Effect Of Epidural Injection Of Subthreshold Dose Of S(+)-Ketamine On Combined Spinal-epidural Block In Elderly Patients Undergoing Hip Arthroplasty

ObjectiveTo explore the effect of subthreshold dose s(+)ketamine on combined spinal epidural block in elderly patients undergoing hip arthroplasty.MethodsNinety elderly patients with ASA Ⅱ-Ⅲ were randomly divided into three groups,30 cases in each group.After subarachnoid administration,group a received 0.1mg/kg s(+)ketamine 5ml in epidural space through epidural catheter.Group B was injected with 0.2mg/kg s(+)ketamine 5ml while group C was injected with 5ml normal saline.Systolic blood pressure(SBP),diastolic blood pressure(DBP),mean arterial pressure(MAP),heart rate and other hemodynamic indexes were observed and recorded when the patients of three groups entered the operating room(TO),anesthesia block completion(T1),skin incision(T2),at the end of the operation(T4).At the same time,the completion time of anesthesia block,anesthesia duration,adverse reactions,and VAS scores were recorded at 2h,6h,12h,24h after the surgery.ResultsTO:No significant difference of the SBP,DBP,MAP,and HR could be observed among the three groups(P>0.05).T1:The SBP of the three groups had significant difference(P<0.05),of which no significant difference was shown between group A and group B(P>0.05)whereas group C was lower than that of group A(P>0.05);The DBP of group C was significantly lower than that of group A(P<0.05);The MAP of group B and group C was lower than that of group A(P<0.05),but there was no significant difference between group B and group C(P>0.05);The HR of group C was lower than that of group A and group B(P<0.05).T2:The SBP of group B and C was significantly lower than that of group A(P<0.05),whereas there was no significant difference between group A and group B(P>0.05),as well as group B and group C(P>0.05);The DBP of group C was lower than that of group B(P<0.05);The MAP of group C was lower than that of group A and group B(P<0.05);The HR of group C was lower than that of group A and group B(P<0.05),but no significant difference was observed between group A and group B(P>0.05).T3:The SBP of group B was significantly lower than that of group A and group C(P<0.05),nevertheless,there was no significant difference between group A and group C(P>0.05);The DBP and map of three groups had no significant difference(P>0.05);The HR of group C was lower than that of group B(P<0.05),but there was no significant difference between group A and group C(P>0.05).There was no significant difference in the time of complete block among the three groups(P>0.05).The duration of block was statistically significant(P<0.05).The duration of block in group A and group B was significantly longer than that in group C(P<0.05),but there was no significant difference between group A and group B(P>0.05).The result showed that significant differences existed in VAS scores among the three groups at 2h,6h,12h and 24h(P<0.05).At the same time,the scores of group A and group B were significantly different at these four time points,while the score of group B was lower(P<0.05).There was no significant difference in the adverse reactions of intraoperative and postoperative among the three groups(P>0.05).ConclusionEpidural injection of subthreshold dose of S(+)ketamine can maintain the hemodynamics relatively stable after anesthesia,and significantly prolong the time of subarachnoid block with ropivacaine.What’s more,It is also able to reduce the VAS score,and improve the early postoperative analgesic effect without increasing the incidence of adverse reactions.