Glucose-insulin-potassium infusion for myocardial protection during off-pump coronary artery surgery.
BACKGROUND
The purpose of this randomized, double-blind, placebo-controlled pilot study was to determine the effectiveness of an intravenous glucose-insulin-potassium (GIK) infusion in preventing myocardial damage and maintaining cardiac performance in patients undergoing "off-pump" myocardial revascularization.


METHODS
Forty-six adult patients undergoing elective off-pump coronary artery bypass received either normal saline or a GIK infusion immediately after the induction of anesthesia through the first 12 hours of intensive care unit convalescence. Measurements of blood glucose, circulating creatine kinase MB and troponin I concentrations, as well as cardiac index (CI) and mixed venous oxygen saturation (SvO2), were obtained immediately before starting the infusion (baseline) and at 6, 12, and 24 hours post-initial coronary artery occlusion.


RESULTS
Five patients (8%) requiring cardiopulmonary bypass were excluded from data analysis. Twenty patients received saline. Twenty-one received GIK. Blood glucose was significantly higher in the GIK group. The concentration of circulating creatine kinase MB and troponin I significantly increased over time after off-pump coronary artery bypass, with no significant intergroup differences. Cardiac index and SvO2 did not differ significantly between groups.


CONCLUSIONS
A GIK infusion protocol commonly used as an adjunct to reperfusion therapy for acute myocardial infarction causes insulin-resistant hyperglycemia in elective off-pump coronary artery bypass patients with no demonstrable benefit. The finding of significant release of cardio-specific enzymes in individual patients implies an ongoing need to develop more effective strategies for myocardial protection during off-pump coronary artery bypass.
Lell
William A
WA
Department of Anesthesiology, The University of Alabama at Birmingham, 35249-6810, USA. william.lell@ccc.uab.edu
Nielsen
Vance G
VG
McGiffin
David C
DC
Schmidt
Frank E
FE
Kirklin
James K
JK
Stanley
Alfred W
AW
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D002302:Cardiac Output; D002314:Cardioplegic Solutions / Q000008:administration & dosage*; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass / Q000379:methods; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form; D004311:Double-Blind Method; D005260:Female; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000008:administration & dosage*; D007527:Isoenzymes / Q000097:blood; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D010865:Pilot Projects; D011188:Potassium / Q000008:administration & dosage*; D019210:Troponin I / Q000097:blood
D001786:Blood Glucose; D002314:Cardioplegic Solutions; D007328:Insulin; D007527:Isoenzymes; D019210:Troponin I; C030396:glucose-insulin-potassium cardioplegic solution; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form; D005947:Glucose; D011188:Potassium; D010100:Oxygen