Factors Associated with Blood Loss and Blood Product Transfusions

In this prospective cohort study of 548 children undergoing open-heart surgery, we evaluated demographic and perioperative factors to identify variables associated with perioperative blood loss and blood product transfusions. Using multivariate analysis, younger patient age was found to be the variable most significantly associated with bleeding and transfusions. Higher preoperative hematocrit, complex surgery, lower platelet count during cardiopulmonary bypass (CPB), and longer duration of deep hypothermic circulatory arrest were also significantly associated with bleeding and transfusion. Excessive postoperative chest tube (CT) drainage was associated with intraoperative bleeding. Independently associated variables accounted for 76% of the variability in CT output measured after 2 h in intensive care. Patients were subdivided into children aged 1 yr; infants bled more intraoperatively (P < 0.005); had greater cumulative CT output at 2, 6, 12, and 24 h (P < 0.0001); and received more blood products (P < 0.0001). Factors associated with bleeding and transfusions varied with patient age. Lower body core temperature during CPB was highly associated with blood loss and transfusions in infants, whereas resternotomy, preoperative congestive heart failure, and prolonged duration of CPB were significant factors associated with bleeding and transfusions in children >1 yr old. Implications: Knowledge of the factors associated with blood loss and blood product transfusions can help to identify children at risk of excessive bleeding after open-heart surgery. (Anesth Analg 1999;89:57-64)