Comparison of remifentanil or fentanyl administration during isoflurane anesthesia for coronary artery bypass surgery.

BACKGROUND: The combination of inhalational agents with moderate doses of fentanyl is popular in cardiac anesthesia. Remifentanil is a new opioid metabolized by non-specific esterases. The aim of our study was to assess whether remifentanil may be superior to fentanyl during isoflurane anesthesia for coronary artery surgery. MATERIAL/METHODS: Forty patients aged 40-70 years with stable coronary artery disease were randomly allocated to two groups: remifentanil was used in 20 patients (group I) and fentanyl was used in 20 patients (group II). Induction of anesthesia was performed with remifentanil infusion (0.5 microg/kg/min) or a bolus dose of fentanyl (5 microg/kg) followed by a bolus of etomidate and pancuronium. Maintenance of anesthesia was provided by isoflurane and infusion of the study opioid, with the rate adjusted according to systolic blood pressure values. Hemodynamic parameters were registered before and after the induction of anesthesia, skin incision, sternotomy, aortic cannulation, termination of cardiopulmonary bypass, chest closure, and skin closure. RESULTS: Heart rate and mean arterial pressure values were significantly lower in the remifentanil group, while systemic vascular resistance was higher in the fentanyl group in the measurements taken before the initiation of cardiopulmonary bypass. No differences were found between groups in the values of mean pulmonary pressure, pulmonary artery wedge pressure and transpulmonary pressure gradient, central venous pressure, and cardiac index. CONCLUSIONS: Remifentanil is safe during inhalation anesthesia for coronary artery surgery and it appears to be more effective than fentanyl in blunting hemodynamic response before the initiation of cardiopulmonary bypass surgery.