Patients with severe acute respiratory distress syndrome (ARDS) show a high mortality rate of up to 60 %. In such cases, extracorporeal membrane oxygenation (ECMO) support is often required, which would necessitate anticoagulation therapy, predominantly with heparin. Some bleeding events occurred more frequently in patients during the COVID-19 pandemic who were on venovenous (V-V) ECMO, so it is necessary to investigate whether anticoagulation management should be adjusted.

We collected data on 90 patients with severe ARDS who underwent ECMO support at the University Hospital Magdeburg between 2014 and 2022. In order to estimate the role of anticoagulation therapy as a cause of bleeding, patients were divided into two groups based on their mean activated partial thromboplastin time (aPTT): one group with a mean aPTT of more than 58 s (45 patients) and another with a mean aPTT of less than 58 s (45 patients). Demographic data, data before, during ECMO support, and bleeding complications were retrospectively recorded. We compared laboratory parameters before ECMO, essential coagulation parameters on days 3, 7, 10 of ECMO support, before the bleeding event occurred, and analyzed hospital survival in both groups.

The incidence of major bleeding complications was significantly higher in the group of patients with higher aPTT (68.9 % vs 33.3 %, p < 0.001), the differences in the occurrence of hemothorax were especially significant (28.9 % vs 2.2 %, p < 0.001). We observed better hospital patients’ survival in the group with lower aPTT (40.0 % vs 68.9 %, p = 0.006). The results of the bivariate analysis indicate that the independent predictors of hospital mortality in adult patients receiving V-V ECMO support due to severe ARDS were COVID-19 (OR: 3.504; 95 % confidence interval [CI]: 1.415–8.681, p = 0.007) acute liver failure (OR: 8.0000; 95 % CI: 1.692–37.822; p = 0.009), high antithrombin level (%) (OR: 1.036; 95 % CI: 1.003–1.071, p = 0.035). A high mean aPTT level increased the risk of major bleeding (OR: 1.080; 95 % CI: 1.016–1.148, p = 0.014) without a significant increase in mortality.

Prolonged aPTT during V-V ECMO support in patients with ARDS significantly impacts the risk of major bleeding, especially hemothorax, without significant increase in hospital mortality.