Mask Use and Ventilation Improvements to Reduce COVID-19 ...
Basics of Mechanical Ventilation for the COVID-19 Patient€¦ · Basics of Mechanical Ventilation...
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Hooman Poor, M.D. Assistant Professor of Medicine Director of Pulmonary Vascular Disease, Mount Sinai-National Jewish Health Respiratory Institute Division of Pulmonary, Critical Care and Sleep Medicine Zena and Michael A. Wiener Cardiovascular Institute Icahn School of Medicine at Mount Sinai Basics of Mechanical Ventilation for the COVID-19 Patient
Transcript of Basics of Mechanical Ventilation for the COVID-19 Patient€¦ · Basics of Mechanical Ventilation...
HoomanPoor,M.D.AssistantProfessorofMedicine
DirectorofPulmonaryVascularDisease,MountSinai-NationalJewishHealthRespiratoryInstituteDivisionofPulmonary,CriticalCareandSleepMedicineZenaandMichaelA.WienerCardiovascularInstitute
IcahnSchoolofMedicineatMountSinai
BasicsofMechanicalVentilationfortheCOVID-19Patient
Financial Disclosures
None
Talk Objectives
• discusstherationaleofpositivepressureventilationforpatientswithARDSsecondarytoCOVID-19
• reviewthebasicsofvolume-controlledventilation
• explainhowtosetandadjusttheimportantparametersinvolume-controlledventilationforCOVID-19patientswithARDS
COVID-19 Causes ARDS
ARDSDefinition:• acute• bilateralopacities• PaO2/FIO2ratio<300mmHgwithPEEP≥5cmH2O
• notcompletelyexplainedbycardiacfailureorvolumeoverload
ARDS Pathophysiology • lunginjuryandinflammationcreateleakycapillariesandleakyalveoli
• alveolifillupwithfluid• gasexchangeimpaired• alveolicollapse• lungsbecomestiffer• patientsultimatelydeveloprespiratoryfailure
Thompson,NEJM2017
Ventilator Support in ARDS
• deliverhighamountsofoxygen- highFIO2
• providepositivepressuretoreduceworkofbreathing
- ventilatorPUSHESairinsomusclesofinspirationdonothavetoworkashardtoSUCKairin
• providepositiveend-expiratorypressure(PEEP)
- preventsopenalveolifromcollapsing
How to Inflate Lungs
êPpl
éPalv
Palv=alveolarpressurePpl=pleuralpressure
a) increasepressureinsideofthelungs(Palv)
b) decreasethepressureoutsideofthelungs(Ppl)
Poor,BasicsofMechanicalVentilation,2018
spontaneousventilation
Poor,BasicsofMechanicalVentilation,2018
spontaneousventilation
positivepressureventilation
Poor,BasicsofMechanicalVentilation,2018
Poor,BasicsofMechanicalVentilation,2018
Poor,BasicsofMechanicalVentilation,2018
Pair=proximalairwaypressurePalv=alveolarpressureQ=flowR=resistance
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
Poor,BasicsofMechanicalVentilation,2018
Pair=proximalairwaypressurePalv=alveolarpressureQ=flowR=resistance
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
spontaneousventilation
Suckairintolungs
Poor,BasicsofMechanicalVentilation,2018
Pair=proximalairwaypressurePalv=alveolarpressureQ=flowR=resistance
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
positivepressureventilation
Pushairintolungs
Regardless of the mode of ventilation...
• theventilatorincreasesairwaypressureforasettime
- airflowintothepatient- culminatesindeliveredtidalvolume
• “phasevariables”determinethemodeofventilation- ventilatorinstructions- determine“when”and“how”breathsdelivered
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
Phase Variables: “Anatomy of a Breath”
• triggeràwheninspirationbegins• targetàhowflowisdeliveredduringinspiration• cycleàwheninspirationends• baselineàproximalairwaypressureduringexpiration
Poor,BasicsofMechanicalVentilation,2018
Modes of Ventilation
trigger
target
cycle
Forthesakeofsimplicity,use
volume-controlledventilation(VCV)
WhatmodeofventilationshouldIuse?
Trigger
• Whoinitiatesthebreath?- ventilator- patient
• ventilator-triggered- akaCONTROL- variablethatissetàtime- setrespiratoryrate(frequency=1/time)- RR12bpmisonebreathevery5seconds
• patient-triggered- akaASSIST- floworpressurechangessensedbyventilator
Assist-Control à Hybrid Trigger
• assisttrigger+controltrigger=assist-control(A/C)
“A/C”refersonlytothetrigger.
Volume-controlledventilationusesA/Casthetriggermechanism.
How Much Assist? How Much Control?
controlrespiratoryrate neuralrespiratoryrate-10bpm-breathevery6sec
-20bpm-breathevery3sec
Whatpercentageofthebreathswillbeassist,whatpercentagewillbecontrol?
100%ASSISTControlrateclockresetsafteran“assist”breath.
How Much Assist? How Much Control?
controlrespiratoryrate neuralrespiratoryrate-10bpm -20bpm
-breathevery3sec
How Much Assist? How Much Control?
controlrespiratoryrate neuralrespiratoryrate-30bpm-breathevery2sec
-20bpm-breathevery3sec
Whatpercentageofthebreathswillbeassist,whatpercentagewillbecontrol?
100%CONTROL
controlrespiratoryrate
lastbreathwasa“control”breath
actualrespiratoryrate
Target
Howisflowduringinspirationdetermined?- flowrateissetinvolume-controlledventilation
Poor,BasicsofMechanicalVentilation,2018
deceleratingrampshape
peakinspiratoryflowrate
VCV is a Flow-Targeted Mode
VCV is a Flow-Targeted Mode
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
Qwillnotchangewithchangesinrespiratory
system
Pairwillchangewithchangesinrespiratorysystem
pressurewaveform
peakpressure
Target
Poor,BasicsofMechanicalVentilation,2018
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
bitingendotrachealtube
flowunchanged flow-targetedmode
Target
Poor,BasicsofMechanicalVentilation,2018
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
𝑄= 𝑃↓𝑎𝑖𝑟 − 𝑃↓𝑎𝑙𝑣 /𝑅
sustainedinspiratoryeffort
flowunchanged flow-targetedmode
Cycle
Whendoesinspirationend?- volumeissetinvolume-controlledventilation
Poor,BasicsofMechanicalVentilation,2018
tidalvolume
exhaledtidalvolumereturningtoventilator
Low Tidal Volume Ventilation
• hightidalvolumeinARDScauseslungstretchandfurtherlungdamage
- “volutrauma”
• lowtidalvolumeventilationisessential- settidalvolumeto6cc/kgofidealbodyweight- canbeuncomfortableforpatients(willlikelyneedsedation,andsometimesevenparalysis)
Baseline
• Whatisproximalairwaypressureduringexpiration?
• akaPEEP
Poor,BasicsofMechanicalVentilation,2018
PEEP in ARDS
• repetitiveopeningandclosingofalveolicausesfurtherlungdamage
- “atelectrauma”
• PEEPpreventsopenalveolifromclosing
• maintainingalveoliopenwillimprovegasexchange
INCLUSION CRITERIA: Acute onset of 1. PaO2/FiO2 ≤ 300 (corrected for altitude) 2. Bilateral (patchy, diffuse, or homogeneous) infiltrates consistent with
pulmonary edema 3. No clinical evidence of left atrial hypertension PART I: VENTILATOR SETUP AND ADJUSTMENT 1. Calculate predicted body weight (PBW)
Males = 50 + 2.3 [height (inches) - 60] Females = 45.5 + 2.3 [height (inches) -60]
2. Select any ventilator mode 3. Set ventilator settings to achieve initial VT = 8 ml/kg PBW 4. Reduce VT by 1 ml/kg at intervals ≤ 2 hours until VT = 6ml/kg PBW. 5. Set initial rate to approximate baseline minute ventilation (not > 35
bpm). 6. Adjust VT and RR to achieve pH and plateau pressure goals below.
AARRDDSSnnee tt OXYGENATION GOAL: PaO2 55-80 mmHg or SpO2 88-95% Use a minimum PEEP of 5 cm H2O. Consider use of incremental FiO2/PEEP combinations such as shown below (not required) to achieve goal. Lower PEEP/higher FiO2
FiO2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.7 PEEP 5 5 8 8 10 10 10 12
NIH NHLBI ARDS Clinical Network FiO2 0.7 0.8 0.9 0.9 0.9 1.0 PEEP 14 14 14 16 18 18-24 Mechanical Ventilation Protocol Summary Higher PEEP/lower FiO2 FiO2 0.3 0.3 0.3 0.3 0.3 0.4 0.4 0.5 PEEP 5 8 10 12 14 14 16 16 FiO2 0.5 0.5-0.8 0.8 0.9 1.0 1.0 PEEP 18 20 22 22 22 24 __________________________________________________________ PLATEAU PRESSURE GOAL: ≤ 30 cm H2O Check Pplat (0.5 second inspiratory pause), at least q 4h and after each change in PEEP or VT. If Pplat > 30 cm H2O: decrease VT by 1ml/kg steps (minimum = 4 ml/kg). If Pplat < 25 cm H2O and VT< 6 ml/kg, increase VT by 1 ml/kg until Pplat > 25 cm H2O or VT = 6 ml/kg. If Pplat < 30 and breath stacking or dys-synchrony occurs: may increase VT in 1ml/kg increments to 7 or 8 ml/kg if Pplat remains < 30 cm H2O.
INCLUSION CRITERIA: Acute onset of 1. PaO2/FiO2 ≤ 300 (corrected for altitude) 2. Bilateral (patchy, diffuse, or homogeneous) infiltrates consistent with
pulmonary edema 3. No clinical evidence of left atrial hypertension PART I: VENTILATOR SETUP AND ADJUSTMENT 1. Calculate predicted body weight (PBW)
Males = 50 + 2.3 [height (inches) - 60] Females = 45.5 + 2.3 [height (inches) -60]
2. Select any ventilator mode 3. Set ventilator settings to achieve initial VT = 8 ml/kg PBW 4. Reduce VT by 1 ml/kg at intervals ≤ 2 hours until VT = 6ml/kg PBW. 5. Set initial rate to approximate baseline minute ventilation (not > 35
bpm). 6. Adjust VT and RR to achieve pH and plateau pressure goals below.
AARRDDSSnnee tt OXYGENATION GOAL: PaO2 55-80 mmHg or SpO2 88-95% Use a minimum PEEP of 5 cm H2O. Consider use of incremental FiO2/PEEP combinations such as shown below (not required) to achieve goal. Lower PEEP/higher FiO2
FiO2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.7 PEEP 5 5 8 8 10 10 10 12
NIH NHLBI ARDS Clinical Network FiO2 0.7 0.8 0.9 0.9 0.9 1.0 PEEP 14 14 14 16 18 18-24 Mechanical Ventilation Protocol Summary Higher PEEP/lower FiO2 FiO2 0.3 0.3 0.3 0.3 0.3 0.4 0.4 0.5 PEEP 5 8 10 12 14 14 16 16 FiO2 0.5 0.5-0.8 0.8 0.9 1.0 1.0 PEEP 18 20 22 22 22 24 __________________________________________________________ PLATEAU PRESSURE GOAL: ≤ 30 cm H2O Check Pplat (0.5 second inspiratory pause), at least q 4h and after each change in PEEP or VT. If Pplat > 30 cm H2O: decrease VT by 1ml/kg steps (minimum = 4 ml/kg). If Pplat < 25 cm H2O and VT< 6 ml/kg, increase VT by 1 ml/kg until Pplat > 25 cm H2O or VT = 6 ml/kg. If Pplat < 30 and breath stacking or dys-synchrony occurs: may increase VT in 1ml/kg increments to 7 or 8 ml/kg if Pplat remains < 30 cm H2O.
Use the High PEEP Ladder
• COVID-19patientsappeartobevery“PEEP-responsive”
• donotincreasePEEPabove16cmH2Owithoutguidancefromacriticalcarephysician
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PEEP
FIO2
Plateau Pressure (Ppl) • estimateofthemaximumpressureinthealveolusduringtherespiratorycycle
• tomeasurePpl,performinspiratorypausemaneuver
- aftertidalvolumeisdelivered,expiratoryvalveremainsshutandairdoesnotleavepatient
- pressuremeasuredatendofmaneuveriscalled“plateaupressure”
• highPplcanleadto“barotrauma”- pneumothorax,pneumomediastinum- goalPplinARDSis≤30cmH2O
Plateau Pressure
plateaupressure
Your COVID-19 Patient Just Got Intubated
• placeonvolume-controlledventilation• setrespiratoryrateto20bpm• settidalvolumeto6cc/kgofidealbodyweight• setFIO2to100%• setPEEPto15cmH20• checkplateaupressure(Ppl)
- ifPpl>30cmH2O,reducetidalvolumeto5cc/kg- ifPplstill>30cmH2O,callforhelp
• ensurepatientiswellsedated• checkABGorVBG30minutesaftersettingsadjustedtoensureappropriatepH
- ifpH<7.2,increaseRR(maximumof35bpm)
Your COVID-19 Patient is Improving
• weanFIO2andPEEPaspertheARDSnetladdertoensureSpO288-95%
• waitatleast12hoursbetweenchangesinPEEP
INCLUSION CRITERIA: Acute onset of 1. PaO2/FiO2 ≤ 300 (corrected for altitude) 2. Bilateral (patchy, diffuse, or homogeneous) infiltrates consistent with
pulmonary edema 3. No clinical evidence of left atrial hypertension PART I: VENTILATOR SETUP AND ADJUSTMENT 1. Calculate predicted body weight (PBW)
Males = 50 + 2.3 [height (inches) - 60] Females = 45.5 + 2.3 [height (inches) -60]
2. Select any ventilator mode 3. Set ventilator settings to achieve initial VT = 8 ml/kg PBW 4. Reduce VT by 1 ml/kg at intervals ≤ 2 hours until VT = 6ml/kg PBW. 5. Set initial rate to approximate baseline minute ventilation (not > 35
bpm). 6. Adjust VT and RR to achieve pH and plateau pressure goals below.
AARRDDSSnnee tt OXYGENATION GOAL: PaO2 55-80 mmHg or SpO2 88-95% Use a minimum PEEP of 5 cm H2O. Consider use of incremental FiO2/PEEP combinations such as shown below (not required) to achieve goal. Lower PEEP/higher FiO2
FiO2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.7 PEEP 5 5 8 8 10 10 10 12
NIH NHLBI ARDS Clinical Network FiO2 0.7 0.8 0.9 0.9 0.9 1.0 PEEP 14 14 14 16 18 18-24 Mechanical Ventilation Protocol Summary Higher PEEP/lower FiO2 FiO2 0.3 0.3 0.3 0.3 0.3 0.4 0.4 0.5 PEEP 5 8 10 12 14 14 16 16 FiO2 0.5 0.5-0.8 0.8 0.9 1.0 1.0 PEEP 18 20 22 22 22 24 __________________________________________________________ PLATEAU PRESSURE GOAL: ≤ 30 cm H2O Check Pplat (0.5 second inspiratory pause), at least q 4h and after each change in PEEP or VT. If Pplat > 30 cm H2O: decrease VT by 1ml/kg steps (minimum = 4 ml/kg). If Pplat < 25 cm H2O and VT< 6 ml/kg, increase VT by 1 ml/kg until Pplat > 25 cm H2O or VT = 6 ml/kg. If Pplat < 30 and breath stacking or dys-synchrony occurs: may increase VT in 1ml/kg increments to 7 or 8 ml/kg if Pplat remains < 30 cm H2O.
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Further Reading
AvailablefreeonlineviatheLevyLibrarywebsite
Good Luck!
