Cerebral temperature and epidural pressure during whole body hyperthermia in dogs.

Whole body hyperthermia was performed on 13 anaesthetized and intubated dogs. Cerebral temperature and epidural pressure were measured and related to rectal and oesophageal temperatures. The brain temperature was significantly higher than that of the rectum at normotemperature. The temperature gradients lessened during heating. At maximum rectal temperature (plateau) small differences between the left and right hand sides of the brain were seen, the temperatures being 0.4 degrees C and 0.3 degrees C higher than the rectal temperature, respectively. During the 2-h plateau period the difference between brain and oesophageal temperature became progressively smaller. The mean epidural pressure decreased slightly during the course of the treatment, but remained within the normal range of 1.2 +/- 0.4 KPa (8.7 +/- 2.5 mm Hg). From this investigation may be concluded that (1) the cerebral temperature is reflected better by the oesophageal than by the rectal temperature and (2) the epidural pressure does not increase during whole body hyperthermia for 2 h at a rectal temperature of up to 42.5 degrees C.