Oxygenation management during veno-arterial ECMO support for cardiogenic shock: a multicentric retrospective cohort study.

BACKGOUND: Hyperoxemia is common and associated with poor outcome during veno-arterial extracorporeal membrane oxygenation (VA ECMO) support for cardiogenic shock. However, little is known about practical daily management of oxygenation. Then, we aim to describe sweep gas oxygen fraction (FS O2 ), postoxygenator oxygen partial pressure (PPOST O2 ), inspired oxygen fraction (FI O2 ), and right radial arterial oxygen partial pressure (Pa O2 ) between day 1 and day 7 of peripheral VA ECMO support. We also aim to evaluate the association between oxygenation parameters and outcome. In this retrospective multicentric study, each participating center had to report data on the last 10 eligible patients for whom the ICU stay was terminated. Patients with extracorporeal cardiopulmonary resuscitation were excluded. Primary endpoint was individual mean FS O2 during the seven first days of ECMO support (FS O2  mean (day 1-7) ).

RESULTS: Between August 2019 and March 2022, 139 patients were enrolled in 14 ECMO centers in France, and one in Switzerland. Among them, the median value for FS O2  mean (day 1-7) was 70 [57; 79] % but varied according to center case volume. Compared to high volume centers, centers with less than 30 VA-ECMO runs per year were more likely to maintain FS O2 ≥ 70% (OR 5.04, CI 95% [1.39; 20.4], p = 0.017). Median value for right radial Pa O2  mean (day 1-7) was 114 [92; 145] mmHg, and decreased from 125 [86; 207] mmHg at day 1, to 97 [81; 133] mmHg at day 3 (p < 0.01). Severe hyperoxemia (i.e. right radial Pa O2 ≥ 300 mmHg) occurred in 16 patients (12%). PPOST O2 , a surrogate of the lower body oxygenation, was measured in only 39 patients (28%) among four centers. The median value of PPOST O2  mean (day 1-7) value was 198 [169; 231] mmHg. By multivariate analysis, age (OR 1.07, CI95% [1.03-1.11], p < 0.001), FS O2  mean (day 1-3) (OR 1.03 [1.00-1.06], p = 0.039), and right radial Pa O2  mean (day 1-3) (OR 1.03, CI95% [1.00-1.02], p = 0.023) were associated with in-ICU mortality.

CONCLUSION: In a multicentric cohort of cardiogenic shock supported by VA ECMO, the median value for FS O2  mean (day 1-7) was 70 [57; 79] %. PPOST O2 monitoring was infrequent and revealed significant hyperoxemia. Higher FS O2  mean (day 1-3) and right radial Pa O2  mean (day 1-3) were independently associated with in-ICU mortality.