TABLE 1.
Patient baseline characteristics
| All patients (n = 59) | First wave (n = 15) | Second wave (n = 21) | Third wave (n = 23) | p‐value | |
|---|---|---|---|---|---|
| Age (years) | 59 (53–63) | 59 (53–66) | 62 (52–66) | 56 (51–61) | 0.722 |
| Sex | |||||
| Male | 43 (73%) | 11 (73%) | 15 (71%) | 17 (74%) | >0.99 |
| Female | 16 (27%) | 4 (27%) | 6 (29%) | 6 (26%) | >0.99 |
| Body‐mass index (kg/m2) | 29.39 (27–35) | 27.44 (25–30) | 30.86 (28–39) | 30.86 (27–35) | 0.189 |
| Comorbidities | |||||
| Hypertension | 24 (41%) | 6 (40%) | 7 (33%) | 11 (48%) | 0.594 |
| Diabetes | 15 (25%) | 4 (27%) | 4 (19%) | 7 (30%) | 0.696 |
| Coronary heart disease | 7 (12%) | 3 (20%) | 3 (14%) | 1 (4%) | 0.310 |
| Hematological malignancy | 1 (2%) | 1 (7%) | 0 | 0 | 0.254 |
| Solid organ malignancy | 1 (2%) | 0 | 0 | 1 (4%) | >0.99 |
| Immunosuppressive therapy | 3 (5%) | 1 (7%) | 1 (5%) | 1 (4%) | >0.99 |
| Scores | |||||
| SOFA | 9 (7–10) | 10 (8–11) | 8 (7–10) | 8 (7–10) | 0.315 |
| RESP | 1 (0–2) | 1 (0–3) | 1 (0–2.5) | 1 (0–2) | 0.630 |
| PRESERVE | 4 (3–6) | 5 (3–6) | 4 (3–5.5) | 4 (3–6) | 0.588 |
| Pre‐ECMO patient conditions | |||||
| Days of in‐hospital treatment before ECMO | 8.7 (5.6–14.7) | 6.5 (5–11.5) | 10.7 (6.3–17.5) | 10.6 (5.6–14.7) | 0.344 |
| Days of ICU‐treatment before ECMO | 7.65 (4–13) | 5.6 (3–10.4) | 8.0 (5.5–16) | 8.7 (4.6–11.7) | 0.353 |
| Duration of mechanical ventilation before ECMO (days) | 7.8 (4–12.7) | 5.6 (3.7–10.5) | 8.0 (4.1–16) | 8.7 (5.6–11.7) | 0.553 |
| Prone positioning | 49 (83%) | 11 (73%) | 16 (76%) | 22 (96%) | 0.109 |
| Pre‐ECMO ventilation parameters | |||||
| FiO2 (%) | 1.0 (0.9–1.0) | 1.0 (0.85–1.0) | 1.0 (0.88–1.0) | 1.0 (0.95–1.0) | 0.452 |
| Positive end–expiratory pressure (mbar) | 15 (14–16) | 15 (13–18) | 15 (13.5–16) | 15 (14–16) | 0.240 |
| Peak pressure (mbar) | 34 (31–36) | 32 (30–35) | 34 (32–36.5) | 35 (31–36) | 0.772 |
| Dynamic driving pressure (mbar) | 18 (16–21) | 16 (14–19) | 20 (17–23) | 19 (16–22) | 0.281 |
| Tidal volume (ml) | 431 (346–517) | 450 (273–517) | 431 (366–484) | 419 (340–553) | 0.883 |
| Breathing rate (1/min) | 27 (22–32) | 22 (20–27) | 27 (22–32) | 30 (24–34) | 0.055 |
| Pre–ECMO arterial blood gas analysis | |||||
| pH | 7.31 (7.21–7.40) | 7.28 (7.12–7.36) | 7.32 (7.16–7.40) | 7.35 (7.26–7.41) | 0.295 |
| PaO2 (mm Hg) | 64.2 (50.9–75.4) | 69.1 (56–84.2) | 67.0 (57.8–78.8) | 54.1 (47.6–67.9) | 0.018 |
| PCO2 (mm Hg) | 60.0 (46.9–71.7) | 63.8 (42.9–80) | 61.9 (49–72.9) | 56.2 (46.9–69.6) | 0.498 |
| PaO2/FiO2 | 67.58 (51.9–84.2) | 83.78 (56–94.5) | 71.06 (58.96–89) | 56.90 (47.6–74.13) | 0.047 |
| Bicarbonate (mmol/l) | 24.1 (22.5–28.2) | 23.90 (21.8–26.1) | 24.1 (21–29.65) | 24.70 (23.5–29.3) | 0.329 |
| Lactate (mmol/l) | 1.56 (1.2–2.0) | 1.9 (1.2–2.2) | 1.5 (1.1–1.85) | 1.50 (1.4–1.9) | 0.934 |
| Medical treatment | |||||
| Hydroxychloroquin | 11 (19%) | 10 (67%) | 0 | 1 (4%) | <0.001 |
| Lopinavir–ritonavir | 6 (10%) | 6 (40%) | 0 | 0 | <0.001 |
| Tocilizumab | 9 (15%) | 3 (20%) | 0 | 6 (26%) | 0.031 |
| Remdesivir | 8 (14%) | 2 (13%) | 5 (24%) | 1 (4%) | 0.267 |
| Methylprednisolone | 46 (78%) | 2 (13%) | 21 (100%) | 23 (100%) | <0.001 |
Note: Data are median (IQR) or n (%). Continuous variables were compared using one‐way analysis of variance (ANOVA). Categorical variables were evaluated using Freeman–Halton tests.
Abbreviations: ECMO, exatrcorporeal membrane oxygenation; ICU, intensive–care unit; PRESERVE, predicting death for severe ARDS on venovenous ECMO; RESP, respiratory extracorporeal membrane oxygenation survival prediction; SOFA, sequential organ failure assessment.