Does cardiopulmonary bypass temperature correlate with postoperative central nervous system dysfunction?

A National Institutes of Health-funded trial of perfusate temperature and neurological function was begun in the Baystate Medical Center in February 1994. It randomizes patients having coronary revascularization to three temperatures--warm (37 degrees C), tepid (32 degrees C), and cold (20 degrees C)--for systemic perfusate and blood cardioplegia temperature at 37 degrees C warm, 32 degrees C tepid, and 6 degrees C to 10 degrees C cold. The goal is to have a quantitated neurological examination performed prior to operation, prior to discharge at day 3 or 4, and at a 1-month follow-up interval. The initial 51 patients completing a 1-month follow-up broke down to 14 cold, 22 tepid, and 15 warm. The neurological examination quantitated their performance on the Mathew Scale, an ordinal measure from 1 to 100, with 100 being normal. There was a significant (p < 0.05) decrease across the entire study from preoperative to postoperative that was no longer present at late follow-up. Although the lowest mean scores (94.8) occurred in the warm group, they were not statistically different from the other groups', and there was no discernible influence of temperature on neurological function. Additional patients will be entered to validate a difference if such exists.