Cardiopulmonary bypass factors affecting the development of choreoathetosis in pediatric patients

Choreoathetosis (CHO) in pediatric patients following cardiopulmonary bypass (CPB) has no known etiplogy, although several causal factors have been suggested. The infrequent occurrence in any one institution and the inability to perform prospective studies have made the etiology of CHO difficult to discover. This paper discusses a retrospective analysis of eleven cases of CHO following CPB. To form a control group for matched comparison, each of the eleven CHO patients was matched with a patient who did not develop CHO. Matching parameters included: age at operation within 10%, diagnosis (cyanotic, not cyanotic), race, gender, operation, and date of operation within 12 months. Fifteen preoperative and CPB variables were evaluated to determine differences between the CHO patients and the control patients. Statistical analysis included odds ratios for matched pairs and two sample t-tests. A p value of 0.05 was chosen to assess statistical significance. Variables found to be significantly different between the study and control groups were: lowest rectal temperature, cooling and warming rates, and lowest arterial blood temperature. From these results, it is concluded that cooling to rectal temperatures less than 15°C or a cooling rate greater than 0.4°C/min is associated with the development of CHO following CPB in these patients.