Effect of glucose-insulin-potassium on hyperlactataemia in patients undergoing valvular heart surgery: A randomised controlled study

Abstract

BACKGROUND: Hyperlactataemia represents oxygen imbalance in the tissues and its occurrence during cardiac surgery is associated with adverse outcomes. Glucose-insulin-potassium (GIK) infusion confers myocardial protection against ischaemia-reperfusion injury and has the potential to reduce lactate release while improving its clearance.

OBJECTIVES: The objective of this study is to compare the effect of GIK on the incidence of hyperlactataemia in patients undergoing valvular heart surgery.

DESIGN: A randomised controlled study.

SETTING: Single university teaching hospital.

PATIENTS: One hundred and six patients scheduled for elective valvular heart surgery with at least two of the known risk factors for hyperlactataemia.

INTERVENTION: Patients were randomly allocated to receive either GIK solution (insulin 0.1 IU kg(-1) h(-1) and an infusion of 30% dextrose and 80 mmol l(-1) potassium at 0.5 ml kg(-1) h(-1)) or 0.9% saline (control) throughout surgery.

MAIN OUTCOME MEASURES: The primary outcome was the incidence of hyperlactataemia (lactate ≥ 4 mmol l(-1)) during the operation and until 24 h after the operation. Secondary outcomes included haemodynamic parameters, use of vasopressor or inotropic drugs, and fluid balance until 24 h postoperatively. Postoperative morbidity endpoints were also assessed.

RESULTS: The incidences of hyperlactataemia were similar in the groups (32/53 patients in each of the control and GIK groups, P > 0.999). There were no intergroup differences in haemodynamic parameters, use of vasopressor and inotropic drugs, or fluid balance. The incidences of postoperative morbidity endpoints were similar in both groups.

CONCLUSION: Despite its theoretical advantage, GIK did not provide beneficial effects in terms of the incidence of hyperlactataemia or outcome in patients undergoing valvular heart surgery.