Influence of neural pathways on the pyrexial response to surgical trauma

Epidural analgesia inhibits several metabolic effects of trauma. Some of these effects are generated by the endogenous fever mediator interleukin-1. Postoperative fever was therefore studied in 52 patients, 25 of whom had had epidural analgesia and 27 general anaesthesia. Transvesical prostatectomy was used as standard surgical trauma. Most of the patients had postoperative temperature rise exceeding 0.5 degree C, but the rise was not influenced by epidural analgesia. These data suggest that the release of endogenous fever mediator is not under control of afferent pathways from the region of trauma. The findings are also consistent with regulation of interleukin-1 release which is independent of adrenal stimulation, cyclic AMP or beta-endorphin, as epidural analgesia prevents postoperative increase of these hormones.