Effects of Graded Insulin Infusions on Plasma Levels of Free Fatty Acids, Adrenaline and Noradrenaline Directly After Open Heart Surgery

A four-hour insulin "clamp" technique was used to study the dose-response relationship between a wide range of plasma concentrations of insulin (5.0-7000 mU/l), free fatty acids, adrenaline and noradrenaline in 28 patients directly after open heart surgery. The influence of beta-blockers is discussed. All patients had elevated levels of free fatty acids at the beginning of the study (1020 +/- 77 mumol/l). After 4 hours the decline in free fatty acids was significant in all insulin-treated patients and most pronounced in the groups with insulin concentrations of more than approximately 350 mU/l, i.e. when insulin was infused with 0.3 units/kg bw/hour or more. No significant decrease in free fatty acids was observed in the control group. Adrenaline and noradrenaline in plasma were markedly increased throughout the study and were unaffected by the insulin infusions in all groups.