Changes of Lactate Levels During Cardiopulmonary Bypass in Pediatric Undergoing Cardiac Surgery: Possible Early Marker of Morbidity and Mortality

Forty consecutive pediatric patients who required cardiopulmonary bypass for repair or palliation of complex congenital heart disease will be enrolled in this study. Patients for the study were selected by convenience sampling, without randomization or control of surgical procedure, conduct of anesthesia, or CPB management.

Patients will be monitored intra-operatively using ECG, invasive and non-invasive blood pressure monitoring, pulse oximetry and capnography for determination of End Tidal Co2 ( ETCo2 ) and nasopharyngeal temperature. After induction of anesthesia and placement of an intra-arterial catheter 1 ml of arterial blood will collected into a heparinized 3 ml blood gas syringe and immediately analyzed on the arterial blood gas analyzer (GEM Premier 3000) for blood gas, hematocrit, electrolytes, calcium and glucose. Management strategy of cardio-pulmonary bypass (CPB) was standardized for all the patients. Lactate samples will drawn at specific time points within 5 time intervals: before CPB after induction, during cooling on CPB, during rewarming on CPB, immediately after CPB in the operating room, and after admission to the post-operative intensive care unit.

Differences in lactate levels related to diagnosis will examined. To examine the effect of patient diagnosis and surgical risk on serum lactate level and outcome, the investigators separated patients into surgical risk categories Risk adjustment for congenital heart surgery (RACHS-1). This classification does not include heart transplantation. Patient mortality and the prevalence of postoperative complications for each of the 3 surgical risk categories relative to the change in lactate will examined.