Remifentanil provides better protection against noxious stimuli during cardiac surgery than alfentanil

Background and objective: We hypothesized that remifentanil-propofol cardiac anaesthesia, plus administration of pirinitramide (piritramide) upon cessation of the remifentanil infusion, would be associated with a shorter time to tracheal extubation than alfentanil-propofol anaesthesia, without the occurrence of major haemodynamic instability. Methods: Haemodynamic stability and recovery characteristics of two remifentanil infusion regimens (0.5 μg kg−1 min−1; 0.25 μg kg−1 min−1) were therefore compared with an alfentanil infusion regimen (1 μg kg−1 min−1), in combination with target-controlled infusion of propofol, in a randomized blinded trial in 75 coronary artery surgery patients. Results: Pirinitramide provided good postoperative analgesia without prolonging extubation times: median extubation time in minutes after stopping the opioid-sedative drugs was 300 in the higher-dose remifentanil group and 270 in the lower-dose remifentanil group and alfentanil group (P = 0.606). Significant time-by-treatment interactions were seen for systolic arterial pressure (P = 0.015), mean arterial pressure (P = 0.009) and diastolic arterial pressure (P = 0.006). No significant interaction (P = 0.489) and no constant treatment effect were seen for heart rate (P = 0.288). Time effects were highly significant (P < 0.0001) for all haemodynamic variables. Heart rate remained stable in all groups. In the higher-dose remifentanil group, blood pressure was significantly different and lower during surgery and in this group less bolus doses of the opioid-sedative drugs (P = 0.015) had to be given. Conclusion: The higher-dose remifentanil infusion provided superior suppression of haemodynamic responses to noxious stimuli with better haemodynamic stability.