Stepwise tapering of remifentanil at the end of surgery decreased postoperative pain and the need of rescue analgesics after thyroidectomy

BACKGROUND This study was designed to investigate whether stepwise tapering of remifentanil at the end of surgery could decrease postoperative pain scores and requirements of rescue analgesics after remifentanil-desflurane anesthesia in patients with thyroidectomy. METHODS Sixty two patients undergoing thyroidectomy under general anesthesia were randomly allocated into two groups. All patients were anesthetised with desflurane and high-dose remifentanil. Remifentnail was infused at the rate of 0.3 μg/kg/min until the end of surgery in patients of the control group (group A) whereas remifentanil was tapered gradually from 0.3 to 0.1 μg/kg/min until the end of surgery for at least 30 minutes in patients with group B. Pain scores (0-100 numerical rating scale, NRS), rescue analgesic requirements and adverse events were assessed at 30 min, 2 h, 6 h, 12 h, and 24 h after operation. RESULTS There was a significant decrease in pain scores at 30 min (20 [0-80] vs. 50 [0-100], P = 0.002) and 2 h (30 [10-60] vs. 40 [20-80], P = 0.018) after surgery in group B compared with group A. In addition, rescue analgesics are less required in group B than in group A postoperatively (2 [1-3] vs. 3 [2,3], P = 0.039). There were no significant differences in adverse events between the two groups. CONCLUSIONS Tapering of remifentanil at the end of surgery decreased postoperative pain scores immediately after thyroidectomy with desflurane and high-dose remifentanil anesthesia. TRIAL REGISTRATION Clinical Research information Service (CRiS, registration number KCT0000589).