Background: Hyperthermia after cerebral ischemia is associated with worse neurologic outcome. Our goals were 3-fold: (1) to describe the postoperative temperature course in infants after cardiac surgery, (2) to compare intracardiac temperature monitoring with traditional monitoring in infants, and (3) to determine variables that influence the patients' temperatures.
Methods: Longitudinal temperature data were collected for 100 infants undergoing cardiac surgery. Intra-atrial, nasopharyngeal, esophageal, rectal, and axillary temperatures were recorded in all patients.
Results: The mean age at the time of operation was 128 +/- 166 days, and the mean weight was 5.1 +/- 2.4 kg. Circulatory arrest was used for 54 patients. In the operating room, the maximum intra-atrial temperature (37.5 degrees C +/- 0.6 degrees C) was significantly greater than both the simultaneous esophageal temperature (36.9 degrees C +/- 1.9 degrees C, P = .03) and nasopharyngeal temperature (36.3 degrees C +/- 2.5 degrees C, P < .001). In the cardiac intensive care unit, intra-atrial temperature was significantly greater than both axillary and rectal temperatures. During the first 24 postoperative hours, intra-atrial temperature was greater than 38 degrees C in 48 (48%) patients, rectal temperature was greater than 38 degrees C in 36 (36%) patients, and axillary temperature was greater than 38 degrees C in 7 (7%) patients.
Conclusions: In patients less than 2 years of age undergoing cardiac surgery requiring cardiopulmonary bypass, intra-atrial temperature peaked 4 to 6 hours after leaving the operating room. Traditional methods of temperature monitoring significantly underestimate core temperature after cardiac surgery in infants. Use of intracardiac temperature monitoring might result in avoidance of cerebral hyperthermia.