Independence of brain and tympanic temperatures in an unanesthetized human

Abstract

Temperature within the brain and the esophagus and at the tympanum were obtained in a 12-yr-old male in a series of experiments that began 8 days after surgery for implantation of a drainage catheter. Fanning the face did reduce tympanic temperature but not temperature in the brain; brain temperatures followed esophageal temperatures. In long-term monitoring, temperature in the lateral ventricle was 0.5 degree C above esophageal temperature and 0.2 degree C below that in white matter 1 cm above, with the offsets fixed throughout the overnight cycle. All temperatures went through similar excursions when the face was excluded from fanning applied to the body. These observations highlight the fact that in humans the defense against hyperthermia takes advantage of cooling distributed over the entire skin surface.

Brain Temperature Measured Using Proton MR Spectroscopy Detects Cerebral Hemodynamic Impairment in Patients With Unilateral Chronic Major Cerebral Artery Steno-Occlusive Disease

“…20 BT is affected by body temperature, but not by ambient temperature. 21 Thus, whether cerebral hemodynamic impairment in patients with bilateral major cerebral artery occlusive disease can be detected using the absolute BT remains unclear. Third, a single-voxel ROI for measurement of BT was placed on the slice through the centrum semiovale.…”

Validation of Two Temperature Pill Telemetry Systems in Humans During Moderate and Strenuous Exercise

“…The first of these criteria, that the measured temperature reflect brain temperature, has been addressed by several investigators (1, 2,7,22,23). In 1951, Eichna et al (7) reasoned that the temperature of blood in the left ventricle would be the best approximation of what they called 'critical deep tissue' temperature.…”

“…The main detraction for using tympanic temperature is that It more reliably tracks skin temperature than core temperature in humans (9,21,22). This bias makes tympanic temperature an unreliable index of brain temperature (23), while esophageal temperature effectively tracks brain temperature. The disagreement among researchers is in part due to the effective insulation around the tympanic thermocouple.…”

Tympanic temperature measurements: Are they reliable in the critically ill? A clinical study of measures of agreement*

“…The speed, ease of use, and noninvasiveness has recommended its widespread application. Although commonly referred to as tympanic thermometry, it is quite different from direct tympanic thermometry (7,9), a "good index of core temperature" (10), in which measurements are made using direct contact on the tympanic membrane by an electronic probe (10). A number of studies (4,5,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) have compared the various modes of thermometry (including axillary readings) with inconsistent results; the "best" method still being considered a "continuing question" (10).…”