Table 1.
Baseline characteristics of patients and risk of bias
| Author (Study Design) | Total No. Patients (ECLS) | Average Age (yr) | ICU Type (country) | Days pre ECLS and Type | Severity of ARDS (P/F Ratio) in ECLS Group | Severity of ARDS (P/F Ratio) in Control Group | Cause of ARF | Lung-Protective Ventilation ECMO Arm | Lung-Protective Ventilation Control Arm | Risk of Bias* |
|---|---|---|---|---|---|---|---|---|---|---|
| Zapol 1979 (RCT) | 90 (42) | 42 | N/A (US) | 9.6, VA | 50/80† | 50/80† | Pneumonia, other | No | No | Low |
| Morris 1994 (RCT) | 40 (21) | 36 | N/A (US) | N/A, ECCO2R | 63 | 64 | Pneumonia, other | No‡ | No | Low |
| Lewandowski 1997 (Obs) | 122 (49) | 32 | Surgical (Germany) | 13, VV | 67 | 86 | Pneumonia, nonpulmonary sepsis, aspiration, polytrauma, other | N/A | Yes (PP) | High |
| Mols 2000 (Obs) | 245 (62) | 40 | Medical (Germany) | 10, VV | 96 | 126 | Pneumonia, nonpulmonary sepsis, aspiration, polytrauma, transfusion | Yes (PP) | Yes (PP) | High |
| Beiderlinden 2006 (Obs) | 150 (32) | 42 | Medical (Germany) | 5, VV | 63 | 100 | Pneumonia | Yes | N/A | High |
| Roch 2010 (Obs) | 18 (6) | 52 | Medical (France) | 0.5, VV (6), VA (3) | 52 | 96 | H1N1 | Yes | Yes | High |
| Peek 2009 (RCT) | 180 (90, 68§) | 40 | Medical (UK) | 1.5, VV | 76 | 75 | Pneumonia, polytrauma, other | Yes (PP) | Yes (PP) | Low |
| Noah 2011 (Obs) | 150 (75) | 37 | Medical, surgical, cardiovascular (UK) | 4, VV | 55 | 55 | H1N1 | Yes | N/A | Low |
| Pham 2013 (Obs) | 196 (98)∥ | 41 | Medical (France) | 2, VV (107), VA (16) | 62 | 62 | H1N1 | Yes | Yes | Low |
| Bein 2013 (RCT) | 79 (40) | 49 | Medical (Germany, Austria) | 1, ECCO2R | 152 | 168 | Pneumonia, sepsis, massive transfusion, trauma | Yes (3 ml/kg) | Yes | Low |
Definition of abbreviations: ARDS = acute respiratory distress syndrome; ARF = acute respiratory failure; ECCO2R = extracorporeal CO2 removal; ECLS = extracorporeal life support; ICU = intensive care unit; Obs = observational study; N/A = not available; P/F = PaO2/FiO2; PP = only plateau pressure limits outlined; RCT = randomized controlled trial; VA = venoarterial; VV = venovenous.
*
See online supplement.
†
P/F of 50 reflects criteria for early enrolment and P/F of 80 reflects criteria for late enrolment.
‡
Low-frequency positive pressure ventilation strategy used.
§
Number of patients in ECLS group who actually received ECLS.
∥
Using GenMatch Matching cohort.