Acute heat injury to the normal swine rectum

Intracavitary hyperthermia was applied to the rectum of normal pigs at 43 degrees, 44 degrees, 45 degrees, 46 degrees, 47 degrees and 48 degrees C for 30 min. A score of temperature-induced histological changes of each specimen was made 48 h after heating. The scores from each specimen and temperature were used for regression analysis. Judging from the regression lines of the scores obtained for rectum and oesophagus, we conclude that the thermosensitivity of the rectum is about 1 degree C higher than that of the oesophagus. It suggested that 43 degrees C/30 min could be a safe dose for normal rectum. The thermosensitivity of swine rectum is discussed.