pes to set peep- the american approach - critical care …€¦ · · 2017-11-102 0) 6 ml/kg...
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Pes to set PEEP-
The American Approach
Patient Engagement, Systems Science, and the Elimination of Preventable Harm
Daniel Talmor, MD, MPH
ARDS Patient
• Post traumatic ARDS
• 46 y/o male s/p MVC, fractured pelvis
• Compromise of circulation to the legs
• Anasarca and a tense abdominal wall
• Initial ventilator settings
– CMV
– TV= 535 cc
– Fi02= 1
– PEEP= 13
Animal Experiments Show That Adequate PEEPCan Reduce VILI
• Faridy et al. – Large volume mechanical ventilation increased surface tension
– At a given VT, effect attenuated by higher PEEP
• Wyszogrodski et al. – High volume ventilation inactivated surfactant in cats
– At a given VT, effect less with higher PEEP
• Webb and Tierney – High volume ventilation caused hemorrhagic edema and hyaline membranes in rats
– At constant peak pressure, effect less with higher PEEP
• Muscedere et al. – Even low volume ventilation in lavaged rat lungs caused histological damage.
– Effects were reduced or eliminated with higher PEEP.
• Chiumello et al. – Ventilation of injured rat lungs released inflammatory cytokines.
– At a given VT, effects were less with higher PEEP.
ALVEOLI Trial
• ALVEOLI- higher vs. lower levels of PEEP based on tables- Day 1 PEEP- 8.9 vs. 14.7 cm H2O .
• Stopped early for futility
• No benefit in rates of death before hospital discharge in either group
Lower PEEPHigher Fi02
Higher PEEPLower Fi02
Brower, NEJM 2004.
Further Trials
• Amato demonstrated a benefit to a low tidal volume
strategy combined with PEEP set by LIP of the PV
curve.
• ARIES trial seemed to confirm this
• LOVS trial showed no benefit.
• The EXPRESS trial which set PEEP based on the
airway plateau pressure showed mixed results
“The LOV study and the Express study not only should conclude the era of comparing PEEP levels in unselected populations with
ALI and ARDS, but also underscore the need for a new definition of ARDS aimed at
identifying patients with greater lung edema and larger recruitability …”
Gattinoni L, Caironi P; JAMA. 2008
Briel M, JAMA, 2010; 303: 865
Vent
PL = Pao - PPlPao
PPl
Lung
Chest Wall
PL is the pressure actually distending the lung.
This may be very different from the pressure measured at the airway.
PL May be more important then Pao
Vent
PL = Pao - PPlPao
PPl
Lung
Chest Wall
Titrating ventilation based on ventilator pressures does not allow us to take this variability into account
PL May be Very Different then Pao
Pleural Pressure MeasurementPulmonary vs Non-pulmonary ARDS
Gattinoni, AJRCCM 1998
Esophageal Pressure to Estimate Pleural Pressure
Mechanical ventilation: passive
Pes
Volume
Volume
0 25
P-V curveof passiveChest Wall
Pes (cmH2O)
Pressure transducing wafers implanted in dog lungs revealed differences in pleural pressure due to the gravitational effect of the dependant vs. non-dependant regions of the lung.
Pes Values Reflect High Pleural Pressures
-7
+4
Pes 0
Non-Dependant
Mid-Lung
Dependant
Pelosi AJRCCM 2001
In Humans
Talmor et al. CCM 2006
Pes Ranges Widely in Patients with ALI
Transpulmonary and Airway Pressure
Talmor et al. CCM 2006
Sample Data from Anesthetized Obese Subject
Paw
Pes
Vol.
Flow
31 sec
Threshold Paw
Expanded Time Scale
Paw
Pes
Vol.
Flow
6 sec.
PT 1 Initial Ventilator settings on PCV
Paw
-10
50
0
Pes
PL
50
040
Paw = 13 to 40
Pes = 20 to 33
Ptp = -8 to 6
Ventilator pressures:
PEEP 13 26
which raised
Pplateau 40 46
Pt 1 Strategy: Change ventilator pressures to optimize PL
Pt 1 After Ventilator Changes to Optimize PL
Paw
-10
50
0
Pes
PL
50
040
Paw = 26 to 46
Pes = 22 to 33
Ptp = 4 to 12
Ventilator pressures:
PEEP 13 26
Pplat 40 46
Driving pressure: 27 20
Pt 1 Strategy: Change Ventilator Pressures to Optimize PL
Talmor D, N Eng J Med, 2008; 359:2095
Talmor D, N Eng J Med, 2008; 359:2095
6- Month Survival
N001 Baseline
17 cmH2OPao
Flow
Pes
Ptp
28 cmH2O
-11 cmH2O
N001 Day 1
33 cmH2OPao
Flow
Pes
Ptp
34 cmH2O
-0.8 cmH2O
25 23 21 19 17 15 13 11 9 7 5
0
10
20
30
40
50
60
-10
-5
0
5
10
15
20
25
30
PEEP (cmH2O)
EIT
Co
lla
ps
e (%
)Baseline
EIT CollapsePtpE absolute
PtpE calculated Ptp
E (c
mH
2 O)
PL and EIT
Fumagalli, ATS 2016
25 23 21 19 17 15 13 11 9 7 5
0
10
20
30
40
50
60
-10
-5
0
5
10
15
20
25
30
PEEP (cmH2O)
EIT
Co
lla
ps
e (%
)Obese
EIT CollapsePtpE absolute
PtpE calculated Ptp
E (c
mH
2 O)
PL and EIT
Fumagalli, ATS 2016
Optimal Risk/Benefit of PEEP May Depend on Recruitability
0
10
20
30
P=0.566 ml/kg
6 ml/kg
Pplat
Driving Pressure
PEEP(cm H20)
6 ml/kgNon-
recruitable 6 ml/kgRecruitable
Injury >Benefit
Benefit>Injury
Lower PEEP
Higher PEEP
Pes to set PEEP-
The American Approach
Patient Engagement, Systems Science, and the Elimination of Preventable Harm
Daniel Talmor, MD, MPH