Attempt to induce total-body hyperthermia by whole-abdominal hyperthermia using a radiofrequency capacitive-heating system: an experimental study in dogs.

The effects of whole-abdominal hyperthermia (WAH), using an 8 MHz radiofrequency capacitive-heating system, on the intraperitoneal and extraperitoneal distribution of heat and on the functions of visceral organs were studied. Eight female mongrel dogs were divided into two groups. Five were infused and three were not infused intraperitoneally with physiological saline. The mean increase in systemic temperature during WAH was 6.4 degrees C for the saline-infused group and 5.1 degrees C for the non-infused group. The systemic temperature reached 40 degrees C about 50 min after the start of heating in four of five animals in the saline-infused group; three of the four animals died, and in these the maximum temperature of the liver exceeded 43.5 degrees C. The infusion of saline into the peritoneal cavity may facilitate the elevation of systemic temperature. The effects on the liver of WAH were very marked, as analysed by biochemical and histological techniques. Visceral organs tolerated heating to less than 43 degrees C by WAH alone. It appears that elevation of the systemic temperature to 40.5 degrees C or more can be safely achieved under conditions where the temperature in the peritoneal cavity is kept below 43.5 degrees C during WAH.