Prevention of cerebral hyperthermia during cardiac surgery by limiting on-bypass rewarming in combination with post-bypass body surface warming: A feasibility study

Cerebral hyperthermia is common during the rewarming phase of cardiopulmonary bypass (CPB) and is implicated in CPB-associated neurocognitive dysfunction. Limiting rewarming may prevent cerebral hyperthermia but risks postoperative hypothermia. In a prospective, controlled study, we tested whether using a surface-warming device could allow limited rewarming from hypothermic CPB while avoiding prolonged postoperative hypothermia (core body temperature <36degreesC). Thirteen patients undergoing primary elective coronary artery bypass grafting surgery were randomized to either a surface-rewarming group (using the Arctic Sun((R)) thermoregulatory system; n = 7) or a control standard rewarming group (n = 6). During rewarming from CPB, the control group was warmed to a nasopharyngeal temperature of 37degreesC, whereas the surface-warming group was warmed to 35degreesC, and then slowly rewarmed to 36.8degreesC over the ensuing 4 h. Cerebral temperature was measured using a jugular bulb thermistor. Nasopharyngeal temperatures were lower in the surface-rewarming group at the end of CPB but not 4 h after surgery. Peak jugular bulb temperatures during the rewarming phase were significantly lower in the surface-rewarming group (36.4degreesC +/- 1degreesC) compared with controls (37.7degreesC +/- 0.5degreesC; P = 0.024). We conclude that limiting rewarming during CPB, when used in combination with surface warming, can prevent cerebral hypothermia while minimizing the risk of postoperative hypothermia.