Abstract:

Objective To explore whether butorphanol tartrate as an adjuvant of ropivacaine for brachial plexus block can reduce the incidence of rebound pain after brachial plexus block. Methods Based on sample size calculation， 174 patients undergoing upper limb bone surgery were included in this study and randomized into three groups using statistical software： butorphanol tartrate compound local anesthetic （group B1）， brachial plexus block with 0.25% ropivacaine 20 mL （including adjuvant butorphanol 1mg）； intravenous butorphanol group （group B2）， brachial plexus block with 0.25% ropivacaine 20 mL， in addition， 1mg of butorphanol was administered i. v； control （group C）， only 0.25% ropivacaine 20ml for brachial plexus block. The patients were visited the day before operation， and the basic information of the patients was obtained. At the same time， the Douleur Neuropathique 4 questions （DN4） was used to evaluate whether there were neuropathic components （DN4 ≥ 4） in the site to be operated on， and the Numerical rating scale （NRS） was introduced to the patients， and the preoperative NRS value was obtained. 30 minutes before the operation， the same anesthesiologist with rich experience in nerve block completed the ultrasound-guided brachial plexus block （interscalene approach）， and tested whether the block effect was perfect. After entering the operating room， the patients were given general anesthesia， and the duration of operation， vital signs during operation， dosage of analgesics and whether or not using tourniquet were recorded. After the operation， the patients were sent to the postanesthesia care unit， and then sent to the ward when the patients reached the standard of leaving the room. Distribute pain diaries to patients and their families and instruct them to fill in relevant matters. The patients were followed up at 0 h， 6 h， 12 h， 18 h， 24 h and 36 h after operation to obtain the NRS value at each time point after operation， the time when the block disappeared and the highest NRS value within 12 hours， the first use of rescue analgesics， the use of postoperative analgesics， postoperative adverse events and the quality of patient recovery. Results The incidence of rebound pain was 31.6% in B1，48.2% in B2， and 54.4% in C. The pairwise comparison showed statistical difference between B1 and C （P < 0.05）. Rebound pain score in the three groups was B1 group < B2 group < C group and it was statistically different between the three groups（P < 0.05）. The pairwise comparison showed a statistical difference between B1 group and C group （P < 0.05）. Postoperative opioid consumption in Group C was greater than that in Group B1 and was statistically different （P < 0.05）.There was no statistically significant difference in NRS scores at each time point in the three groups and no difference in the area under the curve （NRS-AUC） of the pain curve at 0-6 hours and 6-24 hours after surgery （P > 0.05）. There were no statistical differences in the duration of motor block， sensory block duration， duration of analgesia， time to first request for rescue analgesia， and QoR-15 recovery quality score （P > 0.05）. There was no statistical difference in the incidence of postoperative adverse effects among the three groups （P > 0.05）. Conclusion This study found that brachial plexus block with 1mg butorphanol tartrate as an adjuvant for ropivacaine reduced the incidence of rebound pain and rebound pain scores after upper limb orthopedic surgery and reduced postoperative opioid consumption.

Key words: butorphanol tartrate, upper limb bone surgery, rebound pain, brachial plexus block