ECMO : da dove siamo partiti?

Antonio Pesenti MD

University of Milano BicoccaItaly

A Brilliant Investigator’s Career

• First decade :

– A new method of respiratory extracorporeal support

• Second decade :

– Respiratory Extracorporeal Support : state of the Art

• Third decade :

– Respiratory Extracorporeal Support : History

Buying time with artificial lungs

Zapol WM, Kits RJ, NEJM 1972; 286 (12)

NIH ECMO STUDY

• FAST ENTRY CRITERIA

– PaO2 < 50 mmHg 3 times 1hr interval ( 2 hrs)

– Fi O2 1 - PEEP > 5 cmH2O

• SLOW ENTRY CRITERIA

• PaO2 < 50 mmHg 3 times 6hr interval (12 hrs)

• FiO2 0.6 - PEEP > 5 cm H2O

– OR

• Qs/Qt > 30% at FiO2 1

NIH

• Expected mortality rate was > 65%

• Observed mortality rate was 92%

• Investigators decided to proceed to an additional data collection :

• All ARF patients undergoing positive airway pressure with an FiO2 > .5 for more than 24 hrs

NIH ECMO STUDY

NIH ECMO Trial

0

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0 2 4 6 8 10 12 14

Days From Entry

Su

rviv

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ECMO

Zapol WM: JAMA 1979; 242: 2193-6

From Conrad SA slide on internet

Ted Kolobow MD

Why Did ECMO Fail?

• Severely diseased lungs have a chance to heal only if the environment remains conducive to the healing of the lungs.

• This environment does not consist of high airway pressures, high tidal volumes, high PEEP, high FiO2…..

Luciano Gattinoni, MD

From Oxygenators:Buying time with artificial lungs

Zapol WM, Kits RJ, NEJM 1972; 286 (12)

ToArtificial lungs:Resting the lung

Gattinoni L 1976? Personal Communication

Artificial Lung

CONTENTION

• We can do without Mechanical Ventilation if we do not need to breath out CO2 trough the lungs

Kolobow et al Trans. Am. Soc. Artif. Intern. Organs. 1977. 23: 17

Extracorporeal Gas Exchange

• ECMO

– high blood flow ( 4-6 l/min)

• ECCO2R

– low blood flow ( 0.5 – 2.5 l/min)

The three evils of MECHANICAL VENTILATION

• VILI

• VAP

• SEDATION

ARTIFICIAL ORGANS FOR RESPIRATORY FAILURE

Ventilatory

Membrane lung

Parenchimal

Mechanical ventilation

NEJM 2002:346: 1281

ARDS Pathophysiology

• ARDS is not just an hypoxic syndrome

• ARDS is a “Hypercapnic” syndrome

– Pulmonary vascular occlusion

– High dead space

– High minute ventilation

– High PAP

Extracorporeal CO2 removal

• Reducing ventilation anywhere down to 0 according to the

proportion of VCO2 removed

• No ventilation , no VILI

Early ARDS

• ECCO2R to :

– prevent intubation

– extend NIV application

J. M. Tonnelier Intensive Care Med 2003: 29: 2077

Variable No tube To tube P tresh sens spc

PaO2/FiO2

basal111±38 105±33 .06 <102 0.6 0.66

PaO2/FiO2

1 hr195±66 168±48 0.09 <175 0.59 0.65

RR basal

35±5 36±5 0.27 >31 0.9 0.25

RR 1 hr

27±5 30±7 0.006 >29 0.63 0.67

Antonelli : Crit Care Med. 2007 Jan;35(1):18-25.

A multiple-center survey on the use in clinical practice of NIV as a first-line intervention for ARDS.

ARDS Status

• ECCO2R to :

– from 6 to 3ml/kg and lower

Hager Am J Resp Crit Care Med 2005

Association between mortalityand Pplat

The technique seems to prevent the pulmonary barotrauma and

extrapulmonary derangements caused by conventional mechanical

ventilation

PaCO2 (mmHg) Arterial pH

baseline T0 T24 T48 T72 baseline T0 T24 T48 T72

7.0

7.1

7.2

7.3

7.4

7.5

*

* * *

***

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Anesthesiology. 2009 ;111: 826

T. Bein et al : Intensive Care Med 2013

ARDS Recovering

• ECCO2R to allow :

– early spontaneous breathing

– early extubation

– early NIV or CPAP

ECMO REVISITED

The International Journal of Artificial Organs 10, 1, 1987

Extracorporeal CO2 RemovalPhysiological Side Effects

• Extracorporeal Carbon Dioxide Removal is an experimental technique

• Extracorporeal Carbon Dioxide Removal effects on outcome are not known

• Extracorporeal Carbon Dioxide Removal Physiology and Pathophysiology is only partially understood

Kolobow et al Trans. Am. Soc. Artif. Intern. Organs. 1977. 23: 17

6 4 2 0,40

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Gas Flow Membrane Lung (l/min)

VCO2 Membrane Lung %

VCO2 Natural Lung %

What influences the respiratory drive in COPD pts undergoing PECOR?

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EAdipeak

(μV)

PaCO2 (mmHg)

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1) GF 10 L/min, VCO2ML 134 mL/min2) GF 5 L/min, VCO2ML 108 mL/min3) GF 2.5 L/min, VCO2ML 83 mL/min4) GF 0 L/min, VCO2ML 0 mL/min

R² = 0.96

What influences the respiratory drive in ARDS pts undergoing ECMO?

R² = 0,1906

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Does negative intrathoracic pressure favors lung edema ?

Annals ATS aug 2013