Clinical Study On The Effect Of Esketamine On Rebound Pain After Brachial Plexus Block

Background:With the advancement of ultrasonic visualization technology,the application of peripheral nerve blocks has become increasingly widespread.Clinical studies have discovered that patients receiving peripheral nerve block anesthesia frequently experience severe pain following surgery,giving rise to the concept of rebound pain.Rebound pain typically manifests after the peripheral nerve block’s effects subside,with a NRS score of ≥7 and persisting for a brief duration of approximately 3～6 hours.During this time,opioid pain medication consumption escalates while proving less effective.The pathogenesis of rebound pain remains uncertain but may primarily be associated with the following factors: 1)neuropathic pain resulting from mechanical nerve injury;2)the impact of nerve block on pain pathways;3)neurotoxic effects of local anesthetics;4)non-adherent bridging analgesia treatment;5)patient cognition and education.Esketamine,when administered alone,can induce local anesthesia,and when combined with local anesthetics,can generate synergistic effects.Concerning the mechanism underlying rebound pain,esketamine,as an NMDA receptor antagonist,exhibits anti-inflammatory,neuroprotective,and algesthesia prevention properties.It can diminish the incidence of inflammatory reactions induced by surgery and nerve block,as well as alleviate neuropathic pain by obstructing large-conductance K+ channels.Consequently,this study postulated that the combination of esketamine and the local anesthetic ropivacaine could augment the nerve block’s efficacy and ameliorate the onset of rebound pain following a single supraclavicular brachial plexus block,and conduct relevant clinical studies.Objective:The aim of this study is to investigate the impact of esketamine combined with ropivacaine on rebound pain following a supraclavicular brachial plexus block,and to offer a reference for the clinical prevention and management of rebound pain after peripheral nerve block.Methods:Sixty patients who underwent upper extremity orthopedic surgery for a supraclavicular brachial plexus block between August 2022 and January 2023 were chosen and divided into a control group(group C)and an esketamine combined ropivacaine group(group E)using a random number table method.The local anesthetic mixture for group C consisted of 0.375% ropivacaine(20ml),while the local anesthetic mixture for group E was composed of 0.375% ropivacaine and 0.3mg/kg esketamine(20ml).An anesthesiologist with extensive experience in nerve blocks performed the ultrasound-guided supraclavicular brachial plexus block.Heart rate(HR)and mean arterial pressure(MAP)of the patients were recorded upon entering the room,5 minutes after completing the block,at the time of skin incision,30 minutes after the surgery,and at the end of the operation,as well as the onset time of sensory and motor nerve block.Postoperative follow-ups were conducted at 4h,6h,8h,10 h,12h,and 24 h intervals.The duration of sensory and motor block,the incidence and duration of rebound pain,resting pain scores(NRS-R),and movement pain scores(NRS-M)at each time point,the time of first analgesic pump compression,and the total sufentanil consumption within 24 h were documented.Adverse reactions and patient satisfaction were also assessed.Results:1.No statistically significant differences were observed in the HR,and MAP at each time point between the two groups(P > 0.05).2.No statistically significant differences were found in the onset time of sensory and motor nerve block between the two groups(P > 0.05).However,the duration of sensory and motor nerve block in group E was notably longer than in group C,with statistical significance(P < 0.05).The NRS-R/M scores of group C at 8h,10 h,and 12 h post-surgery were considerably higher than those of group E,and the difference was statistically significant(P < 0.05).In comparison to group C,the first compression time on PCIA for group E was significantly later,and the total consumption of sufentanil within 24 h in group E was significantly reduced,with statistical significance(P < 0.05).3.In comparison to the two groups,the incidence of rebound pain in group E was markedly lower than in group C,and the onset time of rebound pain in group E was significantly later than in group C,with statistical significance(P < 0.05).4.Comparing the incidence of postoperative adverse reactions between the two groups,the incidence of dizziness in group E was significantly higher than in group C,with statistical significance(P < 0.05).In contrast,patient satisfaction in group E was notably higher than in group C,with a statistically significant difference(P < 0.05).Conclusion0.3mg/kg Esketamine as ropivacaine adjuvant for supraclavicular brachial plexus block can prolong the duration of sensory and motor nerve block,effectively reduce the occurrence of postoperative rebounnd pain,delay the occurrence of rebounnd pain,improve postoperative analgesia,reduce the amount of sufentanil.