Epidural analgesia improves postoperative nitrogen balance.

Postoperative nitrogen balance was monitored in twelve patients undergoing hysterectomy under either epidural analgesia or general anaesthesia. The mean cumulative five-day nitrogen losses were significantly lower after epidural analgesia than after general anaesthesia. Nitrogen sparing presumably results from inhibiting the stress-induced release of catabolic hormones, since epidural analgesia abolished postoperative hyperglycaemia and increase in plasma cortisol concentrations. No adverse effects of inhibiting the stress response were observed. Neurogenic stimuli thus play a crucial part in the catabolic response to surgery. Inhibiting the endocrine metabolic response to trauma by neurogenic blockade may reduce the morbidity precipitated in high-risk patients by the catabolic response to surgery.