Reversal of Glucose-Insulin-Potassium-Induced Hyperglycemia by Aggressive Insulin Treatment in Postoperative Heart Failure

Abstract

Metabolic support with glucose-insulin-potassium (GIK) significantly reduces the morbidity and mortality of patients in cardiogenic shock after hypothermic ischemic arrest for aortocoronary bypass surgery. However, a small subset of these patients develops postoperative insulin resistance regardless of their preoperative diabetic status. Whether GIK directly contributes to higher mortality in these patients is unknown. We reviewed the records of 322 patients whose treatment for postoperative cardiogenic shock included GIK. Ten patients (3%) had postoperative hyperglycemia (serum glucose ≧250 mg/dl or 13.9 mmol/l) due to insulin resistance. These were compared to randomly selected GIK-treated, insulin-responsive patients (n = 10) and non-GIK-treated patients (n = 10) for comparison. The insulin-resistant patients required increasing amounts of regular insulin up to 130 U/h until blood glucose levels fell below 250 mg/dl. However, short-term outcomes (IABP support time, length of stay in ICU, 7-day mortality) for insulin- resistant patients were indistinguishable from those for insulin-responsive patients. These data indicate that postoperative iatrogenic hyperglycemia in patients after cardiopulmonary bypass may not be detrimental per se and is reversible when treated with supplemental insulin.