Restrictive Versus Liberal Transfusion Strategy in Extracorporeal Membrane Oxygenation

Abstract Background: To compare the clinical outcomes of patients requiring extracorporeal membrane oxygenation (ECMO) support who had a restrictive red cell transfusion strategy with those who had a liberal transfusion strategy. Methods: We retrospectively reviewed all adult ECMO cases in Hong Kong from 2010 to 2019. Patients who received a minimum of one packed red blood cell (pRBC) during ECMO were included. Haemoglobin values before each episode of transfusion was retrieved. Restrictive transfusion strategy was defined as a transfusion threshold ≤ 8.5 g/dL in all transfusion episodes for a single patient, while liberal transfusion strategy was defined as a transfusion threshold > 8.5 g/dL in any transfusion episode. Mortality outcomes and other complications were compared.Results: The analysis included 763 patients, with 138 (18.1%) patients in the restrictive and 625 (81.9%) in the liberal transfusion strategy group, and median haemoglobin of 8.3 and 9.9 g/dL, respectively. The average units of pRBC received per day were 0.7 (0.3-1.8) and 1.2 (0.6-2.3) in the two groups. There were no significant differences in ICU mortality (adjusted odds ratio (OR), 0.86; 95% CI 0.56-1.30; P=0.47), hospital mortality (adjusted OR, 0.79; 95% CI 0.52 to 1.21; P=0.28), and 90-day mortality (adjusted OR, 0.84; 95% CI 0.55 to 1.28; P=0.42) between the two groups. Among patients receiving veno-venous ECMO, the ICU mortality was significantly lower with the restrictive transfusion strategy (adjusted OR, 0.36; 95% CI 0.17 - 0.73; P=0.005). Conclusions: Compared with a liberal transfusion strategy, a restrictive red blood cell transfusion threshold of 8.5 g/dL was not associated with worse outcomes in patients on ECMO, with better survival outcomes for patients on veno-venous ECMO.