Table 2.
Case volume-dependent characteristics in study cohort
| Low (< 20) n/(%) | Intermediate (20–49) n/(%) | High (≥ 50) n/(%) | p | |
|---|---|---|---|---|
| Total | 96 (14.3) | 329 (48.9) | 248 (36.9) | |
| Survivor | 19 (19.8) | 97 (29.5) | 95 (38.3) | 0.0024 |
| EOLIA criteria fulfilled | 27 (28.1) | 146 (44.4) | 111 (44.8) | 0.0106 |
| SOFA (day 1) | ||||
| 0–9 | 32 (33.3) | 31 (9.4) | 64 (25.8) | 0.0005 |
| 9–12 | 20 (20.8) | 91 (27.7) | 21 (8.5) | |
| 12–15 | 15 (15.6) | 71 (21.5) | 4 (1.6) | |
| 15–21 | 10 (10.4) | 75 (22.8) | 1 (0.4) | |
| Missing | 19 (19.8) | 61 (18.5) | 158 (64.7) | |
| Intubation prior to ECMO [days] | ||||
| < 5 | 25 (26.0) | 171 (52.0) | 79 (32.9) | 0.0005 |
| 5–7 | 21 (21.9) | 51 (15.5) | 30 (12.1) | |
| ≥ 8 | 46 (47.9) | 87 (26.4) | 46 (18.5) | |
| No prior | 1 (1.0) | 9 (2.7) | 65 (26.2) | |
| Missing | 3 (3.1) | 11 (3.3) | 28 (11.3) | |
| Major bleeding or thromboembolic events | 70 (72.9) | 254 (77.2) | 112 (45.2) | < 0.0001 |
| Secondary bacterial infection (respiratory tract or bloodstream) | 69 (71.9) | 253 (76.9) | 112 (45.2) | < 0.0001 |
| Renal replacement therapy | 64 (66.7) | 208 (63.2) | 119 (48.0) | 0.0002 |
Survival, disease severity according to SOFA score, time between intubation and ECMO cannulation, incidence of complications (Major bleeding or thromboembolic events, secondary bacterial infection, renal replacement therapy) dependent on annual case volume. Results for SOFA score are given within ranges (0–9, 9–12, 12–15, 15–21). Descriptive statistics are expressed as frequencies for categorical variables (including a category for missing data). Differences between groups were tested using the Mann–Whitney U test (continuous variables), χ2 test (categorical variables) or Fisher’s exact test (categorical variables with observed frequencies < 5), as appropriate