Effect of Glucose-Insulin-Potassium on Hyperlactatemia in Patients Undergoing Valvular Heart Surgery

Hyperlactatemia, occuring 10-20% in patients undergoing valvular heart surgery, is known to be associated with hemodynamic instability, organ dysfunction and increased postoperative morbidity and mortality. Glucose-Insulin-Potassium(GIK) has been constantly used as an adjuvant therapy in patients with myocardial infarction or in the patients undergoing valvular heart surgery to reduce the low cardiac output syndrome and mortality. GIK is known to prevent excretion of lactate and to increase the extraction of lactate after reperfusion with various mechanism. In addition, it is also known to decrease ischemic-reperfusion injury of myocardium after CPB, to improve myocardial contractility, insulin resistance and hyperglucemia. As a result, it brings hemodynamic stability and sufficient oxygen supply to the tissue, which might reduce the incidence of hyperlactatemia after valvular heart surgery.

Inclusion Criteria:

• patients(20 yr or older) undergoing elective valvular heart surgery under cardiopulmonary bypass(CPB) with more than 2 of following features:

  1. congestive heart failure
  2. infective endocarditis
  3. redo valvular surgery
  4. surgery combined with coronary bypass graft
  5. multiple valvular surgery
  6. expected CPB duration longer than 2 hr 7> preoperative serum creatinine over 1.4 mg/dl 8> preoperative hemoglobin level less than 12 mg/dl 9> left ventricular ejection fraction less than 40%

Exclusion Criteria:

1. emergency surgery
2. hemodynamic instability before surgery (mean arterial pressure < 60 mmHg, heart rate >100 /min
3. need for pharmacological or mechanical assist for hemodynamic stability before surgery
4. baseline blood lactate level more than 2 mmol/l
5. on steroid or NSAID
6. hepatic dysfunction