Comparison Of Effects Of Different Concentrations Of Ropivacaine Mixed With Dexmedetomidine Quadratus Lumborum Block For Total Hip Replacement In Elderly Patients Under General Anesthesia

Objective : To compare the effect of mixed dexmedetomide with different concentrations of ropivacaine on the quadratus lumborum block for elderly patients with total hip replacement.Methods : 60 patients with unilateral total hip arthroplasty were selected from May 2019 to January 2020,including 27 males and 33 females,aged 65～85 yr,Weighing 40～80kg,American Society of Anesthesiologists(ASA)physical status II or III.They were randomly divided into two groups groups: 0.33% Ropivacaine with 1 μg/kg dexmedetomidine group(R1 group)and 0.25% ropivacaine group with 1μg/kg dexmedetomidine group(R2 group),30 cases in each group.Before induction of anesthesia,the R1 group and the R2 group used ropivacaine with a concentration of 0.33% and 0.25% mixed with 1 μg/kg dexmedetomidine 30 ml for anterior quadratus lumborum block on affected side.Intravenous combined inhalation anesthesia was used.Patients in both groups were treated with PCIA,the formula was tramadol 800 mg with flurbiprofen axetil 100 mg with 0.9% sodium chloride solution 54 ml,PCIA solution totaling 80 ml,no first loading dose and background infusion Dose,set the PCA dose to 2 ml and lock time to 15 min,and the visual analogue score(VAS)was maintained ≤3.If the VAS was≥4,50 mg tramadol was injected intravenously for salvage analgesia.Recorded the remedial analgesia and the number of PCA compressions within 72 hours after the operation;recorded the recovery time of muscle strength grade Ⅱ and Ⅲ,the time of first landing after operation and the length of postoperative hospital stay;recorded the nausea and vomiting,hypotension,and sinus within 72 hours after the operation;recordeded the occurrence of bradycardia,hematoma at the puncture site,and excessive sedation;recorded the patients’ analgesia satisfaction score.Results: Compared with the R1 group,the postoperative grade II and III muscle strength recovery time,the time to get out of bed for the first time and the length of hospitalization in the R2 group were shortened(P<0.05),and there was no significant difference in the number of PCA compressions and the satisfaction score of postoperative analgesia(P>0.05).Both groups did not receive postoperative salvage analgesia,and there were no hematoma at the puncture sites.There was no significant difference in the incidence of postoperative nausea and vomiting,hypotension,sinus bradycardia and excessive sedation in the two groups(P>0.05).Conclusion:Compared with 0.33% ropivacaine,anterior QLB with0.25% ropivacaine mixed with dexmedetomide is more effective for elderly patients with THA.