5 Aug 2014 27 Aug 2014 5 Sep 2014 9 Sep 2014 30 Sep 2014 3 Oct 2014 6 Oct 2014 6 Oct 2014 11 Oct 2014 14 Oct 2014 15 Nov 2014 21 Nov 2014

Days fromdiagnosis toevacuation

7 10 4 7 2 NA 5 0 5 NA NA 6 4

Hospital LOS 19 14 30 20 41 8 47 30 16 13 14 3 15

Vital status Survived Survived Survived Survived Survived Died Survived Survived Survived Survived Survived Died Survived

Critical care therapies

Central line N N Y Y Y Y Y N Y Y N Y Y

Vasopressors N N N N Y Y Y N N N N Y N

Oxygen Y Y Y Y Y Y Y Y N N N Y N

NIV (d days) N N Y (8d) N N N Y (1d) N N N N N N

MV (d days) N N N N Y (17d) Y (5d) Y (13d) N N N N Y (3d) N

CRRT (d days) N N N N Y (24d) Y (5d) Y (18d) N N N N Y (3d) N

IHD (d days) N N N N N N Y (10d) N N N N N N

Experimental therapies

Convalescentplasma

Y N N Y Y N N Y Y Y Y Y N

ZMappZMab Y Y N N N N N Y N Y N Y Y

Brincidofovir N N N N N Y N N Y Y Y N N

Favipiravir N N Y N N N Y Y N N N N Y

TKM N N Y Y Y N N N N Y N N N

Other NA NA NA NA NA NA AmiodaroneFX06

NA NA NA NA NA NA

CRRT continuous renal replacement therapy F female IHD intermittent hemodialysis LOS length of stay M male MV invasive mechanical ventilation NA not available NIV non-invasive ventilation TKM TKM-Ebolasmall interfering ribonucleic acids (siRNA) produced by Tekmira

Leligdowicz

etalCriticalCare

(2016) 20217 Page

7of

14

Hospitals and ICUs will generally need to mould EVDplanning to the local environment and seek out the ex-perience guidance protocols and training from thosewho have substantial clinical and operational experience(Figs 3 4) [64 86]Second the physical environment of a proposed Ebola

treatment unit is a critical component of care Ideally

there should be a large available physical space sufficientfor multiple isolation rooms with very generously sizedantechamber areas for donning and doffing and ashared area from where clinical observation can occur(Fig 4) There should be sufficient adjoining space tohouse dedicated diagnostic (eg portable radiograph andultrasound machines potentially point-of-care labora-tory devices) and therapeutic (intravenous pumps mech-anical ventilator and circuits dialysis machine andsupplies) equipment There should be ample nearbyspace to house packaged soiled PPE and medical wastethat allows pick-up and proper disposalThird is the necessity for sufficiently numerous and

trained inter-professional team of clinical (nurses physi-cians respiratory therapists others) and patient supportstaff (coordinators monitors cleaners patient transpor-tation services diagnostic and laboratory staff and soforth) who are well practiced in the institutional Ebolacare plan and their specific roles Whether this team isled by infectious disease or critical care specialists orboth is likely less important than establishing an inter-disciplinary model of continuity care throughout thehospital stay oftentimes in a single geographic locationthat is institutionally appropriateFourth while EVD is accompanied by an increasingly

well-characterized clinical gastrointestinal syndrome

Fig 3 Ebola treatment facility Royal Free Hospital LondonUKmdashSeptember 2014

Fig 4 Emory University Hospital special isolation unit (1) The private patient rooms resemble intensive acre unit rooms with adjustable bedsintravenous drips and monitors Every procedure a patient could need from mechanical ventilation to hemodialysis can be performed in the unit(2) Medical staff who are providing direct patient care use a locker room to change into full-body protective suits and masks which shield them fromblood and bodily fluids (3) Family members are able to speak with patients through glass windows in the unit patients have access to phones andlaptop computers (4) A dedicated lab was built specifically for the use with the isolation unit that has the capacity to perform blood counts routinechemistries blood gas measurements urinalysis and tests for a variety of infectious agents (5) All liquid waste is disinfected and flushedand disposable waste is autoclaved and incinerated At the peak of an Ebola patientrsquos illness up to 40 bags a day of medical waste were produced

Leligdowicz et al Critical Care (2016) 20217 Page 8 of 14

leading to fluid electrolyte and acid-base imbalancewith multisystem organ dysfunction there are no Ebola-specific therapies yet to be proven effective However in-tensive care medicine comprises experiential andevidence-based organ-supportive care which shouldguide the care of patients with EVDmdashattention to fluidelectrolyte and acid-base balance initiation of empiricand specific anti-infective therapy and support for renalinjury and respiratory failure as occurs for other poten-tially self-limited and survivable illnesses Among pa-tients with EVD treated in the USA and Europe 41 were deemed to have critical illness with 70 receivingsupplemental oxygen 22 with acute respiratory dis-tress syndrome 26 invasive mechanical ventilation30 intravenous vasoactive medications and 19 re-quiring dialysis [40]For the most severely ill patients clinical judgment is

always necessary to balance risks and benefits of certainresuscitation strategies including the initiation of car-diopulmonary resuscitation (CPR) [28 87] While thereis a lack of clinical experience with CPR in EVD pa-tients it may be a reasonable consideration while cor-recting reversible abnormalities (ie hypoxia severeelectrolyte disturbance arrhythmias) in settings wherethe option for advanced life-support exists The decisionto provide CPR should be guided by its medical indicationand utility in that context the ability to provide effectiveCPR and the safety of those providing care includingsafe donning and doffing of PPE in addition to patientpreferences [88 89]Fifth as with all critical illness medical technical care

is only one dimension of our support for patients andtheir families Patients with EVD and their families requiremechanisms to stay in audio and visual contact throughoutthe illnessmdashideally visual contact through transparent bar-riers or at safe distance or direct contact with superviseddonning and doffing of PPEmdashin addition to substantialpsychosocial support during and after EVD

Ebola-specific pharmacological prevention andtherapeuticsCurrent EVD treatment focuses on supportive care [70]as there are no specific treatment options yet to beproven effective [70 90 91] A number of Ebola-specifictreatment strategies have undergone preliminary clinicaltrial investigation including convalescent plasma Favi-piravir Brincidofovir and TMK-130803 [92ndash97] Trans-fusion of convalescent whole blood or plasma donatedby EVD survivors has been used in this and prior EVDoutbreaks [98] in an uncontrolled or compassionate-usebasis [25 79 81 99] and in animal models [100 101]One of three clinical trials of convalescent plasma ther-apy [94] has been completed and reported [102] In thisnonrandomized comparison to historical controls

transfusion of up to 500 ml convalescent plasma withunknown levels of neutralizing antibodies in 84 patientswith confirmed EVD was not associated with a signifi-cant improvement in survival While there were no ser-ious adverse reactions in this trial transfusion-relatedacute lung injury was described during convalescentplasma therapy in Spain [25] Favipiravir (ToyamaJapan) [103] a pre-existing influenza virus inhibitor hasbeen administered for compassionate use outside WestAfrica [37 38 42] In a multicenter nonrandomizedclinical trial in Guinea [104] 111 patients receiving Favi-piravir had similar survival to that based upon historicalcontrol patients The trial authors suggested that Favipir-avir should be further studied in patients with mediumto high viremia but not in those with very high viremia[105] Brincidofovir (Chimerix USA) a nucleotide ana-log that inhibits RNA-polymerase with in vitro activityagainst Ebola [106] was administered to a small numberof EVD patients for uncontrolled compassionate use[42 79 81 99] and was tested in a phase 2 clinical trialin Liberia [95] that was stopped after the manufacturerwithdrew study support [107] TKM-130803 is a formula-tion of lipid-nanoparticle-encapsulated small interferingribonucleic acids (siRNA) targeting two proteins involvedin Ebola virus transcription and replication (TekmiraUSA Canada) It was used in nonhuman primate Ebolavirus infection as a postexposure treatment strategy[108] and in patients medically evacuated from WestAfrica in uncontrolled compassionate use [79 81]However a phase 2 clinical trial (RAPIDE-TKM) inSierra Leone [96] was halted according to pre-establishedstopping rules [109]ZMapp a monoclonal antibody cocktail (Leafbio

USA) [110] has been used under the emergency investi-gational new drug approvals from the Food and DrugAdministration in patients treated in the USA WestAfrica and Western Europe [40 76 111] ZMapp treat-ment of rhesus macaques resulted in 100 survival evenwhen started 5 days after lethal EBOV infection [110] Inthe only randomized controlled trial of an investigationaltherapeutic for EVD ZMapp plus standard of care wascompared to standard of care alone for EVD patients infour countries including the three most impacted WestAfrican countries Due to the decline in EVD cases thisunblinded ZMapp randomized controlled trial onlyenrolled 72 of the prespecified target goal of 200 EVD pa-tients data were analyzed for 71 EVD patients and mor-tality in the ZMapp treatment group was 22 versus37 in the untreated group but this difference was notstatistically significant [112 113]The open-label uncontrolled and selected administra-

tion of other agents such as amiodarone [114] HMG-CoA reductase inhibitors and angiotensin II receptorantagonists [115] and therapies to counteract vascular

Leligdowicz et al Critical Care (2016) 20217 Page 9 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

followed by bleeding as well as preterm labor and still-birth if Ebola virus infection occurs later in pregnancyVertical transmission and subsequent neonatal mortalityhas been virtually uniform in the few documented livebirths by women with acute EVD [44] A high Ebola viralload at time of admission is associated with more severeillness and mortality [5 6 29 43 45ndash47] with othermarkers of organ dysfunction variably associated with out-comes [6 8 29 48]

Monitoring and care deliveryThe management of critically ill EVD patients in aresource-constrained setting has historically been re-stricted to variable monitoring of daily clinical signs andsymptoms without access to continuous assessment [8]The need for strict IPC practices and separation of pa-tient care areas in West Africa significantly limiteddocumentation and review of daily clinical records bothinside and outside of high-risk patient care As the caseburden decreased and the ratio of healthcare personnelto patients increased assessments were performed moresystematically at some Ebola treatment facilities withtemperature heart rate blood pressure respiratory ratepulse oximetry qualitative descriptions of urine andgastrointestinal output as well as fluid balance estimationLaboratory data other than Ebola RT-PCR results were

essentially unavailable at Ebola treatment facilities inWest Africa early in the outbreak [33 49 50] Initiallythere was very limited attention to diagnostics otherthan Ebola RT-PCR The point-of-care systems for mon-itoring biochemistry and hematology parameters suchas the i-STATreg or the Piccolo Xpressreg were inconsist-ently utilized inside Ebola treatment facilities [5 6 48]in part due to limited manufacturer-recommendedtemperature and humidity ranges Over the course ofthe West African outbreak with support from nationaland deployed international laboratories basic biochemis-try blood counts and coagulation profiles helped tocharacterize the course of illness but remained inconsist-ently available and often with substantial delays in resultsreporting due to transport and processing time Malariarapid diagnostic tests and less commonly RT-PCR wereavailable at most of the laboratories that supported Ebolatreatment facilities in West Africa However testing forLassa fever virus (endemic in EBOV-affected countries) orother causes of sepsis was not routineBedside ultrasonography has not been widely deployed

[51] but could help with assessing volume status responsive-ness to intravenous fluids [50] and assessment of challen-ging clinical signs such as abdominal distension [42] Plainchest and abdomen radiography has been performed inEuropean and North American settings [52] but has rarelybeen available to patients with Ebola in West AfricaAmong patients treated in the USA and Europe

pulmonary edema has been reported in 44 and acute re-spiratory distress syndrome in another 22 [40]

Discharge criteria and virus persistence duringconvalescenceThe World Health Organization (WHO) recommendsconsidering discharge of patients from isolation on thebasis of a negative blood Ebola virus RT-PCR resulttaken at least 3 days after the resolution of symptoms[33 41] However Ebola virus can persist in certain bodyfluids after it is undetectable in the blood and after clin-ical recovery from EVD [42 53ndash56] Viable Ebola virushas been isolated from urine semen cerebrospinal fluidand vitreous humor many months after blood clearance[42 56ndash61] suggesting that some activities (unprotectedsex invasive procedures or penetrating eye trauma)confer a transmission risk even after symptoms andviremia resolve It is therefore critical to counsel EVDsurvivors about the risks of Ebola virus persistence[59 60] and appropriate precautions after discharge in-cluding barrier protection during sexual intercourse [50]until semen has tested negative for Ebola virus twice orfor at least 6 months after EVD onset [62] Healthworkers and others should continue to apply standardprecautions as with all patients when evaluating EVDsurvivors in the convalescent period Additional infec-tion prevention and control practices based upon an in-dividual patient risk assessment may be prudent forspecific procedures in convalescence even when there isno detectable EBOV in the blood (eg lumbar punctureor vitreous humor sampling) [63]

Critical and supportive care interventionsProviding supportive care to critically ill patients withEVD in resource-poor settings is challenging [64] due tolimited infrastructure lack of materials and trainedhealthcare personnel and uncertainty regarding thetranslation of modern sepsis treatment strategies [65]and optimal intravenous fluid management protocols inthe absence of advanced monitoring used in resource-rich settings [66] Respiratory symptoms such as coughare not a prominent feature of EVD and tachypnea likelyrepresents respiratory compensation of severe metabolicacidosis [9 30 50] Translating fluid resuscitation proto-cols used in a resource-rich setting [42] to settingswhere supplemental oxygen therapy is not routinelyavailable [49] in a disease with possible vascular leaksyndrome [38] could result in increased morbidity [67]and warrants further investigation [68ndash70] The use ofantibiotics is common at Ebola treatment facilities [5 6]before the diagnosis of EVD is confirmed in febrilepatients and as empiric treatment of potential bacterialco-infection or gastrointestinal bacterial translocation inpatients with confirmed EVD [9] However disruption of

Leligdowicz et al Critical Care (2016) 20217 Page 5 of 14

gastrointestinal flora due to broad-spectrum antibioticscould exacerbate diarrhea and fluid losses Symptomatictreatment of severe diarrhea with loperamide was vari-ably employed across Ebola treatment facilities Therisks and benefits of these practices warrant evaluationwith observational studies and clinical trials [71]Early and during the peak of the outbreak clinical

management was generally limited to supportive care fo-cusing on aggressive oral and occasional intravenousvolume resuscitation As the case numbers decreasedadvanced care became more common in some treatmentfacilities Despite the limitations of working in PPEfeasibility and safety of central venous catheter placementwas demonstrated at a UK military-supported treatmentfacility in Kerry Town Sierra Leone [72] Feasibility oftransthoracic echocardiography was demonstrated at amilitary Ebola treatment facility in Conakry Guinea [51]By mid-December 2014 EMERGENCY an Italian non-governmental organization established an Ebola criticalcare unit in Lakka and Goderich Sierra Leone the latterconsisting of constant bedside nursing continuous bloodpressure heart rate respiratory rate monitoring pulseoximetry arterial and venous cannulation nasogastrictube feeding invasive ventilation continuous renal re-placement therapy diagnostic biochemistry andhematology ultrasonography and plain radiography(Fig 2) With waning case numbers accurate evaluationof the impact of these interventions on patient out-comes has not been possible Other sites such as theGOAL-supported Mathaska Ebola Treatment Unit (ETU)and the Partners in Health-supported Maforki ETU in Si-erra Leona also began using aspects of critical careprocedures by February 2015 including nasogastric tubefeeding bedside ultrasound as well as intraosseus cannu-lation for intravenous fluid resuscitation [73]The historical philosophy of providing only oral fluids

for EVD care has given way to the delivery of context-

appropriate critical care [38 42 74ndash79] To date 27 pa-tients managed in nine countries outside of West Africa(Table 1) have been described with a survival of 815 [40] (Table 2) Thirteen detailed accounts of EVD man-agement in modern healthcare settings in the USAGermany Spain and Switzerland provide insight intothe course of the illness [38 42 76ndash82] (Table 3) Thesecase reports confirm that intensive care monitoring inappropriately prepared centers is feasible Noninvasiveventilation [38 42] mechanical ventilation [38 78 81]central venous catheter insertion for vasopressor support[38 42 78 79 82] and renal replacement therapy[38 78 81 82] can be provided effectively and safely(Table 3 Figs 3 and 4) [83]

Establishing supportive and critical care servicesin highly resourced settingsWhile it may be advisable to concentrate or regionalizecare for patients with EVD in specific hospitals anyhealth centre should be prepared to safely take a focusedand relevant history from a patient with an infectioussyndrome and to mobilize the appropriate local and re-gional response Many hospitals even if not EVD refer-ral centers may be asked to care for patients until initial(and possibly subsequent) blood Ebola RT-PCR resultsare known Therefore it is essential that hospital staffare well trained and familiar with recommended IPCpractices (and for EVD standard and contact IPC pre-cautions in particular) It is ideal to have an on-callinter-professional team who have undergone training inEbola-specific IPC trainingWhile practiced IPC protocols are important to keep

health workers safe a very common clinical pitfall is toequate IPC practices with care While Ebola-specificstandardized IPC protocols are absolutely necessarythere will be situations requiring patient-specific IPCrisk-assessmentsmdashmost commonly involving patients atthe beginning of or in the convalescent phase of theirillness with minimal symptoms and no vomiting or diar-rhoea (ie with very low risk of transmission) It is alsoimportant to remember that most patients suspected withEVD will not have EVD but will have illness in need ofprompt treatmentmdashcommonly malariamdashthat may requireempiric treatment while awaiting diagnostic testing [8485] Barriers to providing the standard of care to patientssuspected of EVD will repeatedly arise ldquoWe donrsquot havethe capacity to do thathellip that is not part of our protocolrdquoDo not accept this when it negatively influences patientcare Instead ask collectively ldquoHow can we safely solve thischallenge now for the benefit of this patientrdquoFor hospitals and intensive care units (ICUs) that will

provide definitive care for patients with EVD there aremany Ebola-specific considerations well beyond the scopeof this review however a number deserve mention

Fig 2 Ebola treatment facility Goderich Sierra LeonemdashFebruary 2015

Leligdowicz et al Critical Care (2016) 20217 Page 6 of 14

Table 3 Clinical management summary of 13 Ebola virus disease patients treated outside West Africa

Reference [76] [76] [42] [28 79 137] [78 79 82] [81 82] [38] [25 77] [28 99] [81] [81] [82] [37]

Demographics

Gender M F M M M M M F M F F M M

Age (years) 33 59 36 51 43 42 38 44 33 26 29 44 43

Country ofinfection

Liberia Liberia Sierra Leone Liberia Sierra Leone Liberia Sierra Leone Spain Liberia USA USA Sierra Leone Sierra Leone

Countryproviding care

USA USA Germany USA USA USA Germany Spain USA USA USA USA Switzerland

Hospital admission

Admission date 2 Aug 2014 5 Aug 2014 27 Aug 2014 5 Sep 2014 9 Sep 2014 30 Sep 2014 3 Oct 2014 6 Oct 2014 6 Oct 2014 11 Oct 2014 14 Oct 2014 15 Nov 2014 21 Nov 2014

Days fromdiagnosis toevacuation

7 10 4 7 2 NA 5 0 5 NA NA 6 4

Hospital LOS 19 14 30 20 41 8 47 30 16 13 14 3 15

Vital status Survived Survived Survived Survived Survived Died Survived Survived Survived Survived Survived Died Survived

Critical care therapies

Central line N N Y Y Y Y Y N Y Y N Y Y

Vasopressors N N N N Y Y Y N N N N Y N

Oxygen Y Y Y Y Y Y Y Y N N N Y N

NIV (d days) N N Y (8d) N N N Y (1d) N N N N N N

MV (d days) N N N N Y (17d) Y (5d) Y (13d) N N N N Y (3d) N

CRRT (d days) N N N N Y (24d) Y (5d) Y (18d) N N N N Y (3d) N

IHD (d days) N N N N N N Y (10d) N N N N N N

Experimental therapies

Convalescentplasma

Y N N Y Y N N Y Y Y Y Y N

ZMappZMab Y Y N N N N N Y N Y N Y Y

Brincidofovir N N N N N Y N N Y Y Y N N

Favipiravir N N Y N N N Y Y N N N N Y

TKM N N Y Y Y N N N N Y N N N

Other NA NA NA NA NA NA AmiodaroneFX06

NA NA NA NA NA NA

CRRT continuous renal replacement therapy F female IHD intermittent hemodialysis LOS length of stay M male MV invasive mechanical ventilation NA not available NIV non-invasive ventilation TKM TKM-Ebolasmall interfering ribonucleic acids (siRNA) produced by Tekmira

Leligdowicz

etalCriticalCare

(2016) 20217 Page

7of

14

Hospitals and ICUs will generally need to mould EVDplanning to the local environment and seek out the ex-perience guidance protocols and training from thosewho have substantial clinical and operational experience(Figs 3 4) [64 86]Second the physical environment of a proposed Ebola

treatment unit is a critical component of care Ideally

there should be a large available physical space sufficientfor multiple isolation rooms with very generously sizedantechamber areas for donning and doffing and ashared area from where clinical observation can occur(Fig 4) There should be sufficient adjoining space tohouse dedicated diagnostic (eg portable radiograph andultrasound machines potentially point-of-care labora-tory devices) and therapeutic (intravenous pumps mech-anical ventilator and circuits dialysis machine andsupplies) equipment There should be ample nearbyspace to house packaged soiled PPE and medical wastethat allows pick-up and proper disposalThird is the necessity for sufficiently numerous and

trained inter-professional team of clinical (nurses physi-cians respiratory therapists others) and patient supportstaff (coordinators monitors cleaners patient transpor-tation services diagnostic and laboratory staff and soforth) who are well practiced in the institutional Ebolacare plan and their specific roles Whether this team isled by infectious disease or critical care specialists orboth is likely less important than establishing an inter-disciplinary model of continuity care throughout thehospital stay oftentimes in a single geographic locationthat is institutionally appropriateFourth while EVD is accompanied by an increasingly

well-characterized clinical gastrointestinal syndrome

Fig 3 Ebola treatment facility Royal Free Hospital LondonUKmdashSeptember 2014

Fig 4 Emory University Hospital special isolation unit (1) The private patient rooms resemble intensive acre unit rooms with adjustable bedsintravenous drips and monitors Every procedure a patient could need from mechanical ventilation to hemodialysis can be performed in the unit(2) Medical staff who are providing direct patient care use a locker room to change into full-body protective suits and masks which shield them fromblood and bodily fluids (3) Family members are able to speak with patients through glass windows in the unit patients have access to phones andlaptop computers (4) A dedicated lab was built specifically for the use with the isolation unit that has the capacity to perform blood counts routinechemistries blood gas measurements urinalysis and tests for a variety of infectious agents (5) All liquid waste is disinfected and flushedand disposable waste is autoclaved and incinerated At the peak of an Ebola patientrsquos illness up to 40 bags a day of medical waste were produced

Leligdowicz et al Critical Care (2016) 20217 Page 8 of 14

leading to fluid electrolyte and acid-base imbalancewith multisystem organ dysfunction there are no Ebola-specific therapies yet to be proven effective However in-tensive care medicine comprises experiential andevidence-based organ-supportive care which shouldguide the care of patients with EVDmdashattention to fluidelectrolyte and acid-base balance initiation of empiricand specific anti-infective therapy and support for renalinjury and respiratory failure as occurs for other poten-tially self-limited and survivable illnesses Among pa-tients with EVD treated in the USA and Europe 41 were deemed to have critical illness with 70 receivingsupplemental oxygen 22 with acute respiratory dis-tress syndrome 26 invasive mechanical ventilation30 intravenous vasoactive medications and 19 re-quiring dialysis [40]For the most severely ill patients clinical judgment is

always necessary to balance risks and benefits of certainresuscitation strategies including the initiation of car-diopulmonary resuscitation (CPR) [28 87] While thereis a lack of clinical experience with CPR in EVD pa-tients it may be a reasonable consideration while cor-recting reversible abnormalities (ie hypoxia severeelectrolyte disturbance arrhythmias) in settings wherethe option for advanced life-support exists The decisionto provide CPR should be guided by its medical indicationand utility in that context the ability to provide effectiveCPR and the safety of those providing care includingsafe donning and doffing of PPE in addition to patientpreferences [88 89]Fifth as with all critical illness medical technical care

is only one dimension of our support for patients andtheir families Patients with EVD and their families requiremechanisms to stay in audio and visual contact throughoutthe illnessmdashideally visual contact through transparent bar-riers or at safe distance or direct contact with superviseddonning and doffing of PPEmdashin addition to substantialpsychosocial support during and after EVD

Ebola-specific pharmacological prevention andtherapeuticsCurrent EVD treatment focuses on supportive care [70]as there are no specific treatment options yet to beproven effective [70 90 91] A number of Ebola-specifictreatment strategies have undergone preliminary clinicaltrial investigation including convalescent plasma Favi-piravir Brincidofovir and TMK-130803 [92ndash97] Trans-fusion of convalescent whole blood or plasma donatedby EVD survivors has been used in this and prior EVDoutbreaks [98] in an uncontrolled or compassionate-usebasis [25 79 81 99] and in animal models [100 101]One of three clinical trials of convalescent plasma ther-apy [94] has been completed and reported [102] In thisnonrandomized comparison to historical controls

transfusion of up to 500 ml convalescent plasma withunknown levels of neutralizing antibodies in 84 patientswith confirmed EVD was not associated with a signifi-cant improvement in survival While there were no ser-ious adverse reactions in this trial transfusion-relatedacute lung injury was described during convalescentplasma therapy in Spain [25] Favipiravir (ToyamaJapan) [103] a pre-existing influenza virus inhibitor hasbeen administered for compassionate use outside WestAfrica [37 38 42] In a multicenter nonrandomizedclinical trial in Guinea [104] 111 patients receiving Favi-piravir had similar survival to that based upon historicalcontrol patients The trial authors suggested that Favipir-avir should be further studied in patients with mediumto high viremia but not in those with very high viremia[105] Brincidofovir (Chimerix USA) a nucleotide ana-log that inhibits RNA-polymerase with in vitro activityagainst Ebola [106] was administered to a small numberof EVD patients for uncontrolled compassionate use[42 79 81 99] and was tested in a phase 2 clinical trialin Liberia [95] that was stopped after the manufacturerwithdrew study support [107] TKM-130803 is a formula-tion of lipid-nanoparticle-encapsulated small interferingribonucleic acids (siRNA) targeting two proteins involvedin Ebola virus transcription and replication (TekmiraUSA Canada) It was used in nonhuman primate Ebolavirus infection as a postexposure treatment strategy[108] and in patients medically evacuated from WestAfrica in uncontrolled compassionate use [79 81]However a phase 2 clinical trial (RAPIDE-TKM) inSierra Leone [96] was halted according to pre-establishedstopping rules [109]ZMapp a monoclonal antibody cocktail (Leafbio

USA) [110] has been used under the emergency investi-gational new drug approvals from the Food and DrugAdministration in patients treated in the USA WestAfrica and Western Europe [40 76 111] ZMapp treat-ment of rhesus macaques resulted in 100 survival evenwhen started 5 days after lethal EBOV infection [110] Inthe only randomized controlled trial of an investigationaltherapeutic for EVD ZMapp plus standard of care wascompared to standard of care alone for EVD patients infour countries including the three most impacted WestAfrican countries Due to the decline in EVD cases thisunblinded ZMapp randomized controlled trial onlyenrolled 72 of the prespecified target goal of 200 EVD pa-tients data were analyzed for 71 EVD patients and mor-tality in the ZMapp treatment group was 22 versus37 in the untreated group but this difference was notstatistically significant [112 113]The open-label uncontrolled and selected administra-

tion of other agents such as amiodarone [114] HMG-CoA reductase inhibitors and angiotensin II receptorantagonists [115] and therapies to counteract vascular

Leligdowicz et al Critical Care (2016) 20217 Page 9 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

gastrointestinal flora due to broad-spectrum antibioticscould exacerbate diarrhea and fluid losses Symptomatictreatment of severe diarrhea with loperamide was vari-ably employed across Ebola treatment facilities Therisks and benefits of these practices warrant evaluationwith observational studies and clinical trials [71]Early and during the peak of the outbreak clinical

management was generally limited to supportive care fo-cusing on aggressive oral and occasional intravenousvolume resuscitation As the case numbers decreasedadvanced care became more common in some treatmentfacilities Despite the limitations of working in PPEfeasibility and safety of central venous catheter placementwas demonstrated at a UK military-supported treatmentfacility in Kerry Town Sierra Leone [72] Feasibility oftransthoracic echocardiography was demonstrated at amilitary Ebola treatment facility in Conakry Guinea [51]By mid-December 2014 EMERGENCY an Italian non-governmental organization established an Ebola criticalcare unit in Lakka and Goderich Sierra Leone the latterconsisting of constant bedside nursing continuous bloodpressure heart rate respiratory rate monitoring pulseoximetry arterial and venous cannulation nasogastrictube feeding invasive ventilation continuous renal re-placement therapy diagnostic biochemistry andhematology ultrasonography and plain radiography(Fig 2) With waning case numbers accurate evaluationof the impact of these interventions on patient out-comes has not been possible Other sites such as theGOAL-supported Mathaska Ebola Treatment Unit (ETU)and the Partners in Health-supported Maforki ETU in Si-erra Leona also began using aspects of critical careprocedures by February 2015 including nasogastric tubefeeding bedside ultrasound as well as intraosseus cannu-lation for intravenous fluid resuscitation [73]The historical philosophy of providing only oral fluids

for EVD care has given way to the delivery of context-

appropriate critical care [38 42 74ndash79] To date 27 pa-tients managed in nine countries outside of West Africa(Table 1) have been described with a survival of 815 [40] (Table 2) Thirteen detailed accounts of EVD man-agement in modern healthcare settings in the USAGermany Spain and Switzerland provide insight intothe course of the illness [38 42 76ndash82] (Table 3) Thesecase reports confirm that intensive care monitoring inappropriately prepared centers is feasible Noninvasiveventilation [38 42] mechanical ventilation [38 78 81]central venous catheter insertion for vasopressor support[38 42 78 79 82] and renal replacement therapy[38 78 81 82] can be provided effectively and safely(Table 3 Figs 3 and 4) [83]

Establishing supportive and critical care servicesin highly resourced settingsWhile it may be advisable to concentrate or regionalizecare for patients with EVD in specific hospitals anyhealth centre should be prepared to safely take a focusedand relevant history from a patient with an infectioussyndrome and to mobilize the appropriate local and re-gional response Many hospitals even if not EVD refer-ral centers may be asked to care for patients until initial(and possibly subsequent) blood Ebola RT-PCR resultsare known Therefore it is essential that hospital staffare well trained and familiar with recommended IPCpractices (and for EVD standard and contact IPC pre-cautions in particular) It is ideal to have an on-callinter-professional team who have undergone training inEbola-specific IPC trainingWhile practiced IPC protocols are important to keep

health workers safe a very common clinical pitfall is toequate IPC practices with care While Ebola-specificstandardized IPC protocols are absolutely necessarythere will be situations requiring patient-specific IPCrisk-assessmentsmdashmost commonly involving patients atthe beginning of or in the convalescent phase of theirillness with minimal symptoms and no vomiting or diar-rhoea (ie with very low risk of transmission) It is alsoimportant to remember that most patients suspected withEVD will not have EVD but will have illness in need ofprompt treatmentmdashcommonly malariamdashthat may requireempiric treatment while awaiting diagnostic testing [8485] Barriers to providing the standard of care to patientssuspected of EVD will repeatedly arise ldquoWe donrsquot havethe capacity to do thathellip that is not part of our protocolrdquoDo not accept this when it negatively influences patientcare Instead ask collectively ldquoHow can we safely solve thischallenge now for the benefit of this patientrdquoFor hospitals and intensive care units (ICUs) that will

provide definitive care for patients with EVD there aremany Ebola-specific considerations well beyond the scopeof this review however a number deserve mention

Fig 2 Ebola treatment facility Goderich Sierra LeonemdashFebruary 2015

Leligdowicz et al Critical Care (2016) 20217 Page 6 of 14

Table 3 Clinical management summary of 13 Ebola virus disease patients treated outside West Africa

Reference [76] [76] [42] [28 79 137] [78 79 82] [81 82] [38] [25 77] [28 99] [81] [81] [82] [37]

Demographics

Gender M F M M M M M F M F F M M

Age (years) 33 59 36 51 43 42 38 44 33 26 29 44 43

Country ofinfection

Liberia Liberia Sierra Leone Liberia Sierra Leone Liberia Sierra Leone Spain Liberia USA USA Sierra Leone Sierra Leone

Countryproviding care

USA USA Germany USA USA USA Germany Spain USA USA USA USA Switzerland

Hospital admission

Admission date 2 Aug 2014 5 Aug 2014 27 Aug 2014 5 Sep 2014 9 Sep 2014 30 Sep 2014 3 Oct 2014 6 Oct 2014 6 Oct 2014 11 Oct 2014 14 Oct 2014 15 Nov 2014 21 Nov 2014

Days fromdiagnosis toevacuation

7 10 4 7 2 NA 5 0 5 NA NA 6 4

Hospital LOS 19 14 30 20 41 8 47 30 16 13 14 3 15

Vital status Survived Survived Survived Survived Survived Died Survived Survived Survived Survived Survived Died Survived

Critical care therapies

Central line N N Y Y Y Y Y N Y Y N Y Y

Vasopressors N N N N Y Y Y N N N N Y N

Oxygen Y Y Y Y Y Y Y Y N N N Y N

NIV (d days) N N Y (8d) N N N Y (1d) N N N N N N

MV (d days) N N N N Y (17d) Y (5d) Y (13d) N N N N Y (3d) N

CRRT (d days) N N N N Y (24d) Y (5d) Y (18d) N N N N Y (3d) N

IHD (d days) N N N N N N Y (10d) N N N N N N

Experimental therapies

Convalescentplasma

Y N N Y Y N N Y Y Y Y Y N

ZMappZMab Y Y N N N N N Y N Y N Y Y

Brincidofovir N N N N N Y N N Y Y Y N N

Favipiravir N N Y N N N Y Y N N N N Y

TKM N N Y Y Y N N N N Y N N N

Other NA NA NA NA NA NA AmiodaroneFX06

NA NA NA NA NA NA

CRRT continuous renal replacement therapy F female IHD intermittent hemodialysis LOS length of stay M male MV invasive mechanical ventilation NA not available NIV non-invasive ventilation TKM TKM-Ebolasmall interfering ribonucleic acids (siRNA) produced by Tekmira

Leligdowicz

etalCriticalCare

(2016) 20217 Page

7of

14

Hospitals and ICUs will generally need to mould EVDplanning to the local environment and seek out the ex-perience guidance protocols and training from thosewho have substantial clinical and operational experience(Figs 3 4) [64 86]Second the physical environment of a proposed Ebola

treatment unit is a critical component of care Ideally

there should be a large available physical space sufficientfor multiple isolation rooms with very generously sizedantechamber areas for donning and doffing and ashared area from where clinical observation can occur(Fig 4) There should be sufficient adjoining space tohouse dedicated diagnostic (eg portable radiograph andultrasound machines potentially point-of-care labora-tory devices) and therapeutic (intravenous pumps mech-anical ventilator and circuits dialysis machine andsupplies) equipment There should be ample nearbyspace to house packaged soiled PPE and medical wastethat allows pick-up and proper disposalThird is the necessity for sufficiently numerous and

trained inter-professional team of clinical (nurses physi-cians respiratory therapists others) and patient supportstaff (coordinators monitors cleaners patient transpor-tation services diagnostic and laboratory staff and soforth) who are well practiced in the institutional Ebolacare plan and their specific roles Whether this team isled by infectious disease or critical care specialists orboth is likely less important than establishing an inter-disciplinary model of continuity care throughout thehospital stay oftentimes in a single geographic locationthat is institutionally appropriateFourth while EVD is accompanied by an increasingly

well-characterized clinical gastrointestinal syndrome

Fig 3 Ebola treatment facility Royal Free Hospital LondonUKmdashSeptember 2014

Fig 4 Emory University Hospital special isolation unit (1) The private patient rooms resemble intensive acre unit rooms with adjustable bedsintravenous drips and monitors Every procedure a patient could need from mechanical ventilation to hemodialysis can be performed in the unit(2) Medical staff who are providing direct patient care use a locker room to change into full-body protective suits and masks which shield them fromblood and bodily fluids (3) Family members are able to speak with patients through glass windows in the unit patients have access to phones andlaptop computers (4) A dedicated lab was built specifically for the use with the isolation unit that has the capacity to perform blood counts routinechemistries blood gas measurements urinalysis and tests for a variety of infectious agents (5) All liquid waste is disinfected and flushedand disposable waste is autoclaved and incinerated At the peak of an Ebola patientrsquos illness up to 40 bags a day of medical waste were produced

Leligdowicz et al Critical Care (2016) 20217 Page 8 of 14

leading to fluid electrolyte and acid-base imbalancewith multisystem organ dysfunction there are no Ebola-specific therapies yet to be proven effective However in-tensive care medicine comprises experiential andevidence-based organ-supportive care which shouldguide the care of patients with EVDmdashattention to fluidelectrolyte and acid-base balance initiation of empiricand specific anti-infective therapy and support for renalinjury and respiratory failure as occurs for other poten-tially self-limited and survivable illnesses Among pa-tients with EVD treated in the USA and Europe 41 were deemed to have critical illness with 70 receivingsupplemental oxygen 22 with acute respiratory dis-tress syndrome 26 invasive mechanical ventilation30 intravenous vasoactive medications and 19 re-quiring dialysis [40]For the most severely ill patients clinical judgment is

always necessary to balance risks and benefits of certainresuscitation strategies including the initiation of car-diopulmonary resuscitation (CPR) [28 87] While thereis a lack of clinical experience with CPR in EVD pa-tients it may be a reasonable consideration while cor-recting reversible abnormalities (ie hypoxia severeelectrolyte disturbance arrhythmias) in settings wherethe option for advanced life-support exists The decisionto provide CPR should be guided by its medical indicationand utility in that context the ability to provide effectiveCPR and the safety of those providing care includingsafe donning and doffing of PPE in addition to patientpreferences [88 89]Fifth as with all critical illness medical technical care

is only one dimension of our support for patients andtheir families Patients with EVD and their families requiremechanisms to stay in audio and visual contact throughoutthe illnessmdashideally visual contact through transparent bar-riers or at safe distance or direct contact with superviseddonning and doffing of PPEmdashin addition to substantialpsychosocial support during and after EVD

Ebola-specific pharmacological prevention andtherapeuticsCurrent EVD treatment focuses on supportive care [70]as there are no specific treatment options yet to beproven effective [70 90 91] A number of Ebola-specifictreatment strategies have undergone preliminary clinicaltrial investigation including convalescent plasma Favi-piravir Brincidofovir and TMK-130803 [92ndash97] Trans-fusion of convalescent whole blood or plasma donatedby EVD survivors has been used in this and prior EVDoutbreaks [98] in an uncontrolled or compassionate-usebasis [25 79 81 99] and in animal models [100 101]One of three clinical trials of convalescent plasma ther-apy [94] has been completed and reported [102] In thisnonrandomized comparison to historical controls

transfusion of up to 500 ml convalescent plasma withunknown levels of neutralizing antibodies in 84 patientswith confirmed EVD was not associated with a signifi-cant improvement in survival While there were no ser-ious adverse reactions in this trial transfusion-relatedacute lung injury was described during convalescentplasma therapy in Spain [25] Favipiravir (ToyamaJapan) [103] a pre-existing influenza virus inhibitor hasbeen administered for compassionate use outside WestAfrica [37 38 42] In a multicenter nonrandomizedclinical trial in Guinea [104] 111 patients receiving Favi-piravir had similar survival to that based upon historicalcontrol patients The trial authors suggested that Favipir-avir should be further studied in patients with mediumto high viremia but not in those with very high viremia[105] Brincidofovir (Chimerix USA) a nucleotide ana-log that inhibits RNA-polymerase with in vitro activityagainst Ebola [106] was administered to a small numberof EVD patients for uncontrolled compassionate use[42 79 81 99] and was tested in a phase 2 clinical trialin Liberia [95] that was stopped after the manufacturerwithdrew study support [107] TKM-130803 is a formula-tion of lipid-nanoparticle-encapsulated small interferingribonucleic acids (siRNA) targeting two proteins involvedin Ebola virus transcription and replication (TekmiraUSA Canada) It was used in nonhuman primate Ebolavirus infection as a postexposure treatment strategy[108] and in patients medically evacuated from WestAfrica in uncontrolled compassionate use [79 81]However a phase 2 clinical trial (RAPIDE-TKM) inSierra Leone [96] was halted according to pre-establishedstopping rules [109]ZMapp a monoclonal antibody cocktail (Leafbio

USA) [110] has been used under the emergency investi-gational new drug approvals from the Food and DrugAdministration in patients treated in the USA WestAfrica and Western Europe [40 76 111] ZMapp treat-ment of rhesus macaques resulted in 100 survival evenwhen started 5 days after lethal EBOV infection [110] Inthe only randomized controlled trial of an investigationaltherapeutic for EVD ZMapp plus standard of care wascompared to standard of care alone for EVD patients infour countries including the three most impacted WestAfrican countries Due to the decline in EVD cases thisunblinded ZMapp randomized controlled trial onlyenrolled 72 of the prespecified target goal of 200 EVD pa-tients data were analyzed for 71 EVD patients and mor-tality in the ZMapp treatment group was 22 versus37 in the untreated group but this difference was notstatistically significant [112 113]The open-label uncontrolled and selected administra-

tion of other agents such as amiodarone [114] HMG-CoA reductase inhibitors and angiotensin II receptorantagonists [115] and therapies to counteract vascular

Leligdowicz et al Critical Care (2016) 20217 Page 9 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

Table 3 Clinical management summary of 13 Ebola virus disease patients treated outside West Africa

Reference [76] [76] [42] [28 79 137] [78 79 82] [81 82] [38] [25 77] [28 99] [81] [81] [82] [37]

Demographics

Gender M F M M M M M F M F F M M

Age (years) 33 59 36 51 43 42 38 44 33 26 29 44 43

Country ofinfection

Liberia Liberia Sierra Leone Liberia Sierra Leone Liberia Sierra Leone Spain Liberia USA USA Sierra Leone Sierra Leone

Countryproviding care

USA USA Germany USA USA USA Germany Spain USA USA USA USA Switzerland

Hospital admission

Admission date 2 Aug 2014 5 Aug 2014 27 Aug 2014 5 Sep 2014 9 Sep 2014 30 Sep 2014 3 Oct 2014 6 Oct 2014 6 Oct 2014 11 Oct 2014 14 Oct 2014 15 Nov 2014 21 Nov 2014

Days fromdiagnosis toevacuation

7 10 4 7 2 NA 5 0 5 NA NA 6 4

Hospital LOS 19 14 30 20 41 8 47 30 16 13 14 3 15

Vital status Survived Survived Survived Survived Survived Died Survived Survived Survived Survived Survived Died Survived

Critical care therapies

Central line N N Y Y Y Y Y N Y Y N Y Y

Vasopressors N N N N Y Y Y N N N N Y N

Oxygen Y Y Y Y Y Y Y Y N N N Y N

NIV (d days) N N Y (8d) N N N Y (1d) N N N N N N

MV (d days) N N N N Y (17d) Y (5d) Y (13d) N N N N Y (3d) N

CRRT (d days) N N N N Y (24d) Y (5d) Y (18d) N N N N Y (3d) N

IHD (d days) N N N N N N Y (10d) N N N N N N

Experimental therapies

Convalescentplasma

Y N N Y Y N N Y Y Y Y Y N

ZMappZMab Y Y N N N N N Y N Y N Y Y

Brincidofovir N N N N N Y N N Y Y Y N N

Favipiravir N N Y N N N Y Y N N N N Y

TKM N N Y Y Y N N N N Y N N N

Other NA NA NA NA NA NA AmiodaroneFX06

NA NA NA NA NA NA

CRRT continuous renal replacement therapy F female IHD intermittent hemodialysis LOS length of stay M male MV invasive mechanical ventilation NA not available NIV non-invasive ventilation TKM TKM-Ebolasmall interfering ribonucleic acids (siRNA) produced by Tekmira

Leligdowicz

etalCriticalCare

(2016) 20217 Page

7of

14

Hospitals and ICUs will generally need to mould EVDplanning to the local environment and seek out the ex-perience guidance protocols and training from thosewho have substantial clinical and operational experience(Figs 3 4) [64 86]Second the physical environment of a proposed Ebola

treatment unit is a critical component of care Ideally

there should be a large available physical space sufficientfor multiple isolation rooms with very generously sizedantechamber areas for donning and doffing and ashared area from where clinical observation can occur(Fig 4) There should be sufficient adjoining space tohouse dedicated diagnostic (eg portable radiograph andultrasound machines potentially point-of-care labora-tory devices) and therapeutic (intravenous pumps mech-anical ventilator and circuits dialysis machine andsupplies) equipment There should be ample nearbyspace to house packaged soiled PPE and medical wastethat allows pick-up and proper disposalThird is the necessity for sufficiently numerous and

trained inter-professional team of clinical (nurses physi-cians respiratory therapists others) and patient supportstaff (coordinators monitors cleaners patient transpor-tation services diagnostic and laboratory staff and soforth) who are well practiced in the institutional Ebolacare plan and their specific roles Whether this team isled by infectious disease or critical care specialists orboth is likely less important than establishing an inter-disciplinary model of continuity care throughout thehospital stay oftentimes in a single geographic locationthat is institutionally appropriateFourth while EVD is accompanied by an increasingly

well-characterized clinical gastrointestinal syndrome

Fig 3 Ebola treatment facility Royal Free Hospital LondonUKmdashSeptember 2014

Fig 4 Emory University Hospital special isolation unit (1) The private patient rooms resemble intensive acre unit rooms with adjustable bedsintravenous drips and monitors Every procedure a patient could need from mechanical ventilation to hemodialysis can be performed in the unit(2) Medical staff who are providing direct patient care use a locker room to change into full-body protective suits and masks which shield them fromblood and bodily fluids (3) Family members are able to speak with patients through glass windows in the unit patients have access to phones andlaptop computers (4) A dedicated lab was built specifically for the use with the isolation unit that has the capacity to perform blood counts routinechemistries blood gas measurements urinalysis and tests for a variety of infectious agents (5) All liquid waste is disinfected and flushedand disposable waste is autoclaved and incinerated At the peak of an Ebola patientrsquos illness up to 40 bags a day of medical waste were produced

Leligdowicz et al Critical Care (2016) 20217 Page 8 of 14

leading to fluid electrolyte and acid-base imbalancewith multisystem organ dysfunction there are no Ebola-specific therapies yet to be proven effective However in-tensive care medicine comprises experiential andevidence-based organ-supportive care which shouldguide the care of patients with EVDmdashattention to fluidelectrolyte and acid-base balance initiation of empiricand specific anti-infective therapy and support for renalinjury and respiratory failure as occurs for other poten-tially self-limited and survivable illnesses Among pa-tients with EVD treated in the USA and Europe 41 were deemed to have critical illness with 70 receivingsupplemental oxygen 22 with acute respiratory dis-tress syndrome 26 invasive mechanical ventilation30 intravenous vasoactive medications and 19 re-quiring dialysis [40]For the most severely ill patients clinical judgment is

always necessary to balance risks and benefits of certainresuscitation strategies including the initiation of car-diopulmonary resuscitation (CPR) [28 87] While thereis a lack of clinical experience with CPR in EVD pa-tients it may be a reasonable consideration while cor-recting reversible abnormalities (ie hypoxia severeelectrolyte disturbance arrhythmias) in settings wherethe option for advanced life-support exists The decisionto provide CPR should be guided by its medical indicationand utility in that context the ability to provide effectiveCPR and the safety of those providing care includingsafe donning and doffing of PPE in addition to patientpreferences [88 89]Fifth as with all critical illness medical technical care

is only one dimension of our support for patients andtheir families Patients with EVD and their families requiremechanisms to stay in audio and visual contact throughoutthe illnessmdashideally visual contact through transparent bar-riers or at safe distance or direct contact with superviseddonning and doffing of PPEmdashin addition to substantialpsychosocial support during and after EVD

Ebola-specific pharmacological prevention andtherapeuticsCurrent EVD treatment focuses on supportive care [70]as there are no specific treatment options yet to beproven effective [70 90 91] A number of Ebola-specifictreatment strategies have undergone preliminary clinicaltrial investigation including convalescent plasma Favi-piravir Brincidofovir and TMK-130803 [92ndash97] Trans-fusion of convalescent whole blood or plasma donatedby EVD survivors has been used in this and prior EVDoutbreaks [98] in an uncontrolled or compassionate-usebasis [25 79 81 99] and in animal models [100 101]One of three clinical trials of convalescent plasma ther-apy [94] has been completed and reported [102] In thisnonrandomized comparison to historical controls

transfusion of up to 500 ml convalescent plasma withunknown levels of neutralizing antibodies in 84 patientswith confirmed EVD was not associated with a signifi-cant improvement in survival While there were no ser-ious adverse reactions in this trial transfusion-relatedacute lung injury was described during convalescentplasma therapy in Spain [25] Favipiravir (ToyamaJapan) [103] a pre-existing influenza virus inhibitor hasbeen administered for compassionate use outside WestAfrica [37 38 42] In a multicenter nonrandomizedclinical trial in Guinea [104] 111 patients receiving Favi-piravir had similar survival to that based upon historicalcontrol patients The trial authors suggested that Favipir-avir should be further studied in patients with mediumto high viremia but not in those with very high viremia[105] Brincidofovir (Chimerix USA) a nucleotide ana-log that inhibits RNA-polymerase with in vitro activityagainst Ebola [106] was administered to a small numberof EVD patients for uncontrolled compassionate use[42 79 81 99] and was tested in a phase 2 clinical trialin Liberia [95] that was stopped after the manufacturerwithdrew study support [107] TKM-130803 is a formula-tion of lipid-nanoparticle-encapsulated small interferingribonucleic acids (siRNA) targeting two proteins involvedin Ebola virus transcription and replication (TekmiraUSA Canada) It was used in nonhuman primate Ebolavirus infection as a postexposure treatment strategy[108] and in patients medically evacuated from WestAfrica in uncontrolled compassionate use [79 81]However a phase 2 clinical trial (RAPIDE-TKM) inSierra Leone [96] was halted according to pre-establishedstopping rules [109]ZMapp a monoclonal antibody cocktail (Leafbio

USA) [110] has been used under the emergency investi-gational new drug approvals from the Food and DrugAdministration in patients treated in the USA WestAfrica and Western Europe [40 76 111] ZMapp treat-ment of rhesus macaques resulted in 100 survival evenwhen started 5 days after lethal EBOV infection [110] Inthe only randomized controlled trial of an investigationaltherapeutic for EVD ZMapp plus standard of care wascompared to standard of care alone for EVD patients infour countries including the three most impacted WestAfrican countries Due to the decline in EVD cases thisunblinded ZMapp randomized controlled trial onlyenrolled 72 of the prespecified target goal of 200 EVD pa-tients data were analyzed for 71 EVD patients and mor-tality in the ZMapp treatment group was 22 versus37 in the untreated group but this difference was notstatistically significant [112 113]The open-label uncontrolled and selected administra-

tion of other agents such as amiodarone [114] HMG-CoA reductase inhibitors and angiotensin II receptorantagonists [115] and therapies to counteract vascular

Leligdowicz et al Critical Care (2016) 20217 Page 9 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

Hospitals and ICUs will generally need to mould EVDplanning to the local environment and seek out the ex-perience guidance protocols and training from thosewho have substantial clinical and operational experience(Figs 3 4) [64 86]Second the physical environment of a proposed Ebola

treatment unit is a critical component of care Ideally

there should be a large available physical space sufficientfor multiple isolation rooms with very generously sizedantechamber areas for donning and doffing and ashared area from where clinical observation can occur(Fig 4) There should be sufficient adjoining space tohouse dedicated diagnostic (eg portable radiograph andultrasound machines potentially point-of-care labora-tory devices) and therapeutic (intravenous pumps mech-anical ventilator and circuits dialysis machine andsupplies) equipment There should be ample nearbyspace to house packaged soiled PPE and medical wastethat allows pick-up and proper disposalThird is the necessity for sufficiently numerous and

trained inter-professional team of clinical (nurses physi-cians respiratory therapists others) and patient supportstaff (coordinators monitors cleaners patient transpor-tation services diagnostic and laboratory staff and soforth) who are well practiced in the institutional Ebolacare plan and their specific roles Whether this team isled by infectious disease or critical care specialists orboth is likely less important than establishing an inter-disciplinary model of continuity care throughout thehospital stay oftentimes in a single geographic locationthat is institutionally appropriateFourth while EVD is accompanied by an increasingly

well-characterized clinical gastrointestinal syndrome

Fig 3 Ebola treatment facility Royal Free Hospital LondonUKmdashSeptember 2014

Fig 4 Emory University Hospital special isolation unit (1) The private patient rooms resemble intensive acre unit rooms with adjustable bedsintravenous drips and monitors Every procedure a patient could need from mechanical ventilation to hemodialysis can be performed in the unit(2) Medical staff who are providing direct patient care use a locker room to change into full-body protective suits and masks which shield them fromblood and bodily fluids (3) Family members are able to speak with patients through glass windows in the unit patients have access to phones andlaptop computers (4) A dedicated lab was built specifically for the use with the isolation unit that has the capacity to perform blood counts routinechemistries blood gas measurements urinalysis and tests for a variety of infectious agents (5) All liquid waste is disinfected and flushedand disposable waste is autoclaved and incinerated At the peak of an Ebola patientrsquos illness up to 40 bags a day of medical waste were produced

Leligdowicz et al Critical Care (2016) 20217 Page 8 of 14

leading to fluid electrolyte and acid-base imbalancewith multisystem organ dysfunction there are no Ebola-specific therapies yet to be proven effective However in-tensive care medicine comprises experiential andevidence-based organ-supportive care which shouldguide the care of patients with EVDmdashattention to fluidelectrolyte and acid-base balance initiation of empiricand specific anti-infective therapy and support for renalinjury and respiratory failure as occurs for other poten-tially self-limited and survivable illnesses Among pa-tients with EVD treated in the USA and Europe 41 were deemed to have critical illness with 70 receivingsupplemental oxygen 22 with acute respiratory dis-tress syndrome 26 invasive mechanical ventilation30 intravenous vasoactive medications and 19 re-quiring dialysis [40]For the most severely ill patients clinical judgment is

always necessary to balance risks and benefits of certainresuscitation strategies including the initiation of car-diopulmonary resuscitation (CPR) [28 87] While thereis a lack of clinical experience with CPR in EVD pa-tients it may be a reasonable consideration while cor-recting reversible abnormalities (ie hypoxia severeelectrolyte disturbance arrhythmias) in settings wherethe option for advanced life-support exists The decisionto provide CPR should be guided by its medical indicationand utility in that context the ability to provide effectiveCPR and the safety of those providing care includingsafe donning and doffing of PPE in addition to patientpreferences [88 89]Fifth as with all critical illness medical technical care

is only one dimension of our support for patients andtheir families Patients with EVD and their families requiremechanisms to stay in audio and visual contact throughoutthe illnessmdashideally visual contact through transparent bar-riers or at safe distance or direct contact with superviseddonning and doffing of PPEmdashin addition to substantialpsychosocial support during and after EVD

Ebola-specific pharmacological prevention andtherapeuticsCurrent EVD treatment focuses on supportive care [70]as there are no specific treatment options yet to beproven effective [70 90 91] A number of Ebola-specifictreatment strategies have undergone preliminary clinicaltrial investigation including convalescent plasma Favi-piravir Brincidofovir and TMK-130803 [92ndash97] Trans-fusion of convalescent whole blood or plasma donatedby EVD survivors has been used in this and prior EVDoutbreaks [98] in an uncontrolled or compassionate-usebasis [25 79 81 99] and in animal models [100 101]One of three clinical trials of convalescent plasma ther-apy [94] has been completed and reported [102] In thisnonrandomized comparison to historical controls

transfusion of up to 500 ml convalescent plasma withunknown levels of neutralizing antibodies in 84 patientswith confirmed EVD was not associated with a signifi-cant improvement in survival While there were no ser-ious adverse reactions in this trial transfusion-relatedacute lung injury was described during convalescentplasma therapy in Spain [25] Favipiravir (ToyamaJapan) [103] a pre-existing influenza virus inhibitor hasbeen administered for compassionate use outside WestAfrica [37 38 42] In a multicenter nonrandomizedclinical trial in Guinea [104] 111 patients receiving Favi-piravir had similar survival to that based upon historicalcontrol patients The trial authors suggested that Favipir-avir should be further studied in patients with mediumto high viremia but not in those with very high viremia[105] Brincidofovir (Chimerix USA) a nucleotide ana-log that inhibits RNA-polymerase with in vitro activityagainst Ebola [106] was administered to a small numberof EVD patients for uncontrolled compassionate use[42 79 81 99] and was tested in a phase 2 clinical trialin Liberia [95] that was stopped after the manufacturerwithdrew study support [107] TKM-130803 is a formula-tion of lipid-nanoparticle-encapsulated small interferingribonucleic acids (siRNA) targeting two proteins involvedin Ebola virus transcription and replication (TekmiraUSA Canada) It was used in nonhuman primate Ebolavirus infection as a postexposure treatment strategy[108] and in patients medically evacuated from WestAfrica in uncontrolled compassionate use [79 81]However a phase 2 clinical trial (RAPIDE-TKM) inSierra Leone [96] was halted according to pre-establishedstopping rules [109]ZMapp a monoclonal antibody cocktail (Leafbio

USA) [110] has been used under the emergency investi-gational new drug approvals from the Food and DrugAdministration in patients treated in the USA WestAfrica and Western Europe [40 76 111] ZMapp treat-ment of rhesus macaques resulted in 100 survival evenwhen started 5 days after lethal EBOV infection [110] Inthe only randomized controlled trial of an investigationaltherapeutic for EVD ZMapp plus standard of care wascompared to standard of care alone for EVD patients infour countries including the three most impacted WestAfrican countries Due to the decline in EVD cases thisunblinded ZMapp randomized controlled trial onlyenrolled 72 of the prespecified target goal of 200 EVD pa-tients data were analyzed for 71 EVD patients and mor-tality in the ZMapp treatment group was 22 versus37 in the untreated group but this difference was notstatistically significant [112 113]The open-label uncontrolled and selected administra-

tion of other agents such as amiodarone [114] HMG-CoA reductase inhibitors and angiotensin II receptorantagonists [115] and therapies to counteract vascular

Leligdowicz et al Critical Care (2016) 20217 Page 9 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

leading to fluid electrolyte and acid-base imbalancewith multisystem organ dysfunction there are no Ebola-specific therapies yet to be proven effective However in-tensive care medicine comprises experiential andevidence-based organ-supportive care which shouldguide the care of patients with EVDmdashattention to fluidelectrolyte and acid-base balance initiation of empiricand specific anti-infective therapy and support for renalinjury and respiratory failure as occurs for other poten-tially self-limited and survivable illnesses Among pa-tients with EVD treated in the USA and Europe 41 were deemed to have critical illness with 70 receivingsupplemental oxygen 22 with acute respiratory dis-tress syndrome 26 invasive mechanical ventilation30 intravenous vasoactive medications and 19 re-quiring dialysis [40]For the most severely ill patients clinical judgment is

always necessary to balance risks and benefits of certainresuscitation strategies including the initiation of car-diopulmonary resuscitation (CPR) [28 87] While thereis a lack of clinical experience with CPR in EVD pa-tients it may be a reasonable consideration while cor-recting reversible abnormalities (ie hypoxia severeelectrolyte disturbance arrhythmias) in settings wherethe option for advanced life-support exists The decisionto provide CPR should be guided by its medical indicationand utility in that context the ability to provide effectiveCPR and the safety of those providing care includingsafe donning and doffing of PPE in addition to patientpreferences [88 89]Fifth as with all critical illness medical technical care

is only one dimension of our support for patients andtheir families Patients with EVD and their families requiremechanisms to stay in audio and visual contact throughoutthe illnessmdashideally visual contact through transparent bar-riers or at safe distance or direct contact with superviseddonning and doffing of PPEmdashin addition to substantialpsychosocial support during and after EVD

Ebola-specific pharmacological prevention andtherapeuticsCurrent EVD treatment focuses on supportive care [70]as there are no specific treatment options yet to beproven effective [70 90 91] A number of Ebola-specifictreatment strategies have undergone preliminary clinicaltrial investigation including convalescent plasma Favi-piravir Brincidofovir and TMK-130803 [92ndash97] Trans-fusion of convalescent whole blood or plasma donatedby EVD survivors has been used in this and prior EVDoutbreaks [98] in an uncontrolled or compassionate-usebasis [25 79 81 99] and in animal models [100 101]One of three clinical trials of convalescent plasma ther-apy [94] has been completed and reported [102] In thisnonrandomized comparison to historical controls

transfusion of up to 500 ml convalescent plasma withunknown levels of neutralizing antibodies in 84 patientswith confirmed EVD was not associated with a signifi-cant improvement in survival While there were no ser-ious adverse reactions in this trial transfusion-relatedacute lung injury was described during convalescentplasma therapy in Spain [25] Favipiravir (ToyamaJapan) [103] a pre-existing influenza virus inhibitor hasbeen administered for compassionate use outside WestAfrica [37 38 42] In a multicenter nonrandomizedclinical trial in Guinea [104] 111 patients receiving Favi-piravir had similar survival to that based upon historicalcontrol patients The trial authors suggested that Favipir-avir should be further studied in patients with mediumto high viremia but not in those with very high viremia[105] Brincidofovir (Chimerix USA) a nucleotide ana-log that inhibits RNA-polymerase with in vitro activityagainst Ebola [106] was administered to a small numberof EVD patients for uncontrolled compassionate use[42 79 81 99] and was tested in a phase 2 clinical trialin Liberia [95] that was stopped after the manufacturerwithdrew study support [107] TKM-130803 is a formula-tion of lipid-nanoparticle-encapsulated small interferingribonucleic acids (siRNA) targeting two proteins involvedin Ebola virus transcription and replication (TekmiraUSA Canada) It was used in nonhuman primate Ebolavirus infection as a postexposure treatment strategy[108] and in patients medically evacuated from WestAfrica in uncontrolled compassionate use [79 81]However a phase 2 clinical trial (RAPIDE-TKM) inSierra Leone [96] was halted according to pre-establishedstopping rules [109]ZMapp a monoclonal antibody cocktail (Leafbio

USA) [110] has been used under the emergency investi-gational new drug approvals from the Food and DrugAdministration in patients treated in the USA WestAfrica and Western Europe [40 76 111] ZMapp treat-ment of rhesus macaques resulted in 100 survival evenwhen started 5 days after lethal EBOV infection [110] Inthe only randomized controlled trial of an investigationaltherapeutic for EVD ZMapp plus standard of care wascompared to standard of care alone for EVD patients infour countries including the three most impacted WestAfrican countries Due to the decline in EVD cases thisunblinded ZMapp randomized controlled trial onlyenrolled 72 of the prespecified target goal of 200 EVD pa-tients data were analyzed for 71 EVD patients and mor-tality in the ZMapp treatment group was 22 versus37 in the untreated group but this difference was notstatistically significant [112 113]The open-label uncontrolled and selected administra-

tion of other agents such as amiodarone [114] HMG-CoA reductase inhibitors and angiotensin II receptorantagonists [115] and therapies to counteract vascular

Leligdowicz et al Critical Care (2016) 20217 Page 9 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

leak (FX06) [38] preclude any conclusions In an obser-vational study examining temporal trends in mortalityamong patients with EVD in one ETU in Guinea 125 of194 (644 ) patients receiving artemetherndashlumefantrinefor malaria prophylaxis died as compared with 36 of 71patients receiving artesunatendashamodiaquine (507 )In adjusted analyses the risk ratio was 069 (95 confidence interval 054 to 089) with a stronger effectobserved among patients without malaria [116] Thesefindings have not been confirmed in a randomizedclinical trialTwo vaccine candidates demonstrated efficacy in

nonhuman primates [92 117 118] A recombinantreplication-competent vesicular stomatitis virus-basedvaccine expressing a surface glycoprotein of Zaire ebola-virus rVSVΔG-EBOV-GP (rVSV) [118 119] was evaluatedin an open-label ring vaccination trial involving 7651people in 90 clusters randomized to immediate or delayed(21 days) administration The vaccine was well toleratedand in the immediate vaccination group there wereno new EVD cases while in the delayed vaccinationgroup there were 16 EVD cases [120] Another candidatevaccine cAd3-EBOV (cAd3) [117] remains under investi-gation [92 121] Other vaccine candidates are also underdevelopment and evaluation [122 123]

Post-exposure ProphylaxisSeveral healthcare personnel received post-exposureprophylaxis with different interventions including acandidate Ebola vaccine following potential high-riskexposures to Ebola virus although Ebola virus diseasedid not occur in these individuals no conclusions can bemade about the effectiveness of these uncontrolled inter-ventions [124ndash126]

Ethical challenges in caring for patients withEbola virus diseaseEach of the commonly applied four principles of medicalbioethics faces numerous threats in treating patientswith EVD [87] A symptomatic patientrsquos autonomy tonot seek treatment (and not be isolated) is weighedagainst the threat of disease transmission by staying inthe community The injustice of treatment variabilityacross regions and over time places patients at differen-tial risk of death In acting beneficently healthcareworkers inherently place themselves at some risk A nat-ural response is to balance that risk with the duty tohelp This frequently conspires against greater numbersof health workers responding to an Ebola outbreak Theduty to nonmaleficence doing no harm is a daily con-undrum through potential delays in routine diagnosticwork-up for common illnesses because of a lack of diag-nostic testing or in resource-constrained environments

inadequate space to separate potentially infectious suspectpatients along a gradient of risk

Post-Ebola syndromeWith over 11000 EVD survivors there is increased recog-nition of a post-Ebola syndrome in the convalescentperiod characterized by mental health and cognitivesequelae chronic headaches insomnia arthralgias audi-tory disturbances and ocular effects including sight-threatening uveitis [127ndash132] It is uncertain whetherthese manifestations are due to direct viral cytopathiceffect in immune-privileged compartments or postin-fectious immune-mediated inflammation [133ndash135]

Research directionsAlthough this EVD outbreak narrowed some knowledgegaps pathophysiology and the immunological response toacute infection and convalescence is still minimally char-acterized Access to rapid point-of-care EVD diagnosticcapacity to differentiate between other common febrileillnesses [136] is critical because the early presentation ofEVD has a broad differential diagnosis [5 7 34] Labora-tory testing to identify prognostic indicators could helpguide clinical care Evaluation of specific antiviral therap-ies is critical as is evaluation of commonly used treatmentsfor which there is still very limited evidence (eg empiricantibiotics anti-diarrheal agents and fluid replacementcomposition and volume) The safety and functionality ofPPE must be improved Standardized easy-to-use clinicalcharting and human resources for data entry should bemade available to support cohort studies and clinical trialsWhile it seems intuitive that provision of advancedsupportive and critical care improves patient outcomesoperationalizing and evaluating increased levels of care toresource-challenged environments is needed Preparedresearch protocols that can be rapidly adapted to country-specific settings and quickly implemented could reduceresearch delays in future outbreaks Following patientswho survive EVD is important to better characterizeimmune correlates of virus clearance and host geneticfactors that contribute to survival and to better addressmorbidity of the post-Ebola syndrome

ConclusionsThe provision of advanced supportive and critical carefor EVD patients while challenging is possible in bothWest African and more developed healthcare settingsCreating and evaluating context-appropriate intensivecare capacity is a knowledge translation priority Theexperience of this outbreak emphasizes that in additionto evaluating specific medical treatments improving theglobal capacity to provide supportive critical care topatients with severe illness may be associated with thegreatest opportunity to improve patient outcomes

Leligdowicz et al Critical Care (2016) 20217 Page 10 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

Additional file

Additional file 1 Weblink references for Tables 1ndash3 (DOCX 124 kb)

AbbreviationsCPR cardiopulmonary resuscitation EBOV Ebola virus ETU Ebola TreatmentUnit EVD Ebola virus disease ICU intensive care unit IL interleukinIPC infection prevention and control PPE personal protective equipmentRT-PCR real-time reverse transcription polymerase chain reaction

Authorsrsquo contributionsRAF AL WAFII TEF and TMU conceived of the study participated in itsdesign and coordination collected data performed the statistical analysisand drafted the manuscript NKJA GP FL TMU CC STJ LR AV JH SM MFIC EIB MCL JSS DBM DGB NS AC TOD SM MJ SD and GMLIII participatedin the design of the study helped in data collection and helped to revisethe manuscript All authors read and approved the final manuscript

Competing interestsThe authors declare that they have no competing interests

DisclaimerThe findings and conclusions in this report are those of the authors and donot necessarily represent the official position of the Centers for DiseaseControl and Prevention

Author details1Interdepartmental Division of Critical Care University of Toronto TorontoON Canada 2Department of Medicine University of North Carolina ChapelHill NC USA 3Centers for Disease Control and Prevention Atlanta GeorgiaUSA 4Defence Medical Services Whittington Barracks Lichfield UK5Liverpool School of Tropical Medicine Liverpool Merseyside UK6Department of Critical Care Medicine Sunnybrook Health Sciences CentreToronto ON Canada 7Emergency NGO Milan Italy 8Department ofMedicine Universiteacute de Sherbrooke Sherbrooke Quebec Canada9Polyclinique Bordeaux Nord Aquitaine Bordeaux France 10Department ofMedicine University of Washington Seattle Washington USA 11Departmentof Medicine University of Maryland Baltimore MD USA 12Centre derecherche de lrsquoinstitut Universitaire de Cardiologie et de Pneumologie deQueacutebec Quebec City Quebec Canada 13Division of Infectious DiseasesUniversity of British Columbia Vancouver BC Canada 14Department ofPaediatrics University of British Columbia Vancouver BC Canada15Infectious Diseases Institute College of Health Sciences MakerereUniversity Kampala Uganda 16Department of Infectious and ParasiticDiseases Donka Hospital Conakry Guinea 17Department of PediatricsSchool of Medicine and School of Public Health and Tropical MedicineTulane University New Orleans LA USA 18Department of PreventiveMedicine and Biometrics Uniformed Services University Bethesda MD USA19Department of Pandemic and Epidemic Diseases World HealthOrganization Geneva Switzerland 20Division of Infectious DiseasesSunnybrook Health Sciences Centre Toronto ON Canada 21Department ofClinical Sciences Liverpool School of Tropical Medicine Liverpool UK22Department of Medicine University of Toronto Toronto ON Canada23Department of Infection Royal Free London NHS Foundation TrustLondon UK 24Acute Medicine and Intensive Care Derriford HospitalPlymouth UK 25Department of Infectious Diseases Emory UniversityHospital Atlanta Georgia USA

Received 3 March 2016 Accepted 26 April 2016

References1 Baize S Pannetier D Oestereich L et al Emergence of Zaire Ebola virus

disease in Guinea N Engl J Med 2014371(15)1418ndash252 Bres P The epidemic of Ebola haemorrhagic fever in Sudan and Zaire 1976

introductory note Bull World Health Organ 197856(2)2453 CDC Outbreaks Chronology Ebola Virus Disease httpwwwcdcgovvhf

ebolaoutbreakshistorychronologyhtml Accessed 7 Sep 20154 Feldmann H Geisbert TW Ebola haemorrhagic fever Lancet 2011377(9768)

849ndash62

5 Bah EI Lamah MC Fletcher T et al Clinical presentation of patients withEbola virus disease in Conakry Guinea N Engl J Med 2015372(1)40ndash7

6 Schieffelin JS Shaffer JG Goba A et al Clinical illness and outcomes inpatients with Ebola in Sierra Leone N Engl J Med 2014371(22)2092ndash100

7 Fauci AS Ebolamdashunderscoring the global disparities in health careresources N Engl J Med 2014371(12)1084ndash6

8 Kortepeter MG Bausch DG Bray M Basic clinical and laboratory features offiloviral hemorrhagic fever J Infect Dis 2011204 Suppl 3S810ndash6

9 Bwaka MA Bonnet MJ Calain P et al Ebola hemorrhagic fever in KikwitDemocratic Republic of the Congo clinical observations in 103 patientsJ Infect Dis 1999179 Suppl 1S1ndash7

10 Peters CJ LeDuc JW An introduction to Ebola the virus and the diseaseJ Infect Dis 1999179 Suppl 1ixndashxvi

11 WHO Ebola haemorrhagic fever in Zaire 1976 Bull World Health Organ197856(2)271ndash93

12 WHO Ebola haemorrhagic fever in Sudan 1976 Report of a WHOInternational Study Team Bull World Health Organ 197856(2)247ndash70

13 Gire SK Goba A Andersen KG et al Genomic surveillance elucidates Ebola virusorigin and transmission during the 2014 outbreak Science 2014345(6202)1369ndash72

14 CDC 2014 Ebola Outbreak in West Africa - Reported Cases Graphshttpwwwcdcgovvhfebolaoutbreaks2014-west-africacumulative-cases-graphshtml Accessed 7 Sep 2015

15 WHO Ebola Situation Reports httpappswhointebolaebola-situation-reports Accessed 20 May 2016

16 Team WHOER Ebola virus disease in West Africamdashthe first 9 months of theepidemic and forward projections N Engl J Med 2014371(16)1481ndash95

17 Victory KR Coronado F Ifono SO et al Ebola transmission linked to a singletraditional funeral ceremonymdashKissidougou Guinea December 2014-January 2015 MMWR Morb Mortal Wkly Rep 201564(14)386ndash8

18 WHO Interim infection prevention and control guidance for care of patientswith suspected or confirmed filovirus haemorrhagic fever in health-caresettings with focus on Ebola Geneva Switzerland WHO 2014

19 Johnson E Jaax N White J et al Lethal experimental infections of rhesusmonkeys by aerosolized Ebola virus Int J Exp Pathol 199576(4)227ndash36

20 Jaax N Jahrling P Geisbert T et al Transmission of Ebola virus (Zaire strain)to uninfected control monkeys in a biocontainment laboratory Lancet1995346(8991-8992)1669ndash71

21 Brearley MB Heaney MF Norton IN Physiological responses of medicalteam members to a simulated emergency in tropical field conditionsPrehosp Disaster Med 201328(2)139ndash44

22 WHO Health worker Ebola infections in Guinea Liberia and Sierra LeoneGeneva Switzerland WHO 2015

23 Suwantarat N Apisarnthanarak A Risks to healthcare workers with emergingdiseases lessons from MERS-CoV Ebola SARS and avian flu Curr OpinInfect Dis 201528(4)349ndash61

24 Lopaz MA Amela C Ordobas M et al First secondary case of Ebola outsideAfrica epidemiological characteristics and contact monitoring SpainSeptember to November 2014 Euro Surveill 201520(1)

25 Mora-Rillo M Arsuaga M Ramirez-Olivencia G et al Acute respiratory distresssyndrome after convalescent plasma use treatment of a patient with Ebolavirus disease contracted in Madrid Spain Lancet Respir Med 20153(7)554ndash62

26 Chevalier MS Chung W Smith J et al Ebola virus disease cluster in theUnited StatesmdashDallas County Texas 2014 MMWR Morb Mortal Wkly Rep201463(46)1087ndash8

27 Tartari E Allegranzi B Ang B et al Preparedness of institutions around theworld for managing patients with Ebola virus disease an infection controlreadiness checklist Antimicrob Resist Infect Control 2015422

28 Johnson DW Sullivan JN Piquette CA et al Lessons learned critical caremanagement of patients with Ebola in the United States Crit Care Med201543(6)1157ndash64

29 McElroy AK Erickson BR Flietstra TD et al Ebola hemorrhagic fever novelbiomarker correlates of clinical outcome J Infect Dis 2014210(4)558ndash66

30 Fletcher TE Fowler RA Beeching NJ Understanding organ dysfunction inEbola virus disease Intensive Care Med 201440(12)1936ndash9

31 WHO Case definition recommendations for Ebola or Marburg VirusDiseases 2014 httpwwwwhointcsrresourcespublicationsebolaebola-case-definition-contact-enpdf Accessed 7 Sep 2015

32 Martin P Laupland KB Frost EH et al Laboratory diagnosis of Ebola virusdisease Intensive Care Med 201541(5)895ndash8

33 WHO Clinical management of patients with viral haemorrhagic fevera pocket guide for the front-line health worker Geneva Switzerland WHO 2014

Leligdowicz et al Critical Care (2016) 20217 Page 11 of 14

34 Broadhurst MJ Kelly JD Miller A et al ReEBOV Antigen Rapid Test kit forpoint-of-care and laboratory-based testing for Ebola virus disease a fieldvalidation study Lancet 2015386(9996)867ndash74

35 Emond RT Evans B Bowen ET et al A case of Ebola virus infection Br MedJ 19772(6086)541ndash4

36 Nkoghe D Leroy EM Toung-Mve M et al Cutaneous manifestations offilovirus infections Int J Dermatol 201251(9)1037ndash43

37 Schibler M Vetter P Cherpillod P et al Clinical features and viral kinetics ina rapidly cured patient with Ebola virus disease a case report Lancet InfectDis 201515(9)1034ndash40

38 Wolf T Kann G Becker S et al Severe Ebola virus disease with vascularleakage and multiorgan failure treatment of a patient in intensive careLancet 2015385(9976)1428ndash35

39 Khan AS Tshioko FK Heymann DL et al The reemergence of Ebolahemorrhagic fever Democratic Republic of the Congo 1995Commission de Lutte contre les Epidemies a Kikwit J Infect Dis1999179 Suppl 1S76ndash86

40 Uyeki TM Mehta AK Davey RT Jr Liddell AM Wolf T Vetter P Schmiedel SGruumlnewald T Jacobs M Arribas JR Evans L Hewlett AL Brantsaeter ABIppolito G Rapp C Hoepelman AI Gutman J Working Group of the USndashEuropean Clinical Network on Clinical Management of Ebola Virus DiseasePatients in the US and Europe Clinical Management of Ebola Virus Diseasein the United States and Europe N Engl J Med 201618374(7)636ndash46

41 Chertow DS Kleine C Edwards JK et al Ebola virus disease in WestAfricamdashclinical manifestations and management N Engl J Med 2014371(22)2054ndash7

42 Kreuels B Wichmann D Emmerich P et al A case of severe Ebola virusinfection complicated by gram-negative septicemia N Engl J Med 2014371(25)2394ndash401

43 Fitzpatrick G Vogt F Moi Gbabai OB et al The contribution of Ebola viralload at admission and other patient characteristics to mortality in aMedecins Sans Frontieres Ebola Case Management Centre Kailahun SierraLeone JunendashOctober 2014 J Infect Dis 2015212(11)1752ndash8

44 Mupapa K Mukundu W Bwaka MA et al Ebola hemorrhagic fever andpregnancy J Infect Dis 1999179 Suppl 1S11ndash12

45 Towner JS Rollin PE Bausch DG et al Rapid diagnosis of Ebola hemorrhagicfever by reverse transcription-PCR in an outbreak setting and assessment ofpatient viral load as a predictor of outcome J Virol 200478(8)4330ndash41

46 Faye O Andronico A Faye O et al Use of viremia to evaluate the baselinecase fatality ratio of Ebola virus disease and inform treatment studies aretrospective cohort study PLoS Med 201512(12)e1001908

47 Lanini S Portella G Vairo F et al Blood kinetics of Ebola virus in survivorsand nonsurvivors J Clin Invest 2015125(12)4692ndash8

48 Rollin PE Bausch DG Sanchez A Blood chemistry measurements and D-dimer levels associated with fatal and nonfatal outcomes in humansinfected with Sudan Ebola virus J Infect Dis 2007196 Suppl 2S364ndash371

49 Fowler RA Fletcher T Fischer 2nd WA et al Caring for critically ill patientswith Ebola virus disease Perspectives from West Africa Am J Respir CritCare Med 2014190(7)733ndash7

50 West TE von Saint Andre-von Arnim A Clinical presentation and managementof severe Ebola virus disease Ann Am Thorac Soc 201411(9)1341ndash50

51 Cellarier GR Bordes J Karkowski L et al Safety feasibility and interest oftransthoracic echocardiography in a deployed French military Ebola virusdisease treatment center in Guinea Intensive Care Med 201541(8)1491ndash2

52 Auffermann WF Kraft CS Vanairsdale S et al Radiographic imaging for patientswith contagious infectious diseases how to acquire chest radiographs ofpatients infected with the Ebola virus AJR Am J Roentgenol 2015204(1)44ndash8

53 Bausch DG Towner JS Dowell SF et al Assessment of the risk of Ebolavirus transmission from bodily fluids and fomites J Infect Dis 2007196Suppl 2S142ndash7

54 Formenty P Leroy EM Epelboin A et al Detection of Ebola virus in oralfluid specimens during outbreaks of Ebola virus hemorrhagic fever in theRepublic of Congo Clin Infect Dis 200642(11)1521ndash6

55 Zaki SR Shieh WJ Greer PW et al A novel immunohistochemical assay forthe detection of Ebola virus in skin implications for diagnosis spread andsurveillance of Ebola hemorrhagic fever Commission de Lutte contre lesEpidemies a Kikwit J Infect Dis 1999179 Suppl 1S36ndash47

56 Rowe AK Bertolli J Khan AS et al Clinical virologic and immunologic follow-up of convalescent Ebola hemorrhagic fever patients and their householdcontacts Kikwit Democratic Republic of the Congo Commission de Luttecontre les Epidemies a Kikwit J Infect Dis 1999179 Suppl 1S28ndash35

57 Rodriguez LL De Roo A Guimard Y et al Persistence and genetic stabilityof Ebola virus during the outbreak in Kikwit Democratic Republic of theCongo 1995 J Infect Dis 1999179 Suppl 1S170ndash6

58 Varkey JB Shantha JG Crozier I et al Persistence of Ebola virus in ocularfluid during convalescence N Engl J Med 2015372(25)2423ndash7

59 Deen GF Knust B Broutet N et al Ebola RNA persistence in semen of Ebolavirus disease survivorsmdashpreliminary report N Engl J Med 2015 doi101056NEJMoa1511410 httpwwwnejmorgdoipdf101056NEJMoa1511410

60 Mate SE Kugelman JR Nyenswah TG et al Molecular evidence of sexualtransmission of Ebola virus N Engl J Med 2015373(25)2448ndash54

61 Jacobs M Rodger A Bell DJ Bhagani S Cropley I Filipe A Gifford RJ Hopkins SHughes J Jabeen F Johannessen I Karageorgopoulos D Lackenby A Lester RLiu RS MacConnachie A Mahungu T Martin D Marshall N Mepham S OrtonR Palmarini M Patel M Perry C Peters SE Porter D Ritchie D Ritchie NDSeaton RA Sreenu VB Templeton K Warren S Wilkie GS Zambon M Gopal RThomson EC Late Ebola virus relapse causing meningoencephalitis a casereport Lancet 2016 May 18 pii S0140ndash6736(16)30386-5 doi101016S0140-6736(16)30386-5 [Epub ahead of print]

62 WHO Interim advice on the sexual transmission of the Ebola virus diseaseSexual and reproductive health httpwwwwhointreproductivehealthtopicsrtisebola-virus-semenen Accessed 22 Sep 2015

63 CDC Interim Guidance for Management of Survivors of Ebola Virus Disease in USHealthcare Settings 2016 httpwwwcdcgovvhfebolahealthcare-usevaluating-patientsguidance-for-management-of-survivors-ebolahtml Accessed 6 Apr 2016

64 Brett-Major DM Jacob ST Jacquerioz FA et al Being ready to treat Ebolavirus disease patients Am J Trop Med Hyg 201592(2)233ndash7

65 Dunser MW Festic E Dondorp A et al Recommendations for sepsismanagement in resource-limited settings Intensive Care Med 201238(4)557ndash74

66 Maitland K Kiguli S Opoka RO et al Mortality after fluid bolus in Africanchildren with severe infection N Engl J Med 2011364(26)2483ndash95

67 Andrews B Muchemwa L Kelly P et al Simplified severe sepsis protocola randomized controlled trial of modified early goal-directed therapy inZambia Crit Care Med 201442(11)2315ndash24

68 Kortepeter MG Lawler JV Honko A et al Real-time monitoring ofcardiovascular function in rhesus macaques infected with Zaire ebolavirusJ Infect Dis 2011204 Suppl 3S1000ndash10

69 Roberts I Perner A Ebola virus disease clinical care and patient-centredresearch Lancet 2014384(9959)2001ndash2

70 Perner A Fowler RA Bellomo R et al Ebola care and research protocolsIntensive Care Med 201541(1)111ndash4

71 Chertow DS Uyeki TM DuPont HL Loperamide therapy for voluminousdiarrhea in Ebola virus disease J Infect Dis 2015211(7)1036ndash7

72 Rees PS Lamb LE Nicholson-Roberts TC et al Safety and feasibility of astrategy of early central venous catheter insertion in a deployed UK militaryEbola virus disease treatment unit Intensive Care Med 201541(5)735ndash43

73 Paterson ML Callahan CW The use of intraosseous fluid resuscitation in apediatric patient with Ebola virus disease J Emerg Med 201549(6)962ndash4

74 Lamontagne F Clement C Fletcher T et al Doing todayrsquos work superblywellmdashtreating Ebola with current tools N Engl J Med 2014371(17)1565ndash6

75 Murthy S Ebola Clinical Care authors group Ebola and provision of criticalcare Lancet 2015385(9976)1392ndash3

76 Lyon GM Mehta AK Varkey JB et al Clinical care of two patients with Ebolavirus disease in the United States N Engl J Med 2014371(25)2402ndash9

77 Parra JM Salmeron OJ Velasco M The first case of Ebola virus diseaseacquired outside Africa N Engl J Med 2014371(25)2439ndash40

78 Connor Jr MJ Kraft C Mehta AK et al Successful delivery of RRT in Ebolavirus disease J Am Soc Nephrol 201526(1)31ndash7

79 Kraft CS Hewlett AL Koepsell S et al The use of TKM-100802 and convalescentplasma in 2 patients with Ebola virus disease in the United States Clin Infect Dis201561(4)496ndash502

80 Rubin EJ Baden LR Out of Africamdashcaring for patients with Ebola N Engl JMed 2014371(25)2430ndash2

81 Liddell AM Davey Jr RT Mehta AK et al Characteristics and clinical managementof a cluster of 3 patients with Ebola virus disease including the first domesticallyacquired cases in the United States Ann Intern Med 2015163(2)81ndash90

82 Sueblinvong V Johnson DW Weinstein GL et al Critical care for multipleorgan failure secondary to Ebola virus disease in the United States Crit CareMed 201543(10)2066ndash75

83 Stephens DS Ribner BS Gartland BD et al Ebola virus disease experienceand decision making for the first patients outside of Africa PLoS Med 201512(7)e1001857

Leligdowicz et al Critical Care (2016) 20217 Page 12 of 14

84 Boggild AK Esposito DH Kozarsky PE et al Differential diagnosis of illness intravelers arriving from Sierra Leone Liberia or Guinea a cross-sectional study fromthe GeoSentinel Surveillance Network Ann Intern Med 2015162(11)757ndash64

85 Tan KR Cullen KA Koumans EH et al Inadequate diagnosis andtreatment of malaria among travelers returning from Africa during theEbola epidemicmdashUnited States 2014ndash2015 MMWR Morb Mortal WklyRep 201665(2)27ndash9

86 Decker BK Sevransky JE Barrett K et al Preparing for critical care services topatients with Ebola Ann Intern Med 2014161(11)831ndash2

87 Halpern SD Emanuel EJ Ethical guidance on the use of life-sustainingtherapies for patients with Ebola in developed countries Ann Intern Med2015162(4)304ndash5

88 Torabi-Parizi P Davey Jr RT Suffredini AF et al Ethical and practicalconsiderations in providing critical care to patients with Ebola virus diseaseChest 2015147(6)1460ndash6

89 Canadian Critical Care Society Canadian Association of EmergencyPhysicians Association of Medical Microbiology amp Infectious DiseasesCanada Ebola Clinical Care Guidelines A guide for clinicians in CanadaReport 2 2014 Organized by the Public Health Agency of Canadahttpwwwcanadiancriticalcareorg_assetsEbola20Clinical20Care20Guidelines_ENGpdf Accessed 7 Sept 2015

90 Friedrich BM Trefry JC Biggins JE et al Potential vaccines and post-exposure treatments for filovirus infections Viruses 20124(9)1619ndash50

91 Bishop BM Potential and emerging treatment options for Ebola virusdisease Ann Pharmacother 201549(2)196ndash206

92 WHO WHO Ebola RampD Effortmdashvaccines therapies diagnostics httpwwwwhointmedicinesebola-treatmentebola_r_d_efforten Accessed 27 Sep 2015

93 WHO Potential new Ebola therapies and vaccines Geneva Switzerland WHO 201494 ClincalTrialsgov Studies of convalescent plasma use in Ebola Virus Disease

httpsclinicaltrialsgovct2resultsterm=convalescent+plasma+ebolaampSearch=Search Accessed 7 Sep 2015

95 ClincalTrialsgov An open-label multicenter study of the safety and anti viralactivity of brincidofovir (BCV CMX001) for Ebola Virus Disease NCT02271347httpswwwclinicaltrialsgovct2showNCT0227-1347 Accessed 27 Dec 2014

96 PanAfricanClinicalTrialsRegistry Rapid assessment of potential interventionsamp drugs for Ebola (RAPIDE) -TKM httpwwwpactrorgATMWebappmanageratmatmregistry_nfpb=trueamp_windowLabel=BasicSearchUpdateController_1ampBasicSearchUpdateController_1_actionOverride=2Fpageflows2Ftrial2FbasicSearchUpdate2FviewTrailampBasicSearchUpdateController_ Accessed 23 Sep 2015

97 Sissoko D Laouenan C Folkesson E et al Experimental treatment withfavipiravir for Ebola virus disease (the JIKI trial) a historically controlledsingle-arm proof-of-concept trial in Guinea PLoS Med 201613(3)e1001967

98 Mupapa K Massamba M Kibadi K et al Treatment of Ebola hemorrhagicfever with blood transfusions from convalescent patients InternationalScientific and Technical Committee J Infect Dis 1999179 Suppl 1S18ndash23

99 Florescu DF Kalil AC Hewlett AL et al Administration of brincidofovir andconvalescent plasma in a patient with Ebola virus disease Clin Infect Dis201561(6)969ndash73

100 Takada A Ebihara H Jones S et al Protective efficacy of neutralizingantibodies against Ebola virus infection Vaccine 200725(6)993ndash9

101 Marzi A Yoshida R Miyamoto H et al Protective efficacy of neutralizingmonoclonal antibodies in a nonhuman primate model of Ebolahemorrhagic fever PLoS One 20127(4)e36192

102 van Griensven J Edwards T de Lamballerie X et al Evaluation of convalescentplasma for Ebola virus disease in Guinea N Engl J Med 2016374(1)33ndash42

103 Oestereich L Ludtke A Wurr S et al Successful treatment of advancedEbola virus infection with T-705 (favipiravir) in a small animal modelAntiviral Res 201410517ndash21

104 ClincalTrialsgov Efficacy of favipiravir against Ebola (JIKI) NCT02329054 Availablefrom httpsclinicaltrialsgovct2showNCT02329054 Accessed 7 Sep 2015

105 Sissoko D Folkesson E Abdoul M et al Favipiravir in patients with Ebola virusdisease early results of the JIKI trial in Guinea In Conference on Retrovirusesand Opportunistic Infections Seattle USA IASndashUSACROI Foundation2015 httpwwwcroiconferenceorgsessionsfavipiravir-patients-ebola-virus-disease-early-results-jiki-trial-guinea Accessed 7 Sept 2015

106 Chimerix Inc Brincidofovir httpwwwchimerixcomdiscovery-clinical-trialsbrincidofovirbrincidofovir-for-ebola Accessed 27 Dec 2014

107 Trust W Wellcome Trust-funded Ebola treatment trial stopped in LiberiahttpwwwwellcomeacukNewsMedia-officePress-releases2015WTP058609htm Accessed 7 Sep 2015

108 Geisbert TW Lee AC Robbins M et al Postexposure protection ofnon-human primates against a lethal Ebola virus challenge with RNAinterference a proof-of-concept study Lancet 2010375(9729)1896ndash905

109 Dunning J Sahr F Rojek A Gannon F Carson G Idriss B Massaquoi T GandiR Joseph S Osman HK Brooks TJ Simpson AJ Goodfellow I Thorne L AriasA Merson L Castle L Howell-Jones R Pardinaz-Solis R Hope-Gill B Ferri MGrove J Kowalski M Stepniewska K Lang T Whitehead J Olliaro P Samai MHorby PW RAPIDE-TKM trial team Experimental Treatment of Ebola VirusDisease with TKM-130803 A Single-Arm Phase 2 Clinical Trial PLoS Med2016 Apr 1913(4)e1001997 doi101371journalpmed1001997

110 Qiu X Wong G Audet J et al Reversion of advanced Ebola virus diseasein nonhuman primates with ZMapp Nature 2014514(7520)47ndash53

111 Goodman JL Studying ldquosecret serumsrdquomdashtoward safe effective Ebolatreatments N Engl J Med 2014371(12)1086ndash9

112 Davey RTftM-NPIST NIAID NIH Bethesda MD USA PREVAIL II arandomized controlled trial of ZMapptrade in acute Ebola virus infectionIn Conference on Retroviruses and Opportunistic Infections (CROI)Boston Massachusetts USA IASndashUSACROI Foundation 2016 httpwwwcroiconferenceorgsessionsprevail-ii-randomized-controlled-trial-zmapptrade-acute-ebola-virus-infection Accessed 23 Feb 2016

113 Dodd LE Proschan MA Neuhaus J Koopmeiners JS Neaton J Beigel JDBarrett K Lane HC Davey RT Jr Design of a Randomized Controlled Trial forEbola Virus Disease Medical Countermeasures PREVAIL II the Ebola MCMStudy J Infect Dis 2016 Jun 15213(12)1906ndash13

114 Gehring G Rohrmann K Atenchong N et al The clinically approveddrugs amiodarone dronedarone and verapamil inhibit filovirus cell entryJ Antimicrob Chemother 201469(8)2123ndash31

115 Fedson DS Jacobson JR Rordam OM et al Treating the host response toEbola virus disease with generic statins and angiotensin receptor blockersMBio 20156(3)e00716

116 Gignoux E Azman AS de Smet M et al Effect of artesunate-amodiaquineon mortality related to Ebola virus disease N Engl J Med 2016374(1)23ndash32

117 Stanley DA Honko AN Asiedu C et al Chimpanzee adenovirus vaccinegenerates acute and durable protective immunity against ebolaviruschallenge Nat Med 201420(10)1126ndash9

118 Geisbert TW Geisbert JB Leung A et al Single-injection vaccine protectsnonhuman primates against infection with marburg virus and three speciesof Ebola virus J Virol 200983(14)7296ndash304

119 Agnandji ST Huttner A Zinser ME et al Phase 1 trials of rVSV Ebola vaccine inAfrica and Europemdashpreliminary report N Engl J Med 2016374(17)1647ndash1660

120 Henao-Restrepo AM Longini IM Egger M et al Efficacy and effectivenessof an rVSV-vectored vaccine expressing Ebola surface glycoproteininterim results from the Guinea ring vaccination cluster-randomised trialLancet 2015386(9996)857ndash66

121 De Santis O Audran R Pothin E et al Safety and immunogenicity of achimpanzee adenovirus-vectored Ebola vaccine in healthy adults arandomised double-blind placebo-controlled dose-finding phase 12astudy Lancet Infect Dis 201616(3)311ndash320

122 Sarwar UN Costner P Enama ME Berkowitz N Hu Z Hendel CS Sitar SPlummer S Mulangu S Bailer RT Koup RA Mascola JR Nabel GJ SullivanNJ Graham BS Ledgerwood JE VRC 206 Study Team Safety andimmunogenicity of DNA vaccines encoding Ebolavirus and Marburgviruswild-type glycoproteins in a phase I clinical trial J Infect Dis 2015211(4)549ndash57

123 Milligan ID Gibani MM Sewell R et al Safety and Immunogenicity ofNovel Adenovirus Type 26- and Modified Vaccinia Ankara-Vectored EbolaVaccines A Randomized Clinical Trial JAMA 2016315(15)1610ndash1623

124 Wong KK Davey RT Jr Hewlett AL Kraft CS Mehta AK Mulligan MJ Beck ADorman W Kratochvil CJ Lai L Palmore TN Rogers S Smith PW SuffrediniAF Wolcott M Stroumlher U Uyeki TM Use of Postexposure Prophylaxis AfterOccupational Exposure to Zaire ebolavirus Clin Infect Dis 2016 Apr 26 piiciw256 [Epub ahead of print]

125 Jacobs M Aarons E Bhagani S Buchanan R Cropley I Hopkins S Lester RMartin D Marshall N Mepham S Warren S Rodger A Post-exposureprophylaxis against Ebola virus disease with experimental antiviral agentsa case-series of health-care workers Lancet Infect Dis 201515(11)1300ndash4

126 Lai L Davey R Beck A Xu Y Suffredini AF Palmore T Kabbani S Rogers SKobinger G Alimonti J Link CJ Jr Rubinson L Stroumlher U Wolcott MDorman W Uyeki TM Feldmann H Lane HC Mulligan MJ Emergencypostexposure vaccination with vesicular stomatitis virus-vectored Ebolavaccine after needlestick JAMA 2015313(12)1249ndash55

Leligdowicz et al Critical Care (2016) 20217 Page 13 of 14

127 Nanyonga M Saidu J Ramsay A et al Sequelae of Ebola virus diseaseKenema District Sierra Leone Clin Infect Dis 201662(1)125ndash6

128 Epstein L Wong KK Kallen AJ et al Post-Ebola signs and symptoms inUS survivors N Engl J Med 2015373(25)2484ndash6

129 Qureshi AI Chughtai M Loua TO et al Study of Ebola virus diseasesurvivors in Guinea Clin Infect Dis 201561(7)1035ndash42

130 Clark DV Kibuuka H Millard M et al Long-term sequelae after Ebola virusdisease in Bundibugyo Uganda a retrospective cohort study Lancet InfectDis 201515(8)905ndash12

131 Mattia JG Vandy MJ Chang JC et al Early clinical sequelae of Ebolavirus disease in Sierra Leone a cross-sectional study Lancet Infect Dis201616(3)331ndash338

132 Vetter P Kaiser L Schibler M et al Sequelae of Ebola virus disease theemergency within the emergency Lancet Infect Dis 2016 doi101016S1473-3099(16)00077-3 httpwwwsciencedirectcomsciencearticlepiiS1473309916000773

133 Lee-Kwan SH DeLuca N Adams M et al Support services for survivors ofebola virus diseasemdashSierra Leone 2014 MMWR Morb Mortal Wkly Rep201463(50)1205ndash6

134 WHO Sierra Leone Helping the Ebola survivors turn the page httpwwwwhointfeatures2014post-ebola-syndromeen Accessed 7 Jul 2015

135 WHO A story of Ebola survival and return httpwwwwhointtdrnews2014ebola-survival-returnen Accessed 5 Sept 2015

136 Schoepp RJ Rossi CA Khan SH et al Undiagnosed acute viral febrileillnesses Sierra Leone Emerg Infect Dis 201420(7)1176ndash82

137 CNN American Ebola patient released from Nebraska hospital httpwwwcnncom20140925healthebola-american-patient Accessed 27 Sep 2015

Leligdowicz et al Critical Care (2016) 20217 Page 14 of 14