Is skeletal muscle luxury perfusion the main hemodynamic effect of high-dose insulin in cardiac surgery?

Insulin, in combination with glucose and potassium (GIK), can be used in he art surgery to improve hemodynamic performance. This study evaluates the ro le of skeletal muscle vasodilation in hemodynamic effects of high-dose GIK therapy early after coronary surgery. Thirty-three male patients undergoing coronary artery bypass grafting were included in a prospective, randomized and controlled study. Eleven patients received infusions of mixed amino ac ids (11.4 g) and insulin solution (225 IU insulin, glucose with the glucose clamp technique, and potassium), 11 patients received infusions of mixed a mino acids (11.4 g) and 11 patients served as control subjects. During comb ined insulin and amino acid infusion, cardiac output increased by 13 +/- 3% (+0.6 +/- 0.2 L.min(-1)) and systemic vascular resistance decreased by 24 +/- 345 (- 320 +/- 46 dyn.s.cm(-5)). The changes differed from those in the control group (CO:-0.2 +/- 0.1 L.min(-1), p < 0.05; SVR: +136 +/- 42 dyn.s .cm(-5), p < 0.05). Changes in skeletal muscle perfusion and leg vascular r esistance did not differ significantly among the groups. At most, changes i n leg blood how could explain 40% of the changes in cardiac output. Skeleta l muscle luxury perfusion is not the main hemodynamic effect of high-dose i nsulin in the early postoperative period after coronary surgery.