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……..
Artificial Lung
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
NEJM 2000; 342:1301
SPECIFIC
HYPERVENTILATION
FRC
VE
(L/min)
RATIO
NORMAL
2500
<7
< 2.8
ARDS
1000
> 15
> 15
100
VA (control)
VA (actual)
X 100
MECH. VENTILATION
THEORETICAL
SPONT. VENTILATION
50
0
50
VCO2 (CDML)
VCO2 (Total)
100
X 100
Extracorporeal CO2 removal
• Reducing ventilation anywhere
down to 0 according to the
proportion of VCO2 removed
• No ventilation , no VILI
OXYGENATION
FiO2 =1.0 250 mL min-1
7000 mL min-1
PBF
Hb 15 g
Satv 82%
PvO2 47 mmHg
CO2 cont 52 mL
PvCO2 43 mmHg
Sata 98%
PaO2 110 mmHg
VO2
250
mL min-1
CO2 REMOVAL
VA 9500 mL min-1
1100 mL min-1
PBF
CO2 cont 34 mL
PaCO2 15 mmHg
VCO2
200
mL min-1
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 cmH2O
43 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 study
Conrad 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
7.5
90
*
80
70
7.4
*
*
*
60
*
7.3
*
*
7.2
50
7.1
40
7.0
30
baseline T0 T24 T48 T72
baseline T0
Anesthesiology. 2009 ;111: 826
T24 T48 T72
*
TIME TO HEAL
Arteriovenous extracorporeal respiratory support
Implementation
Vv ILA with a pump
The A Lung
PALP System
Extracorporeal CO2 Removal
Physiological 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?
35
EAdi peak (μV)
30
4
25
R² = 0.9107
20
3
15
2
1
10
1)
2)
3)
4)
5
0
7.3
GF 10 L/min, VCO2ML 134 mL/min
GF 5 L/min, VCO2ML 108 mL/min
GF 2.5 L/min, VCO2ML 83 mL/min
GF 0 L/min, VCO2ML 0 mL/min
7.32
7.34
7.36
Arterial pH
7.38
7.4
7.42
What influences the respiratory drive
in COPD pts undergoing PECOR?
35
1)
2)
3)
4)
EAdi peak (μV)
30
25
GF 10 L/min, VCO2ML 134 mL/min
GF 5 L/min, VCO2ML 108 mL/min
GF 2.5 L/min, VCO2ML 83 mL/min
GF 0 L/min, VCO2ML 0 mL/min
20
4
3
2
15
1
10
R² = 0.96
5
0
40
45
50
55
PaCO2 (mmHg)
60
65
100
80
60
40
VCO2 Natural Lung %
20
VCO2 Membrane Lung %
0
6
4
2
0,4
Gas Flow Membrane Lung (l/min)
What influences the respiratory drive
in ARDS pts undergoing ECMO?
25
R² = 0.1906
EAdi peak (μV)
20
15
10
5
0
30.0
35.0
40.0
45.0
PaCO2 (mmHg)
50.0
55.0
Extracorporeal CO2 Removal
Physiological Side Effects
• Decreased PA O2: ( Due to decreased QR)
• Decreased TV - Decrecruitment
– Higher PEEP Maintain Paw
• Ineffective Coughing ( ?)
PAO2= FiO2 *713 - ( PaCO2/R)
FiO2
1
PACO2 = 35 mmHg
PAO2 300 mmHg
0.5
PAO2 200 mmHg
PAO2 100 mmHg
AIR
0
0
0.5
1
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
200
Δ 69%
180
160
VCO2 (ml/min)
Δ 27%
140
Δ18%
120
100
80
60
VCO2 standard conditions
40
VCO2
ALCOR
20
0
0
1
2
3
4
Acid infusion (mmol/min)
5
6
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 Assist
3 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