Number and Type of Blood Products Are Negatively Associated With Outcomes After Cardiac Surgery

Background: The association between blood transfusion and adverse outcome is documented in cardiac surgery. However, the incremental significance of each unit transfused, whether red blood cell (RBC) or non-RBC, is uncertain. This study examined the relationship of patient outcomes with the type and number of blood product units transfused. Methods: Statewide data from 24 082 adult cardiac surgery patients were included. The relationship with blood transfusion was assessed for morbidity and 30-day mortality using total number of RBC and non-RBC units transfused, specific type of non-RBC units, and different combinations of transfusion (only RBC, only non-RBC, RBC + non-RBC). Multivariable logistic regressions examined these associations. Results: Median age was 66 years (30% female patients), and 51% of patients received a transfusion (31%-66% across hospitals). Risk-adjusted analyses found each blood product unit was associated with 9%, 7%, and 4% greater odds for 30-day mortality, major morbidity, and minor morbidity, respectively (all P <.001). Odds for 30-day mortality were 13% greater with each RBC unit (P <.001) and 6% greater for each non-RBC unit (P <.001). Each unit of fresh frozen plasma (P <.001) and platelets (P <.001) increased the odds for 30-day mortality, but no effect was found for cryoprecipitate (P =.725). Odds for 30-day mortality were lower for non-RBC–only (odds ratio, 0.52; P =.030) and greater for RBC + non-RBC (odds ratio, 2.98; P <.001) compared with RBC-only transfusion. Conclusions: Independent of center variability on transfusion methods, each additional unit transfused was associated with increased odds for complications, with RBC transfusion carrying greater risk compared with non-RBC. Comprehensive evidence-based clinical approaches and coordination are needed to guide each blood transfusion event after cardiac surgery.