Effect of a standardized rewarming protocol and acetaminophen on core temperature after coronary artery bypass

Cardiac surgical patients who require hypothermic cardiopulmonary bypass experience hypothermia, normothermia, and hyperthermia during the early postoperative period. Research-based rewarming protocols are needed to manage temperature variations.

To describe the effect of a standardized rewarming protocol and acetaminophen on the following outcome variables: core temperature, peak core temperature, rewarming time, and hyperthermia.

Patients (N = 60) were rewarmed using a standardized rewarming protocol. Electric heating blankets were used for subjects with core temperatures less than 36 degrees C on admission to the intensive care unit; other subjects were covered with cotton bath blankets. Subjects were also assigned to one of three acetaminophen groups (650 mg at 38.1 degrees C, 650 mg at 37 degrees C, 1300 mg at 37 degrees C).

Using the protocol, subjects warmed to normothermia in 3.6 to 6 hours. The 16-hour core temperature thermal curves of heating blanket versus cotton bath blanket subjects differed significantly; thermal curves of the acetaminophen groups were similar. Peak core temperature was significantly lower in heating blanket subjects and unaffected by acetaminophen group. The onset of hyperthermia was not significantly affected by the method of rewarming (electric heating blanket versus cotton blankets) or acetaminophen group. Rewarming time was significantly longer for electric heating blanket subjects.

Our results indicate that mildly hypothermic subjects rewarmed with electric heating blankets during the early postoperative period have lower peak core temperatures and longer rewarming times than those rewarmed with cotton bath blankets. Acetaminophen administration at normothermia does not significantly affect peak core temperature or the onset of hyperthermia.