| Part 1 Cross-sectional area of the supraclavicular brachial plexusObjective:At present,Supraclavicular brachial plexus block(SCBPB)still requires a large dose of local anesthesia,which increases the risk of anesthesia.The purpose of this study is to explore the correlation between the Cross-sectional area(CSA)of the supraclavicular brachial plexus and demography,and to find the factors strongly related to CSA,so as to determine the dose of local anesthetic drugs.Methods:Group N included 80 patients who underwent elective surgery and were divided into young group(19-35 years),middle-aged group(36-59 years),and elderly group(60-64 years).The CSA of supraclavicular brachial plexus was calculated by scanning bilateral supraclavicular brachial plexus in all patients.If the CSA of supraclavicular brachial plexus could not be measured for other reasons such as unclear boundary or non-cooperation of patients,this side was excluded from the study.Demographic factors and CSA of supraclavicular brachial plexus were analyzed and univariate linear regression was performed in group N.Results:Ultrasound scan of bilateral supraclavicular regions of 80 patients in group N obtained 127 images of supraclavicular regions(33 sides were not measured),the cross-sectional area of supraclavicular brachial plexus was 78.± 14.9mm2,and the cross-sectional area of supraclavicular brachial plexus was 78.± 14.9mm2.The CSA of supraclavicular brachial plexus was positively correlated with the height(r=0.48),weight(r=0.41)and BMI(r=0.24)of the patients.There is no significant correlation between age and CSA of nerve,and there is no significant difference between CSA of supraclavicular brachial plexus nerve in different age groups,there is no difference between CSA of left and right supraclavicular nerve,and there is difference between CSA of supraclavicular brachial plexus nerve in different sexes.There were blood vessels perpendicular or parallel to the nerve sonogram in the supraclavicular brachial plexus.Conclusions:There is no strong correlation between demographic factors and CSA of supracavian brachial plexus,and there are also large differences between genders,which can not provide a reference for drug dose of ultrasound-guided SCBPB.Therefore,it is necessary to study the drug dose-nerve cross-sectional area effect.Part Ⅱ The ED90 of Ultrasound-guided supraclavicular brachial plexus block with 0.5%ropivacaineObjective:The first part of the study found that demographic factors could not provide a good reference for the dose of SCBPB.Therefore,this study will directly explore the ED90 of SCBPB with 0.5%ropivacaine under ultrasound guidance based on CSA,in order to reduce the dose of local anesthesia during SCBPB and improve the safety of anesthesia.Methods:At least 45 patients scheduled for elective forearm or hand surgery were included in group O.We in light ofthe biased coin design up-and-down,sequential method(BCD-UDM),the first patient was given 0.5 ropivacaine 0.18 ml/mm2,and the second patient was given 0.5 ropivacaine 0.18 ml/mm2.With complete sensory block in the brachial plexus control area within 30 minutes,which was defined as successful,the next patient had an 89%chance of maintaining the same dose and an 11%chance of a lower dose level of 0.04ml per cubic meter until the trial was stopped at 45 positive successful blocks.The ED90 and 95%confidence intervals(CI 95%),ED50 and ED90 of ultrasound-guided SCBPB with 0.5%ropivacaine per unit area were calculated by central ordinal preserving regression for patients in group O.Results:The ED90 and 95%confidence interval of SPBPB with 0.5%ropivacaine per unit area were 0.189 ml/mm2(CI 95%0.176ml/mm2,0.225ml/mm2),ED50 and ED99 were 0.163 ml/mm2,respectively.0.251 ml/mm2.Conclusions:Ultrasound-guided SCBPB with 0.5%ropivacaine at a dose of 0.189 ml/mm2 can achieve satisfactory anesthesia effect. |
