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

To explore the effects of remifentanil gradual withdrawal on remifentanil induced postoperative hyperalgesia. 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 (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. There was no significant difference among the VAS and additional analgesics in three groups at 6 and 24 hours after operation (0.05). There was no significant difference among the MPT in three groups before operation (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 (12.6, 11.668, both 0.01). The MPT of group H at 6 h and 24 h after surgery was lower than that of group L (all 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 0.01). No correlation was observed between MPT and VAS scores or additional analgesics at 6 and 24 hours postoperatively (0.05). Remifentanil gradual withdrawal significantly alleviated intraoperative administration of remifentanil induced postoperative hyperalgesia in laparoscopic hysterectomy patients.