Metabolic and hemodynamic effects of high-dose insulin treatment in aortic valve and coronary surgery.
BACKGROUND
Glucose and insulin have been used as an adjuvant therapy in cardiac surgery because of their potentially beneficial effects on myocardial metabolism and contractile function. This study evaluated the effects of high-dose insulin on systemic metabolism and hemodynamics after combined heart surgery.


METHODS
Forty elective patients scheduled for combined aortic valve replacement and coronary artery bypass surgery were randomly assigned to receive either high-dose insulin treatment (short-acting insulin 1 IU.kg(-1).h(-1) with 30% glucose 1.5 mL.kg(-1).h(-1) administered separately) or control treatment (saline). The blood glucose levels were maintained within a targeted range by adjusting the rate of glucose infusion in the treatment group and by short-acting insulin bolus doses in the control group.


RESULTS
The lactate clearance was faster (p = 0.046), and the lactate levels (p = 0.016), blood glucose levels (p < 0.001), and free fatty acid levels (p < 0.001) were lower in the insulin group postoperatively. Besides, there was lesser need for dobutamine support (p = 0.013) and a trend toward better cardiac indices. Insulin treatment increased the respiratory quotient (p < 0.001), but there were no differences between the groups with regard to systemic oxygen consumption or energy expenditure measured by indirect calorimetry. The average glucose uptake in the insulin group was 7.1 g/kg in 24 hours (28 kcal.kg(-1).day(-1)).


CONCLUSIONS
The high-dose insulin treatment was associated with lower blood glucose levels, better preserved myocardial contractile function, and less need for inotropic support, and hence led to lower lactate levels postoperatively. The protocol is safe, but requires strict control of blood glucose level.
Koskenkari
Juha K
JK
Division of Intensive Care, Department of Anesthesiology, University of Oulu, Oulu, Finland. juha.koskenkari@fimnet.fi
Kaukoranta
Päivi K
PK
Kiviluoma
Kai T
KT
Raatikainen
M J Pekka
MJ
Ohtonen
Pasi P
PP
Ala-Kokko
Tero I
TI
D000368:Aged; D001024:Aortic Valve Stenosis / Q000601:surgery; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism*; D001026:Coronary Artery Bypass; D003324:Coronary Artery Disease / Q000601:surgery; D019918:Heart Valve Prosthesis Implantation; D006439:Hemodynamics; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D019344:Lactic Acid / Q000097:blood; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D010100:Oxygen / Q000097:blood; D011446:Prospective Studies
D015415:Biomarkers; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D007328:Insulin; D019344:Lactic Acid; D010100:Oxygen