Remifentanil vs fentanyl/morphine for pain and stress control during pediatric cardiac surgery.

Background: Remifentanil is a short acting, potent synthetic opioid that does not accumulate after infusion or repeated bolus doses. It may be rapidly titrated to the requirements of individual patients. Titrated infusion of remifentanil may be able to provide potent analgesia required for pediatric cardiac surgery and obtund the stress response in theater whilst not having the persistent respiratory depression and sedation seen with longer acting opioids.

Methods: Twenty patients were randomized to receive a titrated infusion of remifentanil (0-1 microg x kg(-1) x min(-1)) or a standard dose of fentanyl (30 microg x kg(-1)) prebypass plus morphine (1 mg x kg(-1)) on rewarming. Blood samples for glucose and cortisol were taken at regular intervals from induction through bypass and into the first 24 h of postoperative intensive care. In addition to biochemical indicators of the stress response we recorded baseline hemodynamic parameters and any acute physiological events.

Results: Ten patients received morphine, seven received remifentanil. There were no statistically significant differences between the two treatment groups in cortisol measurements, mean arterial pressure or heart rate recordings. In the last time period the remifentanil group had a larger rise in blood glucose concentration (baseline 3.9, rise 3 mmol x l(-1)) than the fentanyl/morphine group (baseline 4.2 rise 1.9 mmol x l(-1)), CI -4.3 to -0.2.

Conclusions: The only significant difference was in glucose in the postbypass time periods. Although statistically significant, this difference is insufficient evidence of increased stress in the remifentanil group. The results show that in the patients studied there was no clinically important difference between the two techniques.