Effect of epidural analgesia on the glycoregulatory endocrine response to surgery

Plasma concentrations of glucose, insulin, glucagon, cortisol, growth hormone and prolactin were measured repeatedly in ten females undergoing abdominal hysterectomy during general anaesthesia. In addition to general anaesthesia five of the patients had continuous epidural analgesia effective for the first 26 postoperative hours. Plasma glucose was elevated during surgery and postoperatively, but not in patients having epidural analgesia. Insulin was low and unchanged in both groups. Glucagon was unchanged and similar in both groups. Cortisol was lower during surgery in the epidural group, but not postoperatively. Growth hormone increased during surgery in four of five patients receiving general anaesthesia alone, but no changes were observed in the epidural group. Prolactin was greatly elevated in all patients immediately after induction of anaesthesia and then fell rapidly during surgery, similarly in both groups. It is concluded that epidural analgesia can inhibit the hyperglycaemic response to surgical stress, but this effect cannot be uniformly correlated to changes in peripheral plasma levels of insulin, glucagon, cortisol, growth hormone or prolactin.