Influence of intraoperative remifentanil and sufentanil on sensory perception: a randomized trial

The clinical relevance of pro- and hyperalgesic effects of opioids is still a matter of debate. Particularly for remifentanil, an increased postoperative need for analgesics has been demonstrated suggesting opioid-induced hyperalgesia as a possible cause. The aim of the study was therefore to investigate the effect of intraoperatively applied remifentanil compared to sufentanil on somatosensory thresholds investigated with the quantitative sensory testing (QST) battery of the German Research Network on Neuropathic Pain (DFNS).

Twenty-three patients undergoing surgery of the female breast were randomly assigned to intraoperative remifentanil (0.4 μg × kg^-1 × min^-1) or sufentanil (0.25 μg × kg^-1 bolus, 0.15 μg × kg^-1, repetition after 60 min) application. Anesthesia was maintained BIS-guided (Bispectral index^TM) with propofol and postoperative analgesia was ensured with paracetamol (max. 3 g/24 h). Quantitative sensory testing was performed in the region of dermatome Th 5 in the mid-axillary line preoperatively and 20 h postoperatively.

The study was registered at the German registry for clinical studies (DRKS00009002).

Comparison of somatosensory thresholds before versus after surgery and application of intraoperative remifentanil or sufentanil.

Sixteen patients could be finally included in the analysis. No differences of mechanical or thermal detection or pain thresholds were observed between pre- and postoperative testing or between remifentanil and sufentanil.

A change of somatosensory thresholds or a clinically relevant opioid-induced hyperalgesia in the selected small patient sample (segmental resections or mastectomy with or without sentinel lymph node biopsy, surgery length <90 minutes, sufficient postoperative pain medication with paracetamol due to rather low postoperative pain intensities) with remifentanil or sufentanil was not detected 20 h after surgery.