[No potentiation of fentanyl by use of transdermal buprenorphine in patients undergoing fast-track anesthesia for open-heart surgery].

OBJECTIVE

Simultaneous use of opioids with a different pharmacological profile may lead to unexpected prolongation of effects. In an open label study possible overhang in post-operative respiratory effects and vigilance was determined in a group of patients (n = 22) carrying a transdermal buprenorphine patch for at least 2 months for treatment of chronic pain, undergoing a fentanyl-based fast-track enflurane anesthetic technique for open-heart operation. Data was compared with another randomised group (n = 21) undergoing similar open-heart procedures with no other opioid than fentanyl on board.

METHODS AND

RESULTS

Following induction with fentanyl and a barbiturate, depth of anesthesia with enflurane (Fi 0.5) was guided using the bispectral index (BIS). Additional doses of fentanyl were given when blood pressure and/or heart-rate increased 20% above pre-induction levels. Early postoperative extubation was initiated once the cardiovascular system was stable and there were no signs of respiratory impairment. Following a similar time of operation and anesthesia and a similar total dose of fentanyl (0.69 mg +/- 0.23 SD versus 0.67 mg +/- 0.16 SD), postoperatively, there were no significant differences between the buprenorphine- and the control group regarding the time till extubation (25.2 min +/- 6.1 versus 33.3 min +/- 5.0) and the arterial blood gases under oxygen inhalation (paO2 136 torr +/- 48 SD versus 128 torr +/- 35 SD; paCO2 43.3 torr +/- 3.3 SD versus 41.9 torr +/- 1.2 SD and the post-anesthetic vigilance and recovery score (6.8 +/- 1.0 versus 7.5 +/- 0.8) 60 minutes after end of anesthesia. Contrary to the control group, there was a lower and significant (p < 0.01) incidence of PONV in patients with transdermal buprenorphine.

CONCLUSION

Patients using a buprenorphine patch for the relief of chronic pain cannot be regarded as opioid naïve. Due to adaptive mechanisms and the development of tolerance, there is no prolongation of the respiratory depression induced by intraoperative fentanyl. Long-term use of transdermal buprenorphine does not lead to potentiation or prolongation of opioid effects in cardiac surgery patients.