COMPARISON OF BRAIN TEMPERATURE WITH BLADDER AND RECTAL TEMPERATURES IN ADULTS WITH SEVERE HEAD-INJURY

OBJECTIVE: The purpose of this study was to compare brain temperature (Tbr) with conventional indicators of core body temperature (i.e., rec tal temperature [Tre] and bladder temperature [Tbl]), in adults with s evere head injury. METHODS: The relationships between Tbr and Tbl and between Tbr and Tre are described in terms of differences in temperatu re in eight patients with severe head injury. INSTRUMENTATION: Brain t issue temperature was measured every minute, with a thermocouple embed ded 2 cm from the tip of a ventriculostomy catheter used to measure in tracranial pressure. Tbl was measured with a thermistor embedded in a bladder catheter, and Tre was measured with a thermistor in a rectal p robe. RESULTS: Tbr was usually greater than Tbl and Tre. The average d ifference between Tbr and Tbl for each patient ranged from 0.32 to 1.9 degrees C, with standard deviations of the difference ranging from 0. 30 to 0.80 degrees C. The average difference between Tbr and Tre for e ach patient ranged from 0.1 to 2.0 degrees C, with, standard deviation s of the difference ranging from 0.32 to 1.08 degrees C. In the majori ty of patients, the differences (Tbr - Tbl and Tbr - Tre) were greater at temperatures outside of the normal temperature range (Tbr less tha n or equal to 36 degrees C and >38 degrees C). CONCLUSION: Tbl and Tre often underrepresent Tbr after traumatic brain injury, particularly w hen the patient is hypo- or hyperthermic.