AMINO ACID-ENRICHED GLUCOSE-INSULIN-POTASSIUM INFUSION IMPROVES HEMODYNAMIC FUNCTION AFTER CORONARY-BYPASS SURGERY - A DOUBLE-BLIND-STUDY IN PATIENTS WITH UNSTABLE ANGINA AND OR COMPROMISED LEFT-VENTRICULAR FUNCTION/

Objective: The goal of this study was to assess the effects of a combi nation of glucose-insulin-potassium (GIK) and the amino acids aspartat e and glutamate upon perioperative hemodynamics in coronary surgery pa tients with unstable angina and/or compromised left ventricular functi on. Design: Prospective, randomized, and double-blind clinical study. Setting: Operating theatre and intensive care unit (ICU) of a universi ty hospital. Patients: 44 coronary artery bypass graft (CABG) patients with unstable angina and/or compromised left ventricular function. In terventions: 22 patients (group A) were given 11 of an infusion with 2 50 g glucose, 100 I.U. fast-acting human insulin, 72 mmol potassium, 3 2 mmol magnesium, 20 mmol phosphate, 65 mmol aspartate, and 65 mmol gl utamate, while another 22 patients (group C) were given 11 of an infus ion with 50 g glucose, 72 mmol potassium, 32 mmol magnesium, and 8 mmo l phosphate. The infusion rate was 1.2 ml/kg/h from the anesthesia ind uction onward to the commencement of cardiopulmonary bypass, when it w as reduced to 0.8 ml/kg/h. When 11 had been infused, but not later tha n 4 a.m., the infusion was continued by giving 10% glucose at the same rate to both groups. Additional insulin (median: 14.2 I.U., range: 0- 41.5) or saline was given during bypass to the A and C patients, respe ctively. A blood cardioplegia technique containing aspartate and gluta mate was used in both groups. Results: At aortic cannulation, the card iac index (CI) had increased from the preanesthetic level by 15.3% (me an) (SD: 31.7%) in group A and decreased by 7.7% (15.1%) in C patients , p = 0.0069. Also the changes in stroke index (SI; p = 0.022), left ( LVSWI; p = 0.0037) and right ventricular stroke work index (RVSWI; p = 0.0097) were more favorable in group A. Despite longer aortic cross-c lamp, p = 0.031, and perfusion times, p = 0.042, in A patients, the ch ange in cardiac index was also better in this group after bypass: At d ecannulation, the difference between mean values was 31.8%, p = 0.0001 , and at arrival in the ICU it was 16.1%, p = 0.028. The same was also seen 8 h postoperatively and on the Ist and 2nd postoperative morning s; p = 0.034, 0.040, and 0.037, respectively (Wilcoxon test). Favorabl e changes were seen for the A patients also regarding SI at decannulat ion (p = 0.0002) and after 8 h (p = 0.017); LVSWI at decannulation (p = 0.0002), at arrival in the ICU (p = 0.0023), and after 8h (p = 0.001 1); and RVSWI at decannulation (p = 0.0027), at the ICU (p = 0.021), a fter 8 h (p = 0.014), and on the Ist postoperative morning (p = 0.039) . However, the response to a hemodynamic loading test (6% hydroxyethyl starch 5 ml/kg) was similar in the 2 groups, and there was no differe nce in the need for inotropic support. Conclusions: Amino acid-enriche d GIK infusion improves hemodynamic function in CABG patients with uns table angina and/or compromised left ventricular function.