Does isoflurane optimize myocardial protection during cardiopulmonary bypass?

To investigate the possible myocardial protective effect of isoflurane during aortic cross-clamp and cardioplegic cardiac arrest in patients undergoing conventional coronary artery bypass graft surgery.

Prospective, randomized.

University medical center.

Forty-nine patients undergoing elective coronary artery bypass graft surgery divided into 2 groups: control group (n = 21) and isoflurane group (n = 28).

Isoflurane was administered in the pre-cardiopulmonary bypass (CPB) period to the isoflurane group.

Hemodynamics and ST- segment variations were monitored in the pre-CPB period and after weaning from CPB in both groups. Incidence of reperfusion arrhythmias after release of aortic cross-clamp was compared. In the isoflurane group, the mean cardiac index after CPB was significantly higher than the pre-CPB value, whereas no difference between the 2 values was found in the control group. The higher cardiac index in the isoflurane group was associated with a lesser degree of ST- segment changes than in the control group. There was no significant difference between the 2 groups in the incidence of reperfusion arrhythmias after release of aortic cross-clamp.

The present report suggests that administration of isoflurane before aortic cross-clamping in patients undergoing coronary artery bypass graft surgery may optimize the myocardial protective effect of cardioplegia. Isoflurane may be particularly advantageous whenever prolonged periods of aortic cross-clamping or inadequate delivery of cardioplegia is expected.