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. 2022 Dec 12;26:383. doi: 10.1186/s13054-022-04272-x

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