Neurological outcome of normothermic versus hypothermic cardiopulmonary bypass in simple congenital heart diseases

Abstract

Objective We hypothesized that normothermic cardiopulmonary bypass (CPB) may provide equivalent results to hypothermic CPB on neurological outcome. Patients and methods Forty patients were randomized to one of two groups: group 1 that underwent normothermic CPB (>35°C) and group 2 that underwent mild hypothermic CPB (32°C). Perfusion on bypass was performed by a nonpulsatile pump flow with an average flow rate around 2.4 l/m 2 /min. A pH-stat carbon dioxide management strategy was used. The arterial and jugular venous blood gases, mean cerebral blood flow velocity (CBFV), and pulsatile index were measured as basal, after induction of anesthesia, at the onset of CPB, 20-30-40 min after the CPB, at the cessation of CPB, and at the end of the operation. Neurological outcomes were assessed by computed tomography scanning and Wechsler Preschool and Primary Scale of Intelligence preoperatively, at the third postoperative day and 1 month after surgery. Postoperative ICU variables such as duration of mechanical ventilation, time to extubation, and ICU length of stay were recorded. Results There was a significant increase in SjvO 2 and decrease in CeO 2 in the hypothermia group of patients after establishment of hypothermia by 10 and 20 min when compared with the normothermic group ( P 2 was maximal during normothermic CPB and after rewarming phase of hypothermic CPB. There were no significant changes in computed tomography scanning and Wechsler Preschool and Primary Scale of Intelligence between the studied groups at any time period. There was significant prolongation in duration of postoperative mechanical ventilation, extubation time, and duration of ICU stay in the hypothermic group of patients compared with the normothermic group ( P Conclusion During CPB for correction of congenital heart defects, the normothermic and hypothermic CPB were comparable with respect to the neurological outcome. However, normothermia permits shorter time on mechanical ventilation, more rapid extubation, and shorter ICU stay time compared with hypothermia.