Transfusion requirement prediction score for patients undergoing cardiac surgery: An experience from a tertiary care set-up from South India

Background: Prediction of transfusion requirement is part of preoperative management in a surgical case. We aimed to develop one such tool for patients undergoing cardiac surgery. Methods: A retrospective study for a period of 3 years was done to develop the scoring tool, Transfusion Requirement Prediction Score for Cardiac Surgery (TRPS), and internal validation was done prospectively. The primary outcome was administration of allogenic red cell units to the patients during perioperative period. The outcome is dichotomized as controls and cases based on the number of Red Blood Cell units received. Independent variables were chosen based on statistical significance and clinical judgement. Receiver operating characteristic curve was used to obtain the cut-off for each independent variable, odds ratio, and regression coefficients were used to assign the score. All patients with a cumulative score below the cut-off value were categorised as ‘low risk’ and above the cut off as ‘high risk’ group. Results: During the study period, out of 602 patients, 345 met the inclusion criteria (controls: 175; cases: 170). Six variables such as age (more than 58 years), gender (female), bypass time (more than 148 min), haemoglobin (less than 12.5 g/dL), ejection fraction (less than 57%), and history of warfarin prophylaxis were chosen to develop the score. The total score value of 5 was chosen as the cut-off for the two risk groups. It predicted blood utilisation with a strength of 68% sensitivity and 79% specificity. On internal validation, the score was observed to have an accuracy of 70%. Conclusion: The TRPS is a simple reliable and handy tool with high accuracy.