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. 2021 Nov 15;11:157. doi: 10.1186/s13613-021-00943-0

Table 4.

Comparison of patient’s characteristics according to their obese status in univariate analysis

Non-obese patients (n = 44) Obese patients (n = 29) p value
Demographic characteristics
 Age (years) 60.5 (56–64.5) 61 (54–64) 0.78
 Sex (male) 35 (79.5%) 21 (72.4%) 0.48
 BMI (kg/m2) 26.45 (25.35–27.8) 33.5 (31–35.8) < 0.001
First wave, n (%) 16 (36) 7(24) 0.27
Severity scores
 SAPS II 30 (25.5–36) 29 (25.5–34.5) 0.60
 SOFA 3 (2–4) 3 (2–4) 0.95
Charlson score 2 (2–3) 2 (1–3) 0.58
ICU therapy before ECMO
 High-flow nasal O2, n (%) 38 (86) 26 (90) 0.68
  Duration (days) 5 (1–7) 2 (1–6) 0.08
 Non-invasive ventilation, n (%) 18 (41) 17 (59) 0.14
  Duration (days) 4 (0–6) 1 (0.5–3) 0.15
 Prone positioning, n (%) 44 (100) 28 (97) 0.21
  Number of sessions 2 (1–5) 2 (1.5–4) 0.88
 Dexamethasonea, n (%) 28 (65) 19 (65.5) 0.97
Time from first symptoms to intubation, days 11 (7.5–15) 10 (7–13) 0.1
Time from hospitalization to intubation, days 5.5 (1–9) 4 (1–6) 0.06
Time from ICU admission to intubation, days 4 (1–7) 2 (0–4) 0.048
Predictive survival scores under ECMO
 RESP score 1 (0–2) 1 (1–4) 0.09
 ECMO net score 5.5 (4–6) 4.5 (4–6) 0.73
 PRESERVE score 4 (3–5) 2 (1–3) < 0.001
 SOFA before ECMO 8 (4–9) 5 (4–8) 0.58
MV duration before ECMO, days 7 (3–10.5) 5 (3–8) 0.35
Time from ICU admission to ECMO, days 11 (8–14.5) 9 (4–11) 0.02
Ventilation parameters before ECMO
 FiO2 100 100 0.58
 Plateau pressure, cmH2O 28 (25–30) 29 (25–31) 0.92
 Positive end-expiratory pressure, cmH2O 10 (8–12) 14 (10–15) < 0.001
 Driving pressure 17 (14–20) 14.5 (12–20) 0.1
 Tidal volume, mL/kg predicted bodyweight 5.7 (5–6,21) 5.85 (5.6–6.2) 0.30
 Respiratory rate, breath per minute 26 (23–30) 26.5 (20–30) 0.83
 Mechanical power, J/min 17.7 (14.07–22.22) 20.3 (17.7–29.7) 0.06
 Ventilatory ratio 2.42 (1.55–2.90) 2.34 (1.87–2.75) 0.81
 Static compliance, mL/cmH2O 23 (15.5–27.33) 26.25 (21–39.09) 0.07
Last blood-gas values before ECMO
 PaO2/FiO2 ratio 71.5 (64–84) 75 (62–81) 0.93
 pH 7.35 (7.26–7.38) 7.31 (7.26–7.39) 0.49
 PaCO2, mmHg 57.5 (50.5–65.5) 60 (52–66) 0.99

73 patients were included in this analysis, 3 patients were excluded because of missing data for BMI

Data are expressed as median (interquartiles) or number (percentage, %)

Obesity was defined by a BMI superior or equal to 30 g/m2

Mechanical power (MP) was calculated as follows: MP = 0.098 × tidal volume × respiratory rate × (peak pressure − ½ × driving pressure). Driving pressure was defined as plateau pressure minus positive end-expiratory pressure. Static compliance was defined as tidal volume divided by driving pressure

BMI: body mass index; NSAID: non-steroidal anti-inflammatory drug; ACE: angiotensin converting enzyme; ARB: angiotensin II receptor blockers; SAPS II: Simplified Acute Physiology score; SOFA: Sequential Organ Function; ICU: intensive care unit; ECMO: extra-corporeal membrane oxygenation; MV: mechanical ventilation; O2: oxygen; PaO2: partial pressure of arterial oxygen; FiO2: fraction of Inspired oxygen; PaCO2: partial pressure of arterial carbon dioxide; PaO2/FiO2: ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen; RESP score [17]: Respiratory Extracorporeal Membrane Oxygenation Survival Prediction Score; ECMO net score [18]: score from the Italian ECMO network; PRESERVE score [19]: PRedicting dEath for SEvere ARDS on VV-ECMO score

aPatients receiving dexamethasone 6 mg per day or equivalent dose of corticosteroids