M. Cerullo2, F. Gani2, S. Y. Chen2, J. K. Canner2, W. W. Yang3, S. M. Frank3, T. M. Pawlik1 1Ohio State University,Wexner Medical Center,Columbus, OH, USA 2Johns Hopkins University School Of Medicine,Department Of Surgery,Baltimore, MD, USA 3Johns Hopkins University School Of Medicine,Department Of Anesthesiology And Critical Care Medicine,Baltimore, MD, USA
Introduction: Current guidelines for transfusion largely focus on nadir hemoglobin (Hb) levels. Hb triggers may not be helpful, however, in defining appropriate intra-operative use of packed red blood cells (PRBCs). We sought to define the use intra-operative PRBC relative to quantitative physiologic factors at the time of surgery.
Methods: Prospective perioperative data on patients undergoing major gastrointestinal surgery between 2010 and 2014 were analyzed. Risk of intraoperative transfusion was assessed with multivariable extended Cox models using clinical covariates (e.g. type of surgery, perioperative Hb, coagulation parameters, American Society of Anesthesiologists (ASA) classification, and Charlson co-morbidity), as well as time-varying intraoperative covariates (e.g. continuously-monitored mean arterial pressure [MAP], heart rate, and estimated blood loss [EBL]).
Results: 2,428 patients were identified; 384 (15.8%) patients received an intraoperative transfusion. Higher risk of intraoperative transfusion was associated with preoperative factors including lower Hb (hazard ratio [HR]=1.22, 95% confidence interval [CI]: 1.14-1.30, p<0.001) and higher ASA class (HR=1.55, 95%CI:1.24-1.93, p<0.001). Intraoperative risk factors for transfusion included higher EBL (HR=1.43, 95%CI:1.27-1.62, p<0.001, per 1000mL), as well as lower instantaneous MAP (HR=1.15, 95%CI:1.08-1.22, p<0.001) and higher heart rate (HR=1.30, 95%CI:1.21-1.39, p<0.001). While the majority of patients had a transfusion for a physiologic indication, among the 384 patients transfused, 27.1% of intra-operative transfusions were delivered to patients who never had a physiologic indication (heart rate>100, MAP<65, or a nadir Hb<8) (Figure).
Conclusion: Physiologic indicators account for considerable variability in intraoperative transfusion practices among patients undergoing major surgery. Up to 27% of patients who received an intraoperative transfusion had no identifiable physiological reason for a transfusion, thereby suggesting possible overutilization of PRBC in a subset of patients.
