Impact of Point-of-care allogeneic red blood cell washing on markers of transfusion-related respiratory complications: A phase II randomized clinical trial

Background: Transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) are leading causes of transfusion-related morbidity and mortality. Soluble factors in red blood cell (RBC) supernatant may increase risk for these complications. We hypothesized that point-of-care allogeneic RBC washing may be an effective intervention to mitigate elevations in soluble factors as well as physiologic responses associated with transfusion-associated respiratory complications in the setting of cardiac surgery. Methods: This is a two-center, non-blinded, randomized clinical trial evaluating point-of-care washed versus standard-issue allogeneic RBC transfusions administered during or on the day of cardiac surgery. The primary analysis was performed via modified intention-to-treat. The primary outcomes assessed were changes in intermediate markers of lung injury as well as cardiopulmonary physiologic responses to RBC transfusion. Secondary outcomes included the duration of intensive care unit and hospital stay, durations of mechanical ventilation and oxygen supplementation, presence of TRALI or TACO, and mortality. Results: Among 154 analyzed patients (81 washed, 73 standard issue), median age was 66 years and 77 (50.0%) were women. The median (IQR) number of allogeneic RBC units transfused on the day of surgery was 3.0 (2.0 - 5.0) in the washed RBC group and 3.0 (2.0 - 4.0) in the standard issue group (p = 0.13). No between-group differences were identified in any of the assessed recipient lung injury biomarkers (all p-values > adjusted alpha). Durations of intensive care unit stay (median [interquartile range]; 3.0 [2.0-5.0] versus 3.0 [2.0-4.0] days; p = 0.117) and hospital length of stay (12.0 [9.0-17.0] versus 12.0 [9.0-17.0] days; p = 0.801) were similar, as were the number of ventilator-free days at day 28 (27.0 [27.0-27.0] versus 27.0 [26.0-27.0]; p = 0.699) and oxygen free days at day 28 (24.0 [19.0-26.0] versus 24.0 [22.0-26.0]; p = 0.400) . No significant differences were noted in mortality rate nor in incidence rates for TRALI, TACO, and acute kidney injury. Conclusions: Among patients undergoing cardiovascular surgery with high risk of RBC transfusion, point-of-care washing of allogeneic RBC transfusions did not mitigate changes in intermediate markers of lung injury or cardiopulmonary physiologic responses to RBC transfusion and was not associated with improved clinical outcomes.