[Effects of remifentanil gradual withdrawal on remifentanil induced postoperative hyperalgesia]

Abstract

Objective: To explore the effects of remifentanil gradual withdrawal on remifentanil induced postoperative hyperalgesia. Methods: Ninety patients from January to June 2018 undergoing elective laparoscopic hysterectomy under general anaesthesia at Ningbo NO.2 hospital, ASA Ⅰ or Ⅱ grade, aged 20-60, were enrolled in this study and randomly assigned to 3 groups (n=30): Group L (low dose remifentanil), Group H (high dose remifentanil) and Group G (high dose remifentanil with gradual withdrawal). Mechanical pain thresholds (MPT), visual analogue scale (VAS) and additional analgesics were recorded at 6 and 24 hours after the operation. Results: There was no significant difference among the VAS and additional analgesics in three groups at 6 and 24 hours after operation (P>0.05). There was no significant difference among the MPT in three groups before operation (P>0.05). The MPT of group L, group H and group G were (49.8±12.2), (35.5±13.0) and (48.6±11.4) g at 6 hours after surgery, and (51.4±14.3), (36.9±11.1) and (48.8±11.5) g at 24 hours after surgery, respectively, with statistically significant differences (F=12.6, 11.668, both P<0.01). The MPT of group H at 6 h and 24 h after surgery was lower than that of group L (all P<0.01), while the MPT of group G at 6 h and 24 h after surgery was significantly higher than that of group H (all P<0.01). No correlation was observed between MPT and VAS scores or additional analgesics at 6 and 24 hours postoperatively (P>0.05). Conclusion: Remifentanil gradual withdrawal significantly alleviated intraoperative administration of remifentanil induced postoperative hyperalgesia in laparoscopic hysterectomy patients.

Keywords: Hyperalgesia; Pain, postoperative; Remifentanil.