The Relationship Between Transfusion in Cardiac Surgery Patients and Adverse Outcomes

Objectives To understand if RBC transfusions are independently associated with a risk of mortality, prolonged intubation, or infectious, cardiac, or renal morbid outcomes. Design Retrospective review. Setting Single-institution, university hospital. Participants 2458 Patients undergoing CABG and/or valvular surgery from July 2014 through January 2018. Interventions No interventions were done. Measurements and Main Results Our primary outcome was the occurrence of the adverse event, prolonged intubation. Infectious, cardiac, and renal composite outcomes were also defined. These composites, along with mortality, were individually analyzed and then combined to form the “any adverse events” composite. Preoperative demographic and intraoperative parameters were analyzed as univariate risk factors for adverse outcomes. Logistic regression was used to screen variables with a p-value criterion of p < 0.05 for entry into the model selection procedure. Backward selection algorithm was used with variable entry and retention criteria of p < 0.05 to select the final multivariable model. Multivariable logistic regression models were used to determine whether there was an association between volume of RBC transfusion and the defined adverse event after adjusting for covariates. A p-value<0.01 was considered statistically significant in the final model of each aim to adjust for multiple comparison. The final logistic models for each of the following outcomes indicates increased risk of that outcome per each additional unit of RBC transfused. For prolonged intubation the OR=1.493, p<0.0001, for the infectious composite outcome, the OR= 1.358, p<0.0001, for adverse renal outcomes, the OR=1.247, p<0.0001, and for any adverse event, the OR=1.467, p<0.0001. Conclusions We demonstrate a strong independent association between RBC transfusion volume and adverse outcomes after cardiac surgery. Efforts should be undertaken such as preoperative anemia management and control of coagulopathy in order to minimize the need for RBC transfusion.