The management of insulin dependent diabetes during cardiopulmonary bypass and general surgery.

Abstract

Two groups of insulin dependent diabetic subjects have been studied: six undergoing general surgical procedures and six undergoing hypothermic cardiopulmonary bypass surgery for coronary artery vein grafting. Intravenous glucose insulin mixtures were infused from the onset of surgery in both groups of patients, supplying 0.4 units of insulin per gram of glucose per hour, and 0.6 units of insulin per gram of glucose per hour in general and cardiac surgical patients respectively. Postoperatively diabetes was controlled carefully with an insulin syringe pump regulated by venous blood glucose monitoring. In cardiac surgical patients far more insulin was required to control diabetes postoperatively than in the general surgery patients (at 1 hour 1.6 units, SEM 0.4 compared to 0.7 SEM 0.1, p less than 0.05; and at 4 hours 2.0 units SEM 0.3 compared to 0.8 units SEM 0.1, p less than 0.02). Five non-diabetic subjects who underwent surgery for coronary artery venous bypass grafting were also studied. They developed significant postoperative hyperglycaemia (5.0, SEM 0.2, mmol/litre pre-operatively, compared with 8.8, SEM 0.7, mmol/litre p less than 0.03 at 1 hour and 10.2, SEM 1.7, mmol/litre, p less than 0.02 at 4 hours after bypass terminated).