| Objectives:At present,dexmedetomidine hydrochloride has been widely used as an adjuvant to local anesthetics in clinical nerve block anesthesia,so as to shorten the onset time of peripheral nerve block and prolong the analgesic time of peripheral nerve block.However,the effect of dexmedetomidine for brachial plexus block,especially supraclavicular brachial plexus block(SBPB)with different application doses has been controversial in different literatures,and with the doses of application increasing gradually,there has been no evidence of a safety threshold.We integrated high quality literatures at home and abroad for the first time to study the effects and side effects of three different doses of dexmedetomidine hydrochloride combined with ropivacaine hydrochloride for supraclavicular brachial plexus block,thus to optimize the medications of nerve block and achieve more ideal peripheral nerve block anesthesia and postoperative analgesia so that provide advice or evidence-based evidence.Methods:We searched all the clinical randomized controlled trials literatures of dexmedetomidine hydrochloride combined with ropivacaine hydrochloride for supraclavicular brachial plexus block from China National Knowledge Internet(CNKI)、WANFANG medical network、Google Scholar、VIP network,Pub Med,Embase Cochrane Library and web of science from computer.The deadline is september 30,2019.At the same time,we manually searched the references of the included literatures.We screened the literatures according to the inclusion and exclusion criteria and extracted the data based on the content,and then two independent researchers used Cochrane qualityassessment tools to evaluate the literature in terms of methodological quality,after using Rev Man 5.3 software to Meta analysis,that the GRADE system was used to evaluate the quality of evidence.We comprehensively analyzed the efficacy and safety of dexmedetomidine from the aspects of onset time,duration and analgesic time of sensory and motor block in supraclavicular brachial plexus nerve block,as well as the occurrence of side effects such as bradycardia,hypotension and excessive sedation.Results:1 Main indicators 11 RCTs were included in this Meta-analysis,The main indicators included onset time,duration and analgesic time of SBPB.1.1 The results showed that dexmedetomidine(DEX)combined with ropivacaine for SBPB could shorten the onset time of sensory nerve block(standardized mean difference(SMD),-1.30,95% confidence Interval(CI)was-1.86 to-0.73,P<0.00001),and subgroup analysis showed that the adjuvant dose of 50μg and 1μg/kg had statistical significance in shortening onset time of SBPB(50μg:SMD-1.94,95%CI-3.00～-0.88,P=0.0003;1μg/kg: SMD-0.96,95%CI-1.74～-0.18,P=0.02),while no statistical difference was found in the group of 100μg in intra-group comparison(SMD-0.93,95%CI-2.58～0.71,P=0.27).1.2 The results showed that the addition of DEX to ropivacaine for SBPB prolonged the duration of sensory blockade(SMD 3.09,95%CI 2.13～4.06,P<0.00001),and subgroup analysis showed that the data of different dose had statistical significance in prolonging the duration of sensory blockade(50μg:SMD 5.83,95%CI 2.67～8.99,P=0.0003;1μg/kg:SMD 1.84,95%CI 0.84～2.84,P= 0.0003;100μg:SMD 2.94,95%CI 1.58～4.30,P< 0.0001).1.3 The results showed that the addition of DEX to ropivacaine for SBPB could shorten the onset time of motor nerve block(SMD-1.06,95%CI-1.48～-0.64,P<0.00001).Subgroup analysis showed that the adjuvant dose of50μg and 1μg/kg had statistical significance in shortening the onset time of SBPB(50μg:SMD-1.41,95%CI-2.14～-0.67,P=0.0002;1μg/kg:SMD-0.95,95%CI-1.63～-0.26,P=0.007),while no statistical difference was found in thegroup of 100μg in intra-group comparison(100μg:SMD-0.69,95%CI-1.60～0.22,P=0.14).1.4 The results showed that the addition of DEX to ropivacaine for SBPB prolonged the duration of motor nerve block(SMD 2.69,95%CI 1.79～3.58,P<0.00001),and subgroup analysis showed that the dose of 50μg and1μg/kg had statistical significance for prolonging motor block time of SBPB(50μg:SMD 6.15,95%CI 3.05～9.26,P=0.0001;1μg/kg:SMD 1.75,95%CI 0.83～2.68,P=0.0002),while no statistical difference was found in the group of100μg in intra-group comparison(100μg:SMD 1.46,95%CI-0.27～3.19,P=0.10).1.5 The results showed that the addition of DEX to ropivacaine for SBPB prolonged the analgesia time(SMD 2.66,95%CI 1.42～3.89,P<0.0001),subgroup analysis showed that adjuvant dose of 50μg and 1μg/kg prolonged the SBPB analgesia time,with certain statistical significance(50μg:SMD 4.66,95%CI 0.91～8.42,P=0.01;1μg/kg: SMD 1.93,95%CI 1.01～2.86,P<0.0001),while no statistical difference was found in the group of 100μg in intra-group comparison(100μg:SMD 1.36,95%CI-3.10～5.83,P=0.55).2 Secondary indicators(side effects)The occurrence of hypotension,bradycardia and excessive sedation with three doses of dexmedetomidine in ropivacaine for supravicular brachial plexus block was not statistically significant compared with that without adjuvant(Hypotension:Risk difference(RD)0.00,95%CI-0.02～0.02,P=0.81;Bradycardia:RD 0.01,95%CI-0.01～0.03,P=0.48;Excessive sedation:RD 0.00,95%CI-0.02～0.02,P=0.71)Conclusions:Compared with ropivacaine alone,adding DEX of 50μg and 1μg/kg to SBPB could significantly shorten the onset time of sensory and motor block and prolong the duration of sensory and motor block and analgesic time without increasing the risk of side effects,such as bradycardia,hypotension and excessive sedation.In addition to prolonging the duration of sensory block,dexmedetomidine adjuvant with increased dose to 100μg showed noimprovement in clinical effect,but also no increased risk of side effects.For the characteristics and advantages of dexmedetomidine as an adjuvant,we infer that the addition of DEX with less than 100μg to SBPB can achieve the effect of assisting anesthesia and postoperative analgesia,and clinical applications do not necessarily pursue large doses to achieve the purpose of assisting anesthesia and postoperative analgesia,but specific conclusion still needs a lot of clinical trials to further analysis conclusion. |
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