The impact of intra-operative sufentanil dosing on post-operative pain, hyperalgesia and morphine consumption after cardiac surgery

Background There is an ongoing debate whether opioids when used for intra-operative analgesia may enhance post-operative pain. We studied the effect of two different intra-operative dosings of sufentanil on post-operative morphine consumption, pain and hyperalgesia after cardiac anaesthesia. Methods Forty-two male patients (age: 4874 years) undergoing first-time coronary artery bypass graft surgery were randomized to one of two groups receiving total intravenous anaesthesia with propofol and a target controlled infusion of sufentanil with a target of 0.4ng/mL (group SL, n=20) or 0.8ng/mL (group SH, n=22) plasma concentration. Post-operative morphine requirement in the first 48h was assessed using patient-controlled analgesia (PCA). Pain rating during deep inspiration, and the extent of primary and secondary hyperalgesia near the sternotomy wound were assessed. Results The post-operative morphine requirements in the first 48h were 0.68 +/- 0.21mg/kg in group SL and 0.96 +/- 0.44mg/kg in group SH (p<0.05). In group SL, pain during deep inspiration was significantly lower on the first post-operative day (p<0.05). Primary hyperalgesia had its maximum on the second and third post-operative day, without a difference between the two groups. The extent of secondary mechanical pinprick hyperalgesia was not different between the groups. Discussion Intra-operative dosing of sufentanil significantly influenced post-operative morphine consumption, pain and hyperalgesia. For cardiac anaesthesia in combination with propofol, a sufentanil target concentration of 0.4ng/mL may be preferable.