Table 1.
Pre-ECMO and baseline (T0) characteristics of patients
Variable | Ultra-lung-protective group | Lung-protective group | ||
---|---|---|---|---|
N | n (%)* | N | n (%)* | |
Age, years, median (IQR) | 20 | 56 (41–65) | 18 | 57 (48–61) |
Male sex, | 20 | 13 (65) | 18 | 12 (67) |
Body mass index, kg/m2, median (IQR) | 20 | 28 (25–33) | 18 | 31 (27–36) |
SAPS 2 at admission, median (IQR) | 20 | 41 (35–49) | 18 | 45 (32–56) |
SOFA score at inclusion, median (IQR) | 20 | 8 (4–11) | 18 | 8 (5–9) |
Cause of ARDS | ||||
COVID-19 | 20 | 10 (50) | 18 | 9 (50) |
Non COVID-19 CAP | 20 | 7 (35) | 18 | 5 (28) |
Aspiration | 20 | 2 (10) | 18 | 3 (17) |
Lung contusion | 20 | 1 (5) | 18 | 0 (0) |
Extra-pulmonary sepsis | 20 | 0 | 18 | 1 (5) |
Comorbidity | ||||
Ischemic cardiomyopathy | 20 | 1 (5) | 18 | 0 (0) |
Diabetes | 20 | 5 (25) | 18 | 2 (11) |
Chronic renal insufficiency | 20 | 0 (0) | 18 | 1 (5) |
Chronic respiratory disease | 20 | 3 (15) | 18 | 2 (11) |
Immunocompromised | 20 | 1 (5) | 18 | 1 (5) |
Before ECMO, median (IQR) | ||||
Duration of mechanical ventilation, days | 20 | 8 (6–12) | 18 | 4 (1–12) |
Vasopressors | 20 | 10 (50) | 18 | 8 (44) |
Renal replacement therapy | 20 | 0 (0) | 18 | 1 (5) |
Rescue therapy pre-ECMO | ||||
Any | 20 | 20 (100) | 18 | 18 (100) |
Continuous infusion of NMB | 20 | 18 (90) | 18 | 17 (94) |
Prone position | 20 | 17 (85) | 18 | 16 (89) |
Inhaled nitric oxide | 20 | 10 (50) | 18 | 10 (55) |
Almitrine infusion | 20 | 2 (10) | 18 | 2 (11) |
Respiratory mechanics at ECMO cannulation, median (IQR) | ||||
FiO2, % | 19 | 100 (100–100) | 18 | 100 (100–100) |
PEEP, cm H2O | 16 | 14 (10–15) | 15 | 14 (12–15) |
Tidal volume, mL/PBW | 15 | 5.6 (5.4–6.1) | 15 | 6.5 (5.9–6.9) |
Respiratory rate, breaths/min | 14 | 30 (27–30) | 15 | 26 (24–30) |
Minute ventilation, L/min | 14 | 11.6 (9.7–13.1) | 13 | 10.1 (9.3–12.1) |
Plateau pressure, cm H2O | 14 | 30 (28–32) | 12 | 31 (25–33) |
Peak pressure, cmH2O | 12 | 38 (37–45) | 6 | 39 (37–41) |
Driving pressure, cm H2O | 14 | 16 (14–19) | 12 | 17 (13–20) |
RS compliance, mL/cm H2O | 14 | 21 (19–29) | 12 | 24 (18–34) |
Mechanical power, J/min | 11 | 35 (25–43) | 6 | 28 (25–33) |
Ventilatory ratio | 12 | 2.6 (2.4–3.1) | 10 | 2.5 (1.93.5) |
Last blood gas values pre-ECMO, median (IQR) | ||||
pH | 14 | 7.27 (7.21–7.33) | 14 | 7.24 (7.18–7.37) |
PaO2:FiO2, mm Hg | 18 | 74 (55–106) | 17 | 83 (72–94) |
PaCO2, mm Hg | 11 | 68 (55–72) | 11 | 59 (50–71) |
Lactates, mmol/L | 14 | 1.8 (1.0–2.5) | 13 | 1.5 (1.1–2.0) |
ECMO configuration | ||||
Femoral–jugular | 20 | 14 (70) | 18 | 16 (89) |
Femoral–femoral | 20 | 6 (30) | 18 | 2 (11) |
Respiratory mechanics and ventilator settings at baseline (T0) | ||||
FiO2, % | 16 | 100 (77–100) | 17 | 100 (50–100) |
PEEP, cm H2O | 18 | 13 (12–15) | 16 | 14 (12–15) |
Tidal volume, mL/PBW | 18 | 2.6 (1.9–3.8) | 18 | 3.5 (2.8–4.2) |
Respiratory rate, breaths/min | 18 | 13 (10–15) | 18 | 15 (11–21) |
Minute ventilation, L/min | 17 | 2.2 (1.4–3.0) | 15 | 3.1 (2.2–6.1) |
Plateau pressure, cm H2O | 16 | 24 (21–25) | 15 | 25 (24–27) |
Peak airway pressure, cmH2O | 14 | 28 (24–30) | 14 | 29 (24–36) |
Driving pressure, cm H2O | 18 | 10 (7–15) | 14 | 11 (9–15) |
RS compliance, mL/cm H2O | 18 | 17 (14–21) | 14 | 21 (13–35) |
Mechanical power, J/min | 13 | 2.7 (1.7–3.9) | 12 | 3.9 (2.9–5.6) |
ECMO settings | ||||
ECMO blood flow L/min | 18 | 4 (3.7–5.0) | 18 | 4.6 (3.9–5.2) |
Sweep gas flow, L/min | 18 | 4 (3–5) | 18 | 3.5 (3–5) |
Membrane FmO2, % | 20 | 100 (100–100) | 18 | 100 (100–100) |
Arterial blood gas | ||||
pH | 17 | 7.40 (7.36–7.44) | 18 | 7.40 (7.34–7.45) |
PaO2, mmHg | 17 | 82 (69–115) | 18 | 97 (73–118) |
PaCO2, mmHg | 17 | 49 (40–56) | 18 | 43 (37–51) |
Plasma bicarbonate, mmol/L | 17 | 30 (25–33) | 18 | 27 (22–31) |
SaO2, % | 17 | 98 (96–99) | 18 | 99 (97–99) |
Lactates, mmol/L | 16 | 1.7 (1.2–3.2) | 18 | 1.5 (1.0–3.1) |
IQR interquartile range, SAPS 2 simplified acute physiology score, SOFA sequential organ failure assessment score, ARDS acute respiratory distress syndrome, COVID-19 coronavirus disease 2019, CAP community acquired pneumonia, ECMO extracorporeal membrane oxygenation, NMB neuromuscular blockers, PEEP positive end-expiratory pressure, PBW predicted body weight, RS respiratory system, PaO2:FiO2 the ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen, PaO2 partial pressure of arterial oxygen, PaCO2 partial pressure of arterial carbon dioxide, FmO2 fraction of membrane oxygen
Driving pressure was defined as plateau pressure minus positive end-expiratory pressure. Static compliance was defined as tidal volume divided by driving pressure. Mechanical power (MP) was calculated as follows: MP = 0.098 × tidal volume x respiratory rate x (peak airway pressure − ½ × driving pressure). Ventilatory ratio was defined as [minute ventilation (ml/min) × PaCO2 (mmHg)] / (predicted body weight × 100 × 37.5). *Unless otherwise indicated