There is increasing awareness that erythrocyte transfusions after pediatric cardiac surgery have deleterious effects. Despite reports of decreased transfusion requirements associated with smaller cardiopulmonary bypass circuits, the relationship between circuit prime volume and need for transfusion has not been systematically examined.
Pediatric patients at our institution who underwent cardiopulmonary bypass between January 2005 and December 2010 were reviewed. Demographics, intraoperative data, and transfusion of packed red blood cells were retrospectively recorded. Cardiopulmonary bypass prime volume was indexed by patient body surface area. Logistic regression analysis was used to correlate these variables with need for transfusion.
In the perioperative period, 1912 patients received transfusions and 266 did not. In univariate analysis, indexed prime volume was a significant predictor of transfusion (odds ratio, 1.007; P < .001). Other significant variables in univariate analysis included age, surgeon, Risk Adjustment for Congenital Heart Surgery 1 (RACHS-1) category, preoperative hemoglobin, total bypass time, aortic crossclamp time, use and duration of deep hypothermic circulatory arrest, lowest body core temperature, and cardiopulmonary bypass flow rate. Previous cardiac surgery was not a significant predictor. In multivariable analysis controlling for RACHS-1 category, surgeon, minimal core body temperature, and preoperative hemoglobin, indexed prime volume remained an independent predictor of transfusion (odds ratio, 1.006; 95% confidence interval, 1.005-1.007, P < .001).
Perioperative need for transfusion in pediatric cardiac surgical patients is independently related to the prime volume of the cardiopulmonary bypass circuit. It therefore seems prudent to minimize circuit prime volumes to avoid unnecessary use of blood products.