[The stress reaction in knee operations under continuous peridural anesthesia in comparison with neuroleptanalgesia]

30 patients undergoing knee-operations were randomized in two groups. 15 patients were operated on under neuroleptanalgesia. Piritramid was given postoperatively. The other group of patients was operated under epidural analgesia, postoperatively they were kept painfree by continuous infusion of 0.2% bupivacaine via an epidural catheter at a rate of 0.2 ml/kg.h over a period of 24 h. The aim of our study was to find out if continuous epidural anaesthesia in contrast to neurolept analgesia was able to prevent the hormoneal and metabolic response to these painful operations. Plasma glucose, insulin, C-peptidee, glucagon, cortisol, human growth hormon, and beta-hydroxybutyric acid were measured before commencing anaesthesia (point 0), after induction (point N), at the end of operation (point Op) and 1, 2, 4, 6, 12 and 24 h postoperatively (point 1, 2, 4, 6, 12 and 24). In both groups of patients an intravenous glucose tolerance test was carried out after 24 h. There were significant differences between the two groups in plasma glucose, insulin, C-peptid and cortisol, indicating that the stress response can be mitigated by continuous epidural anaesthesia. These differences however were only found in the first few postoperative hours. After a period of 24 h there were no differences at all, the metabolic alterations as indicated by the pathological glucose tolerance test, were the same in both groups, independent of the anaesthetic method used.