Extracorporeal CO2 Removal in ARDS

Antonio Pesenti

University of Milano Bicocca

Italy

HISTORY

First RCT on ECMO in ARDS.

No MV protocol during ECMO, only a generic indication of reducing inspiratory pressure and FiO2

Adult respiratory distress syndrome (ARDS): why did ECMO fail? Kolobow T, et al Int J Artif Organs. 1981 ;4:58

• We believe severely diseased lungs have a chance to heal only if the environment remains conducive to the healing of the lung.

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

From Oxygenators: Buying time with artificial lungs

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

To Artificial lungs:Resting the lung

Gattinoni L 1976? Personal Communication

Artificial Lung

NEJM 2000; 342:1301

FRCVE

(L/min) RATIO

NORMAL

ARDS

2500 < 7 < 2.8

1000 > 15 > 15

SPECIFIC HYPERVENTILATION

MECH. VENTILATION THEORETICAL SPONT. VENTILATION

VCO2 (CDML)

VCO2 (Total)

X 100

500 100

50

100

VA (

actu

al)

VA (

con

tro

l)X

100

Extracorporeal CO2 removal

• Reducing ventilation anywhere down to 0 according to the

proportion of VCO2 removed

• No ventilation , no VILI

OXYGENATIONFiO2 =1.0 250 mL min-1

CO2 REMOVALVA 9500 mL min-1

VO2 250

mL min-1

VCO2 200

mL min-1

Sata 98%

PaO2 110 mmHg

CO2 cont 34 mL

PaCO2 15 mmHg

Hb 15 gSatv 82%PvO2 47 mmHgCO2 cont 52 mLPvCO2 43 mmHg

7000 mL min-1

PBF

1100 mL min-1

PBF

Gattinoni et al., International Anesthesiology Clinics, 1983; 21: 97-117

The technique seems to prevent the pulmonary barotrauma and

extrapulmonary derangements caused by conventional mechanical

ventilation

LFPPV ECCO2R IN SEVERE ACUTE

RESPIRATORY FAILURE GATTINONI et al: JAMA 1986

ECMO CRITERIA + TSLC < 30 cmH2O43 patients 21 survivors (49%)

Mean by-pass length: Survivors 5.4 ± 3.5 days NonSurvivors 10.6 ± 6.6 days

Bleeding: 1800 ± 500 ml/day

Pumpless extracorporeal lung assist and

adult respiratory distress syndrome

Reng M et al., The Lancet 2000; 356 (15)

Total extracorporeal arteriovenous carbon dioxide removal in ARF: a phase I clinical

studyConrad S et al. ICM 2001; 27: 1340

8 patients

72 hr AVCO2R

PaCO2 VE

FROM

90.8 ± 7.5

6.92 ± 1.6

TO 51.8 ± 3.1

3.0 ± 0.53

Critical Care 2006, 10:R151

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

*

* * *

***

*

30

40

50

60

70

80

90

Anesthesiology. 2009 ;111: 826

TIME TO HEAL

ImplementationArteriovenous extracorporeal respiratory support

Vv ILA with a pump

The A Lung

PALP System

Extracorporeal CO2 RemovalPhysiological Side Effects

• Decreased PA O2: ( Due to decreased QR)

• Decreased TV - Decrecruitment – Higher PEEP equal Paw

• Ineffective Coughing ( ?)

Marcolin R et al Trans Am Soc Artif Intern Organs 1986

Marcolin R et al Trans Am Soc Artif Intern Organs 1986

Marcolin R et al:Trans Am Soc Artif Intern Organs 1986

What influences the respiratory drive in COPD pts undergoing PECOR?

7.31 7.32 7.33 7.34 7.35 7.36 7.37 7.38 7.39 7.4 7.41 7.420

5

10

15

20

25

30

35

R² = 0.910674964692639

Arterial pH

EAdi

pea

k (μ

V)

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

4

3

21

What influences the respiratory drive in COPD pts undergoing PECOR?

40 45 50 55 60 650

5

10

15

20

25

30

35

PaCO2 (mmHg)

EAdi

pea

k (μ

V)

4

3

21

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

6 4 2 0,40

20

40

60

80

100

Gas Flow Membrane Lung (l/min)

VCO2 Membrane Lung %

VCO2 Natural Lung %

What influences the respiratory drive in ARDS pts undergoing ECMO?

30 35 40 45 50 550

2

4

6

8

10

12

14

16

R² = 0.190569006130476

PaCO2 (mmHg)

EAdi

pea

k (μ

V)

Extracorporeal CO2 RemovalPhysiological Side Effects

• Decreased PA O2: ( Due to decreased QR)• Decreased TV - Decrecruitment

– Higher PEEP Maintain Paw• Ineffective Coughing ( ?)

AIR

0.5

0

1

0 0.5 1

PAO2 100 mmHg

PAO2 200 mmHg

PAO2 300 mmHg

PACO2 = 35 mmHg

FiO2

R

PAO2= FiO2 *713 - ( PaCO2/R)

Cereda M et al. Chest 1996; 109: 480

FUTURE

VILI PREVENTION: THE IDEAL TOOL

• Peripheral low flow cannulation• 250-500 ml/ min blood flow• 50-80 % total CO2 production• Regional anticoagulation• Simple Safe circuitry ( CVVH)

Zanella A et al

Total CO2 elimination by a membrane lung

0

20

40

60

80

100

120

140

160

180

200

0 1 2 3 4 5 6

Acid infusion (mmol/min)

VC

O2

(ml/

min

)

VCO2 standard conditions

VCO2 ALCOR

Δ18%

Δ 69%

Δ 27%

ECLA: different techniques for different goals

1. Rescue of most severe hypoxemia– ARDS

2. Hyper protective ventilation– ARDS

3. Alternative to invasive ventilation– ARDS, COPD

Extracorporeal lung Assist3 ALTERNATIVE TO VENTILATION

1. BLOOD FLOW UNDEFINED

2. SOUND PATHOPHYSIOLOGY

The three evils of MECHANICAL VENTILATION

•VILI•VAP•SEDATION

Extracorporeal support rationale

“... the best therapeutic strategy, to reduce the risk of new pneumothoraces and to stop the air leak, would be to dispense with mechanical ventilation or any form of

positive airway pressure. Spontaneous breathing could be maintained by supplementing the spontaneous CO2 clearance with partial extracorporeal CO2 removal.”

Pesenti A., et al: Percutaneous Extracorporeal CO2 Removal in a Patient with Bullous Emphysema with Recurrent Bilateral Pneumothoraces and

Respiratory Failure. Anesthesiology 1990; 72: 571-573