[Effect of GIK solution on the myocardial metabolism]

Effect of GIK solution (50% glucose 100 ml + insulin 20IU + KCl 20 mEq) infused in an hour on the myocardial metabolism was studied in the postoperative period following the open-heart surgery. Increase of arterial glucose, pyruvate, K+ and PCO2 and the decrease of pH was significant at the end of infusion. Increase of coronary sinus blood PCO2, myocardial oxygen extraction ratio for glucose and carbohydrate and the decrease of pH was highly significant. Myocardial oxygen extraction ratio for carbohydrate correlated significantly with the increase of coronary sinus blood PCO2 and the decrease of pH. Although the cardiac index correlated poorly with the myocardial oxygen extraction ratio for carbohydrate, a significant correlation was observed between the coronary arterial-sinus blood K+ difference and the coronary sinus blood PCO2, pH and myocardial oxygen extraction ratio for carbohydrate. It is suggested that the infused glucose with insulin and K+ was metabolized and degraded to CO2 and H2O quickly in the TCA cycle producing ATP and the rest was stored as glycogen with the uptake of K+ in the myocardium.