Midazolam modifies pancreatic and anterior pituitary hormone secretion during upper abdominal surgery

We have investigated the effects of midazolam on circulating concentrations of pituitary and pancreatic hormones in eight healthy patients during cholecystectomy and compared the changes with those in a control group of eight patients. Anaesthesia was induced either with midazolam 0.42 mg kg-1 i.v. followed by an infusion of midazolam 0.125 mg kg-1 for 1 h, or with a sleep dose of thiopentone. All patients received vecuronium, and the lungs were ventilated with 0.5-1.0% halothane and 70% nitrous oxide in oxygen. The use of midazolam was associated with a significant decrease (P less than 0.05) in secretion of cortisol and insulin during surgery. Serum growth hormone secretion was augmented, but this did not reach statistical significance. There was little difference in the concentrations of circulating metabolites between the two groups, except for a significant decrease in blood glucose (P less than 0.05) in the midazolam group after 60 min. There were no marked differences in cardiovascular variables between the two groups of patients.