Effect of severity of surgery on metabolic control and insulin requirements in insulin-dependent diabetic patients

We have evaluated insulin requirements and the relationship between hormonal variables, changes in blood glucose and insulin requirements in insulin-dependent diabetic patients undergoing two degrees of severity of surgery: minor (vitrectomy) and major (gastrectomy, bowel resection, hip replacement). The study began just before induction and ended 2 h after surgery. Blood glucose concentrations were comparable in both groups but the total amount of insulin given was significantly greater in the major surgery group. Plasma noradrenaline and cortisol concentrations increased significantly during major surgery and there were significant correlations between the increase in these counter-regulatory hormones and the amount of insulin administered. We conclude that the metabolic changes occurring during surgery were small, but at the cost of a marked increase in insulin requirements during major surgery. Increased sympathetic nervous system activity seems to have been implicated in the increase in insulin requirements.