RATIONALE FOR METABOLIC SUPPORT WITH AMINO-ACIDS AND GLUCOSE-INSULIN-POTASSIUM (GIK) IN CARDIAC-SURGERY

Myocardial metabolism and the current state of metabolic intervention under conditions relevant to cardiac surgery are reviewed. The rationa le for metabolic support differs considerably in various settings of c ardiac surgery. Although preventive measures are theoretically attract ive, their use in the preoperative setting remains to be clarified. Am ino acid enrichment of blood cardioplegia seems to be justified by an abundance of animal experimental data. In the postoperative setting of cardiac surgery, metabolic abnormalities may explain reversible myoca rdial dysfunction. Further, the combined effects of ischemia and the s ystemic neuroendocrine response to surgical trauma may adversely affec t recovery. Amino acids, particularly glutamate, seem vital for metabo lic recovery in this setting. Treating the relative shortage of glutam ate occurring during this period by the administration of exogenous gl utamate and counteracting the effects of the systemic neuroendocrine s tress response by high-dose glucose-insulin-potassium are measures tha t have been shown to improve the metabolic state of the heart and subs equently myocardial performance.