A clinical audit of blood product utilization for coronary artery bypass surgery in the Western Cape

Abstract

Background: Numerous international studies have documented variation in transfusion practice for Coronary Artery Bypass (CABG) surgery, despite the widespread availability of clinical guidelines. Optimally, blood management systems seek to streamline utilization with key indicators being patient care and outcome as well as potential waste and cost of blood. To facilitate this view this study sought to audit blood product utilization for Coronary Artery Bypass Graft (CABG) surgery. Methods: Blood utilization at both a public and a private hospital in the Western Cape underwent an observational retrospective audit. Participating hospitals completed a data form for fifty consecutive patients undergoing isolated, elective CABG surgery. Information obtained included age, gender, weight, co-morbidities, pre and post-operative international normalized ratio (INR), haemoglobin (Hb), platelet count, serum creatinine, operative details, use of anticoagulants as well as transfusion history. Data was then analysed with the IBM SPSS version 22 statistical package. Results: The transfusion rate at the private hospital (56%) was significantly lower than at the public hospital (92%) (p<0.001) and these results were carried through to mean number of red cell concentrates transfused (1.9 vs. 3.3; p<0.001). Despite similar pre-operative haemoglobin (Hb) counts at both hospitals, post-operative Hb was considerably higher at the public hospital (p<0.001). The majority of patients at both hospitals were male whose transfusion rates were significantly lower than females (69.8% vs. 100%; p<0.001) as was their RCC utilisation (3.6 vs. 2.4; p<0.005). Moreover significant differences where noted in the transfusion rates between males at the two hospitals (50% vs. 90%; p<0.001). Furthermore, a significant difference was observable between the ages of transfused and non-transfused patients at both hospitals with the private hospital having significantly older patients (p<0.05) whilst decreased weight was also shown to be a significant factor (p<0.001) in predicting transfusion. It was notable that patients at the public hospital where significantly lighter than patients at the private hospital (p<0.001). The presentation of ischaemia sufferers was also significantly higher at the private hospital (p<0.001) who in addition performed greater quantities of grafts (p<0.001) and had greater quantities of pre-operative aspirin usage (p<0.05). Conclusion: Despite its small size, this study was able to demonstrate that the private sector hospital had a significantly lower transfusion rate than the public sector hospital despite having increased numbers of grafts, older patients with higher levels of ischaemia. In conclusion, the higher transfusion rate demonstrable at the public hospital was probably due to a more liberal transfusion policy. With the inclusion of data from additional studies comparing public and private health care institutions for cardiac surgery, the hope is that protocols detailing patient blood management (PBM) may be developed.