Risk factors reducing blood transfusion requirements in pediatric open heart surgery after introduction of vacuum assisted circuits

OBJECTIVES: Open heart surgery without homologous blood transfusion remains difficult in children. The introduction of vacuum-assisted cardiopulmonary bypass circuits to reduce priming volume for pediatric patients has improved the percentage of transfusion-free operations. We retrospectively analyzed blood transfusion risk factors to further reduce blood transfusion requirements after vacuum-assisted circuit introduction. METHODS: From March 1995 to June 1996, 49 patients weighing between 5 and 20 kg underwent cardiac surgery with cardiopulmonary bypass at our institution, excluding hospital deaths. We retrospectively analyzed risk factors influencing blood use in 37 patients with no blood priming in cardiopulmonary bypass after introducing a vacuum-assisted system. Factors selected for univariate analysis were age, body weight, cyanosis, preoperative Hb, operation time, cardiopulmonary bypass time, aortic cross-clamping time, and intraoperative and postoperative bleeding volume. Correlation between total bleeding volume/body weight and cardiopulmonary bypass time was studied by regression analysis. RESULTS: As risk factors, univariate analysis identified cyanotic disease, longer operation time (> 210 minutes), longer cardiopulmonary bypass time (> 90 minutes), longer aortic cross-clamping time (> 45 minutes), greater intraoperative bleeding volume/body weight (> 4 ml/kg), and greater postoperative bleeding volume/body weight (> 15 ml/kg). Regression analysis showed a significant positive correlation between total bleeding volume/body weight and cardiopulmonary bypass time. CONCLUSIONS: Cyanotic disease and long bypass time are risk factors in reducing blood transfusion requirements in pediatric open heart surgery after introduction of vacuum-assisted circuits. Further efforts are needed, however, to reduce blood transfusion requirements, particularly in these children.