Blood transfusion related to procedure in adult patients undergoing cardiac surgery

Abstract

Introduction: Blood transfusions are associated with increased adverse outcomes and healthcare costs. While the aim of transfusion is to improve patient outcomes by enhancing tissue oxygenation, this must be weighed against the risks of transfusion-associated complications. Patient blood management programmes (PBM) have been implemented in many developed countries and have shown decreased blood utilisation and improved outcomes. Cardiac surgery is a significant consumer of blood supplies, despite evidence demonstrating the safety of restrictive transfusion strategies. This study aimed to determine the risk of blood transfusion, according to type of surgical procedure, in cardiac surgical patients in a quaternary level referral hospital in South Africa.
Methods: This single centre, prospective observational study conducted over 18 weeks at Inkosi Albert Luthuli Central Hospital investigated the risk of packed red blood cell (PRBC) transfusion from the intraoperative period until discharge in adult patients undergoing elective CABG (n = 30), valve surgery (n = 53) or redo surgery (n = 11) under cardiopulmonary bypass. Poisson regression assessed the effect of type of procedure, age, gender, body mass index, preoperative haemoglobin and EuroSCORE II as risk factors for PRBC transfusion.
Results: Ninety-four patients were recruited. There was no statistically significant association between risk of PRBC transfusion in valve surgery (IRR 0.71; 95% CI 0.51–1; p = 0.052) and redo surgery (IRR 0.87; CI 0.49–1.52; p = 0.621) when compared to CABG. Increased risk of PRBC transfusion was associated with female gender (IRR 1.72; 95% CI 1.24–2.41; p = 0.001) and EuroSCORE II (IRR 1.06; 95% CI 1.02–1.1; p = 0.001). Increasing preoperative haemoglobin levels were associated with a lower risk of PRBC transfusion (IRR 0.89; 95% CI 0.82–0.98; p = 0.013). Median number of PRBC units transfused was: 2 units (entire cohort); 3 units (CABG); 2 units (valve surgery); and 3 units (redo surgery).
Conclusions: PRBC transfusion occurred in 80% of patients undergoing cardiac surgery, however the risk of blood transfusion was not associated with the type of surgical procedure. Implementation of a PBM protocol may decrease the incidence of preoperative anaemia, which was present in half the study population.