Effect Of Dexmedetomidine Combined With Low Concentration Ropivacaine On Rapid Postoperative Rehabilitation Of TKA Patients After Continuous Femoral Nerve Block

Objective To investigate the effects of dexmedetomidine combined with low concentration of ropivacaine for continuous femoral nerve block(CFNB)on postoperative analgesia of TKA and rapid postoperative recovery.Methods From June 2016 to June 2017 ninety patients undergoing primary total knee replacement surgery in patients with choice,male 29 and female 61,aged 52～85 years old,ASA Ⅰ～Ⅲ,were assigned into three groups randomly:dexmedetomidine+ 0.1%ropivacaine group(group DF1),0.1%ropivacaine group(group F1),0.2%ropivacaine group(group F2).All patients were received with combined spinal epidural anesthesia,and accepted surgery by the same group of doctors.Postoperatively femoral nerve block was guided by ultrasound and nerve stimulator.All patients were received self-controlled analgesia continuously connected device.The device drug formula:group DF1 the mixed solution of 0.1%Ropivacaine and lug/ml dexmedetomidine,group F1 0.1%ropivacaine and group F2 0.2%ropivacaine,the capacity is 200 ml,the parameters set as background dose 5 ml/h,a bolus dose of 5 ml/time,with a 60 min lockout interval,lasted for 48 hours.The VAS score of resting,passive femoral movement and muscle strength of quadriceps femoris were recorded at the different time points in the whole postoperative period.Sleep quality class of patients were recorded in the postoperative period.Patients of three groups were recorded with postoperative nausea and vomiting(PONV),postoperative cognitive dysfunction(POCD),bradycardia,the incidence of respiratory depression,the times of PCA pressing,pethidine using,satisfaction degree of analgesia and the length of hospital stay.Results There was no significant difference on general clinical data and intraoperative condition in the three groups(P>0.05).Compared with group F1,group DF1 and group F2 VAS scores were lower in the rest and exercise at the same time.But between group DF1 and group F2 there was no statistically significant difference(P<0.05);comparison in unit quadriceps femoris muscle,group DF1 and group F1,the femoral muscle strength score in four at each time point were higher than those in group F2,group DF1 and group F1 strength score difference was smaller,and not statistically significant(P>0.05);the different time points of group DF1 were longer than the F1 group and group F2 in the maximum walking distance,and the difference was statistically significant(P<0.05).No patients had severe bradycardia,respiratory depression.1 case(3.3%)of nausea and vomiting and 1 case(3.3%)of postoperative cognitive dysfunction occurred in the group DF1.These were significantly lower than F1 group 8 cases(26.7%)and 7 cases(23.3%)(P<0.05);compared to the group F2 of 2 cases(6.7%)and 1 case(3.3%),there was no significant difference between DF1 and F2(P>0.05).The average PCA pressing times of group F1 after operation was higher than the other two groups(P<0.05).9 patients of group F1 had used additional pethidine,more than the other two groups(P<0.05).Compared with F1 group and F2 group,the average sleep quality grade and analgesic satisfaction of group DF1 were increased.The average length of stay in hospital of DF1 was shorter than that group F1 and group F2(P<0.05).Conclusion Dexmedetomidine combined with 0.1%ropivacaine for continuous femoral nerve block after total knee arthroplasty can provide better analgesia effect than 0.I%ropivacaine and less effect of quadriceps femoris than 0.2%ropivacaine.It can promote the early functional exercise of joint in the patients and reduce the incidence of postoperative adverse reactions.It can also improve the hospitalized patients’ satisfaction and shorten the length of postoperative hospital stay,which benefits rapid postoperative recovery after TKA.