Accidental Hypothermia
Cass DjurforsMay 8, 2003
Case
• Three avalanche workers caught in an avalanche
• One partially buried called on radio repeater immediately to mobilize rescue team and local paramedics by helicopter
• Plan to fly direct to local ED (Scene beyond range of STARS without refuel and nearby fuel cache buried in winter snow)
• Other two completely buried
Case
• Partially buried victim pulls shovel from rucksack on back and digs self out, performs transceiver search to locate first buried who comes up breathing
• Continues search and digs up second buried who is VSA and so begins CPR
• Burial time 40 minutes.
Case
• Paramedics land and apply monitor pads to show sinus bradycardia, confirm VSA, continue CPR
• Endotracheal intubation, bundle and fly to nearby regional ED
• Sinus bradycardia deteriorates en route to ventricular fibrillation
• Pilot does not allow defibrillation in flight
Case
• Local ED prepared with 2 EP’s, 1 anaesthetist, 1 GP surgeon, 7 nurses, various support personnel
• Patient arrives asystolic• Initial esophageal temp probe
27.5oC
Case• Management as follows:
– Confirm ETT placement– Humidified O2– 1L NS at 41C by Level One Infuser– Switch Level One Infuser to 3l NS irrigation bags for
pleural lavage via 36F tube left 2nd intercostal space and second tube 5th intercostal space
– Peritoneal lavage– Bladder irrigation – Alternating all three active internal rewarming
modalities between two Infuser chambers allowing dwell time for all 3 modes
– Maximum outflow temp from Infuser approx 41C
Case
• Meanwhile…– Team leader calls Trauma Centre intensivist re:
transfer for CPB– Intensivist unclear as to whether CPB warranted
in this case and states “will call back”– Aggressive rewarming continues to produce a
rise to 28.5C after 30 minutes– Intensivist calls back to recommend rapid
transport for CP bypass – Patient transported by ground (now dark
outside) to nearest Trauma Centre
Case
– CPB initiated– Patient rapidly warms with return of
spontaneous circulation– Proceeds to develop MODS that
results in death shortly after
Issues from Case
• Resuscitation of hypothermic patient:– CPR– ACLS– Defibrillation– Medications
• Core temperature measurement• Rewarming methods, rates, logistics
and their indications• Prognostic markers of death in
hypothermia
Definitions
• Temperature < 35 C– Mild 32-35 C– Moderate 28-32 C– Severe < 28 C
• Primary (cold exposure) • Secondary (disease process, eg. Myxedema)• Acute (rural, outdoor hypothermia)• Chronic (urban, indoor, elderly hypothermia)• Immersion vs. non-immersion (degree of
rapidity)
Epidemiology
• 723 deaths per year US 1979-1995• 50% older than 65• Male:female 3:1• Socioeconomic factors• Mentally ill 5 times greater risk
Mechanisms of Heat Loss
Mechanism Approximate % of Heat Loss
Radiation 50
Convection 30
Evaporation 15
Conduction 5
Physiology: Mild
• 37.6 normal rectal temperature• 37.0 normal oral temperature• 36.0 ↑ metabolic rate, bp, and muscle
tone• 35.0 maximum shivering • 34.0 amnesia, poor judgment • 33.3 Ataxia, apathy; cold diuresis
Danzl DF. Accidental hypothermia. Wilderness Medicine
Physiology: Moderate
• 32.0 stupor• 31.0 shivering stops• 30.0 poikilothermia; arrhythmias
develop• 29.0 ↓ LOC, HR and RR; dilated pupils
Danzl DF. Accidental hypothermia. Wilderness Medicine
Physiology: Severe
• 28.0 ↓ VF threshold; hypoventilation• 26.0 no response to pain• 25.0 cerebral autoregulation fails,
spontaneous VF and asystole• 24.0 hypotension and bradycardia• 23.0 areflexic (incl. corneal and doll’s
eye)• 22.0 max VF riskDanzl DF. Accidental hypothermia. Wilderness Medicine
Physiology: Profound
• 20.0 lowest resumption of cardiac activity
• 19.0 EEG silent• 13.7 lowest adult accidental
hypothermia survivor Gilbert et al. Resuscitation from accidental hypothermia of 13.7oC with circulatory arrest. Lancet 355: 375, 2000.
• 9.0 lowest therapeutic hypothermia survivor Niazi et al. Profound hypothermia in Man: Report of a case. Annals of surgery. 147(2): 26466, 1958.
Danzl DF. Accidental hypothermia. Wilderness Medicine
Causes of Hypothermia1. Decreased Heat
Production– Neuromuscular
inefficiency• Impaired shivering• Age• Immobility / inactivity
– Endocrine failure• Hypopit• Hypothyroid• Adrenal insuff
– Nutritional• Hypoglycemia• Anorexia• Malnutrition
2. Increased Heat Loss– Exposure / Immersion– Dermatologic
• Erythroderma• Burns / TENS• Psoriasis)
– Vasodilation• ETOH• Toxins
– Iatrogenic• Emergent deliveries• Cold infusion
Hanania, NA et al. Accidental Hypothermia. Critical Care Clinics. 15(2): 236-49, 1999
Causes of Hypothermia
3. Impaired Thermoregulation – Drugs
• Sedatives• Barbiturates• EtOH• TCA
– Peripheral neuropathy– SCI– DM– CNS bleed / trauma– Parkinson's– Anorexia nervosa
4. Miscellaneous– Sepsis– Pancreatitis– Carcinomatosis– Uremia– Vascular insufficiency
Hanania, NA et al. Accidental Hypothermia. Critical Care Clinics. 15(2): 236-49, 1999
Diagnosis
• High index of suspicion• Low reading thermometer
Temperature measurement
• Need an accurate approximation of core temperature
• Traditionally rectal (at least 10-15cm)• Rectal temperature lags behind core:
especially during rapid change, cooling to warming transition(Terndrup TE. An appraisal of temperature assessment by infrared emission detection tympanic thermometry. Ann Emerg Med 21:1483-1492, 1992)
Temperature measurement
• Direct tympanic thermometry is research standard, but not convenient for ER use
• Indirect infrared tympanic thermometry:– often doesn’t read below 34oC– Susceptible to cerumen or water in
the canal
Temperature measurement
• Esophageal– Falsely elevated with heated inhalation
• Bladder– Falsely elevated with peritoneal lavage– Falsely low with cold diuresis
• Oral– Found to be comparable to tympanic probe
in “hypothermic” trauma patients 35.2-35.6Kober A et al. Effectiveness of resistive heating compared with passive warming in treating hypothermia
associated with minor trauma: a randomized trial. Mayo Clin Proc;. 76:369-75, 2001.
Diagnosis: Lab
• ABG’s:– Controversy of historical interest only– Curve shifts left with colder temps causing
pH to be reported lower and O2, CO2 to be reported as higher than actual
– Blood gas analyzer runs samples at 37oC– Current consensus is that use of uncorrected
values provides better outcomesCorneli HM. Environmental Emergencies. Clinical Pediatric Emergency Medicine. 2(3):179-91, 2001.
Lab
• Coags may be reported as normal if run at 37oC despite obvious clinical coagulopathy
• Electrolyte abnormalities are common and should be addressed
• Hypoglycemia should be treated
ECG
The J or Osborne Wave
• Deflection of the J point: the junction of the QRS complex and ST segment
• Most common in leads II and V6• Diagnostic but not prognostic• Not pathognomonic: can also occur in CNS
lesions, focal cardiac ischemia and sepsis• Magnitude of J wave inversely correlates
with temperature Susi U et al. A prospective evaluation of the electrocardiographic manifestations of hypothermia. Academic Emergency Medicine: 6(11); 1121-26, 1999.
Other ECG findingsMattu A et al. Electrocardiographic Manifestations of Hypothermia. American
Journal of Emergency Medicine. 20(4); 314-26
• Artifact produced by clinically invisible preshivering muscle tone may obscure P waves
• Any arrhythmia (atrial or ventricular) is possible
• Bradycardia, Afib, VF asystole common• Treatment of Afib with anticoagulants has not
been studied and should not be undertaken• ECG changes resembling ischemia can occur
and should only be treated with rewarming
Basic Management: ABC’s
• A/B:– Supplemental O2, consider ETT– Neuromuscular blocks ineffective < 30 C– May have to use nasotracheal approach if rigid – Unlikely to induce arrhythmias with ETT
• C:– Continuous monitoring; usually volume depleted– Peripheral lines ideal; Central may precipitate dysrythmias– Avoid PA catheters under 32 C – Bolus in 250-500 cc increments with glucose checks and
5% dextrose if necessary– Theoretically avoid ringers lactate due to impaired liver– <32 C all fluids warmed to 40 to 42 C
Basic Management: ABC’s
• Remove wet clothing• Avoid rough movement as this
may precipitate VF• Nasogastric tube to relieve
distension• Foley for monitoring
ACLS in Hypothermia2000 AHA Guidelines
• For absent pulse or respirations– Start CPR– Defibrillate VF/Pulseless VT with
MAXIMUM of 3 shocks 200, 300, 360– Secure airway, ventilate with warm
humidified oxygen, start IV with warmed NS
ACLS in Hypothermia2000 AHA Guidelines
• For core temperature>30oC– CPR– IV meds as per ACLS but with
extended dosing intervals– Repeats defibrillation attempts as
temp rises
ACLS in Hypothermia2000 AHA Guidelines
• For core temperature<30oC– CPR– Withhold IV meds– No further shocks– Proceed with active rewarming
CPR
• Can be difficult due to chest wall inelasticity
• Optimal rate unknown• Tissue decomposition, rigor
mortis, fixed and dilated pupils are NOT indications to withhold CPR
Defibrillation
• Hypothermia is known to alter ion channel function and hence alter defibrillation efficacy
• Several case reports suggest hypothermia impairs defibrillation leading to traditional belief that defibrillation is largely ineffective below 28oC
Defibrillation
• Case reports of hypothermic VF responsive to defibrillation do exist:– Thomas et al. Successful defibrillation in profound
hypothermia. Resuscitation. 47(3): 317-20, 2000.• Successful defibrillation of hypothermic patient with core body
temperature of 25.6oC
– Cortes et al. Severe accidental hypothermia: rewarming by total cardiopulmonary bypass. Revista Espanola de Anestesiologia y Reanimacion. 41(2):109-12, 1994.
• 20-year-old male with profound hypothermia (26oC presented in deep coma with recurring ventricular fibrillation that yielded to electrical defibrillation once a core temperature of 27.4oC was reached
DefibrillationUjhelyi et al. Defibrillation energy requirements and electrical heterogeneity during
total body hypothermia. Critical Care Medicine: 29(5), 2001.
• Animal study• Compared normothermia with
hypothermia of 30oC• Induced brief VF• No change in defibrillation energy
requirements in hypothermia• Fibrillatory threshold noted to be
reduced
Defibrillation
• Bottom Line:– Attempt a maximum of three shocks
at standard energy settings (200J, 300J, 360J) in the hypothermic VF or pulseless VT patient with core body temperature below 30oC
Pacing?Dixon et al. Transcutaneous pacing in a hypothermic dog model. Annals of
Emergency Medicine. 29(5): 602-6, 1997.
• 20 mongrel dogs core temperature of 27oC
• TCP restored and maintained hemodynamic stability and allowed the hypothermic animals to rewarm in half the time required by their nonpaced counterparts
• No human studies
Medications in Hypothermic Arrest
• Generally reported to be ineffective and possibly even harmfulCorneli HM. Environmental Emergencies. Clinical Pediatric Emergency Medicine. 2(3):179-91, 2001.
• Bretylium, lidocaine, vasopressors all studied with no consensus
• Kornberger et al. Effects of epinephrine in a pig model of hypothermic cardiac arrest and closed-chest cardiopulmonary resuscitation combined with active rewarming. Resuscitation. 50(3):301-8, 2001.– Epinephrine did not improve time to spontaneous
perfusion, and even worsened mixed venous hypercarbic acidosis.
Medications in Hypothermic Arrest
• Bottom line:– Avoid in core temp <30oC
Rewarming Methods: Issues
• Severe hypothermia is uncommon• No RCT’s exist in accidental hypothermia• Evidence is primarily from case reports• Rapid rewarming, while intuitive, has
never been proven to improve outcomes• Human experimental model unethical
below 35oC• Risky to blindly generalize results of
animal studies to humans
Rewarming Methods: Issues
• Rigid treatment protocols are inherently hazardous
• Clinical circumstances and availability of resources have to be taken into account
Core Temperature Afterdrop
• The continued decline in a hypothermic patient’s temperature after removal from the cold
• Cause is temperature equilibration between the warmer core and cooler periphery and countercurrent cooling of blood perfusing the cold extremities
• Ideally, rewarming strategies would avoid significant afterdrop
Rewarming Methods
1. Passive external rewarming2. Active rewarming
1. Active external rewarming2. Active core rewarming
Passive External Rewarming
• Involves covering patient with insulating material to prevent further heat loss
• Indicated mainly for mild hypothermia or as an adjunct in moderate to severe hypothermia
• Patient must have endogenous thermogenesis– Humans are poikilothermic below 30oC– Shivering stops below 32oC
• Rewarming rates in mild hypothermia with PER range from 0.5-2.0oC/hrHanania et al. Accidental Hypothermia. Critical Care Clinics. 15(2):236-48, 1999
Active Rewarming
• Direct transfer of exogenous heat to the patient
• Internal or external techniques• Indications:
– Poikilothermia (T< 32oC)– Cardiovascular instability– Inadequate rate or failure to rewarm– Endocrine insufficiency– Traumatic or toxicologic peripheral vasodilation– Secondary hypothermia impairing thermoregulation– Neonatal or infant patients
Active External Rewarming
• Exogenous heat is delivered directly to the skin
• Forced air rewarming• Warming blankets or heating pads• Immersion • Arteriovenous anastomoses
rewarming
Forced Air Rewarming
• e.g. Bair Hugger• Theoretical concern: vasodilation
in extremities could transport cooler blood back to core causing afterdrop and rewarming shock
• Advantages: easy to use, readily available, low cost, noninvasive
Forced Air Rewarming
• Has been used successfully in accidental hypothermia (including profound) without evidence of afterdrop or rewarming shock
• Usually in conjunction with warmed IV fluids and heated inhalation
• Rewarming rates between 1 to 4.4oC/hr
De Caen, A. Management of profound hypothermia in children without the use of extracorporeal life support therapy. The Lancet. 360:1394-95, 2002.
Koller R, Schnider TW, Neidhart P: Deep accidental hypothermia and cardiac arrest--rewarming with forced air. Acta Anaesthesiol Scand 41:1359, 1997
Roggla et al. Severe accidental hypothermia with or without hemodynamic instability: rewarming without the use of extracorporeal circulation. Wiener Klinische Wochenschrift. 114(8-0):315-20, 2002
Steele et al. Forced air speeds rewarming in accidental hypothermia. Ann Emerg Med. 27:479, 1996
Immersion
• Impractical in ER setting• Makes monitoring and CPR
impossible
Arteriovenous Anastomoses Rewarming
• Originally described by Vangaard in 1979• Exogenous heat provided by immersion of
lower parts of extremities (hands, feet, forearms and calves) in 44-45oC water
• Mechanism: – Heat opens arteriovenous anastomoses that exist
1mm below epidermal surface in digits– Results in increased flow of warmed venous SC
blood returning to heart– Countercurrent heat loss is minimized as superficial
veins are distant from arteries
• Theoretically should minimize afterdrop
Vanggaard L et al. Immersion of distal arms and legs in warm water (AVA
rewarming) effectively rewarms mildly hypothermic humans. Space and
Environmental Medicine. 70(11):1081-8, 1999
• Voluntary mildly hypothermic subjects warmed comfortably with AVA technique at a rate of 9.9+/-3.2 degrees C with minimal afterdrop
Diathermy
• Experimental technique involving transmission of heat by ultrasonic and low frequency microwave radiation
• Animal studies promising
Active Core Rewarming
• Heated inhalation• Heated infusion• Lavage
– Gastric– Colonic– Mediastinal– Thoracic– Peritoneal– Bladder
• Hemodialysis• Extracorporeal methods
Heated Inhalation
• Must be humidified as dry air has little thermal conductivity
• 40-45oC• Although rewarming rates have
been reported at 1-2.5oC/hr, primary aim is to reduce respiratory heat loss
Warmed IV Fluids
• Cold fluid resuscitation is well known to induce hypothermia in previously normothermic trauma patientsKashuk et al. Major abdominal vascular trauma: a unified approach. J trauma. 22:672, 1982
• Heat IV fluids to 40-42oC• Conductive heat loss is significant
through long IV tubing esp. at low rates• Level 1 Fluid Warmer ideal• In theory, 1 L of fluid at 42oC should
warm a 70kg patient at 28oC by 0.33oC
Warmed IV Fluids
• New research into superheated fluids at 65oC
• Central infusion• Animal studies• No apparent complications• More work needs to be done
Fildes et al. Very hot intravenous fluid in the treatment of hypothermia. J trauma. 35:683, 1993.Sheaff et al. Safety of 65oC intravenous fluid for the treatment of hypothermia. Am J Surg. 172:52, 1996.
Heated Irrigation
• Gastric, colonic, bladder– Limited surface area for heat transfer– Gastric lavage may be complicated by
aspiration– Average rewarming rates of 1.5-2oC/hr
Hanania et al. Accidental Hypothermia. Critical Care Clinics. 15(2):236-48, 1999
Danzl DF. Accidental hypothermia. Wilderness Medicine
Peritoneal Lavage
• 40-45oC dialysate via minilaparotomy or percutaneous puncture
• Flow rates of ~6 L/hr• Rewarming rates of 1-3oC/hr• Electrolytes must be carefully
monitored
Closed Thoracic Lavage
• Procedure:– Two 36-40F thoracostomy tubes placed in
one or both hemithoraces– Anterior second or third intercostal space at
midclavicular line– Posterior axillary line at fifth to sixth
intercostal space– Infuse NS at 40-42oC into anterior tube,
drain by suction or gravity from posterior tube
Closed Thoracic Lavage
• Potentially hazardous in the non-arrest patient (precipitate VF)
• Clinical experience is limited• Rewarming rates average 3-6oC /hr• Ensure adequate drainage or tension
hydrothorax will ensue
Kangas et al. Treatment of hypothermic circulatory arrest with thoracotomy and pleural lavage. Annales Chirurgiae et Gynaecologiae. 83(3):258-60, 1994.
Winegard C. Successful treatment of severe hypothermia and prolonged cardiac arrest with closed thoracic cavity lavage.] Journal of Emergency Medicine. 15(5):629-32, 1997.
Danzl DF. Accidental hypothermia. Wilderness Medicine. P159.
Mediastinal Irrigation
• Standard left thoracotomy• Irrigation of mediastinum with 40oC fluid• Also allows for direct cardiac compression
and direct defibrillation• Only indicated in cardiac arrest• One uncontrolled, nonrandomized review
reported favourable results with ED thoracotomy +/- CPB compared to immediate CPB aloneBrunette et al. Hypothermic cardiac arrest: an 11 year review of ED management and outcome. Am J Emerg Med. 18(4): 418-22, 2000.
Extracorporeal Rewarming
• Hemodialysis• Arteriovenous rewarming• Venovenous rewarming• Cardiopulmonary bypass
Extracorporeal Rewarming
• Complications– Vascular injury– Air embolism– Pulmonary edema– Coagulopathy
• Contraindications– DNR order or obviously lethal injuries present– Lack of venous return– Intravascular clots or slush
Hemodialysis
• Best for stable patients with renal failure or dialyzable toxin
• Has been reported in the literature in a known dialysis patient who suffered cold exposure leading to core temp or 24.9oC. Warmed hemodialysis was performed for an average temperature rise of 1.9oC/hrOwda A. Osama S. Hemodialysis in management of hypothermia. American Journal of Kidney
Diseases. 38(2):E8, 2001 Aug
Arteriovenous Rewarming
• Femoral artery and contralateral femoral venous catheters
• Countercurrent fluid warming• Required SBP>60mmHg• Heparinization• Rates of 3-4oC/hr
Venovenous Rewarming
• Countercurrent fluid warming with roller pump
• Warmed blood is removed from central line then returned by a second IV site
• No circulatory support
Cardiopulmonary Bypass
• Considered gold standard of rewarming hypothermic arrest patients
• Preserves oxygenated flow in patients without mechanical cardiac activity
• Fastest of all rewarming strategies at 1-2oC every 3 to 5 minutes!!!
Cardiopulmonary Bypass
• Can be lifesaving in cases of profound hypothermia with prolonged arrest times– Walpoth et al 1997: 32 arrest patients with mean
T=21.8 rewarmed with CPB. 15 long term survivors– Schwarz et al 2000: 5 arrest patients treated with CPB,
2 survived– Gilbert et al 2000: 1 arrest patient T=13.7, warmed
with CPB, survived– Althaus et al 1982: 3 severely hypothermic patients
treated with CPB: all recovered – Vretnar et al 1994: 68 hypothermic patients (61 arrest)
mean T=21 placed in CPB. 60% survived– Koller et al 1997: 5 patients (2 arrest) on CPB, all
survived
Cardiopulmonary Bypass
• Standard femoral artery-femoral vein CPB includes vascular catheters, mechanical pump, membrane or bubble oxygenator and heat exchanger
• Heparin-coated perfusion equipment has been developed and used successfully in patients with contraindications to heparinization
“No one is dead until they are warm and dead”
Prognostic Markers
• Survival is difficult to predict• Literature is littered with case reports of
dramatic saves• Mortality rate in severe hypothermia 40-75%• Wide variation in human physiologic
responses to hypothermia• Accurate triage markers of death are needed• No validated prognostic indicators in the
literature
Mair et al. Prognostic markers in patients with severe accidental
hypothermia and cardiocirculatory arrest. Resuscitation; 27:47-54,
1994• Retrospective study of 22 patients with severe
hypothermia and cardiac arrest treated with CPB• Found that in avalanche victims
– K>9 mmol/L– pH<6.50 (central venous)– Activated clotting time>400s
Were not compatible with re-establishment of circulation
• Results could not be applied to non-avalanche causes of hypothermia
Schaller et al. Hyperkalemia: a prognostic factor during acute
severe hypothermia. JAMA; 264: 1842, 1990.
• Retrospective review of 9 hypothermic avalanche victims and 15 hypothermic intoxications
• All avalanche victims were hyperkalemic (6.8-24.5) and none survived
• All intoxications were not hyperkalemic (2.7-5.3) and all survived
Segesser et al. Perfusion without systemic heparinization for
rewarming in accidental hypothermia. Ann Thoracic Surg.
52:560-561, 1991.
• Reports resuscitation of hypothermic patient with K=9.5 mmol/L
Wollnek et al. Cold water submersion and cardiac arrest in treatment of severe hypothermia
with cardiopulmonary bypass. Resuscitation; 52(3):255-63, 2002.
• Base excess, pH, K– Not reliable prognostic markers
Bottom Line
• Decision to continue or terminate resuscitative efforts in hypothermic arrest patients cannot at this time be based on lab values
• May be useful to guide judgment in situations of multiple victims with limited resources
CHR Protocol
• Mild hypothermia>32oC– External passive rewarming
• Warm blankets and environment
– External active rewarming:• Forced air warming blanket
– Internal rewarming• Warm IV fluids (<45oC)
CHR Protocol
• Moderate hypothermia 28-32oC with stable hemodynamics– External active rewarming:
• Forced air warming blanket
– Internal active rewarming:• Warm IV fluids• Consult ICU re:
– Warmed humidified ventilation– Hemodialysis with warm dialysate (esp if
intoxication suspected)
CHR Protocol
• Severe hypothermia <28oC or <32oC with unstable hemodynamics– Trauma team activation, Level 1– Consult CV surgery team:
• Surgeon, nursing staff, anesthetist, perfusionist and OR, anesthesia tech at 0050
• Take to trauma OR
CHR Protocol
• Severe hypothermia continued: hemodynamically stable– External active rewarming
• Forced air warming blanket
– Internal active rewarming• Warm IV fluids• Warmed humidified ventilation• Warmed peritoneal lavage• Place percutaneous femoral arterial and venous
catheters for extra-corporeal support access in case of hemodynamic deterioration
• If neurologic or other major bleeding injury ruled out, consider CPB even if stable with T<28oC
CHR Protocol
• Severe hypothermia continued: hemodynamically unstable: VT, VF, asystole– ACLS protocol– CPR– 1 series of 3 defibrillations at T<30oC – Withhold other rewarming strategies while
awaiting extra-corporeal support– Place percutaneous arterial and venous
cannulae if vessels accessed pre-arrest or cutdown if post-arrest
CHR Protocol
• Bypass protocol for severe hypothermia– Neurologic injury suspected
• Establish ECMO– Minimal dose heparin 0-3000U at time of cannulation– Heparin bonded extracorporeal circuit and oxygenator– Arterial and venous cannulae are not heparin bonded:
avoid stasis– Biomedicus pump– Heat exchanger– Heparin – ACT management: risk/benefit– Continue CPR until circulation established
CHR Protocol
• Bypass protocol for severe hypothermia– Neurologic injury not suspected
• Regular cardio-pulmonary bypass with full heparinization
• With femoral cannulation, LV decompression may be inadequate: continued CPR may be required until perfusing rhythm re-established
• Sternotomy for difficult femoral access and pediatric patients
Questions?
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