Effect Of Different Dose Of Dexmedetomidine For Preventing Of Visceral Traction Reactionduring Caesarean Section Under Spinal Anesthesia

Objectives The aim of this study was to investigate the optimum dose of intravenous singledose dexmedetomidine for preventing of traction reaction in cesarean section under spinal anesthesia.Methods Two hundred ASA physical status I-II patients,full-term primiparas scheduled for elective cesarean section were enrolled in this randomised,placebo-controlled study.Patients were randomly allocated to receive dexmedetomidine in four groups: group C(0.9% normal saline),group D0.6(dexmedetomidine 0.6?g/kg),group D0.8(dexmedetomidine 0.8?g/kg),group D1.0(dexmedetomidine 1.0?g/kg),50 cases in each group.Two minutes after the break umbilical,groups D0.6?D0.8?D1.0were received an intravenous infusion single-dose of 0.6,0.8,1.0ug/kg dexmedetomidine respectively,time was set for 10 minutes.Group C was injected with the same dose of saline.Observe and record maternal blood pressure(BP),heart rate(HR),Ramsay scores,visceral tractive reaction conditions at three points:before iv(T0),10 min after iv(T1and exploration cleaning abdominal(T2).Observe and record patients' sleep time,duration of sedation,intraoperative hypertension,hypotension,chills and the occurrence of nausea and vomiting.The time of first rescue analgesia,cumulated pressing numbers and effective pressing numbers in 24 h after surgry were recorded.Results To the inhibition of visceral traction pain,D0.8 and D1.0groups were obviously better than the D0.6 group and C group,and there was no statistically significant difference between D0.8and D1.0 groups in the T2 period.The functions of slowing down heart rate and increasing blood pressure were weaker In group D0.8 than that in group D1.0 at time T2.Ramsay scores were higher in D0.8 and D1.0groups than in D0.6and C groups.and there was no significant difference between D0.8 and D1.0 groups at time T2.Compared with D0.6 group,the sleep time of D0.8 group and D1.0group was significantly shortened,the difference was statistically significant difference(P<0.05),and the difference between D0.8 group and D1.0 group was no statistically significant difference(P>0.05).Duration of sedation: D0.8 group was significantly longer than D0.6 group,the difference was statistically significant difference(P<0.05),and D1.0 group was longer in D0.8 group,the difference was statistically significant difference(P<0.05).Compared with the first 24 hour analgesic condition in each group,the time of first rescue analgesia in the control group was significantly longer than that in the control group,D0.8 group was longer in D0.6 group.while there was no statistically significantdifference between D0.8and D1.0groups(P>0.05).Cumulative PCIA compressions and effective compressions were compared between groups: the number of PCIA compressions in the D0.6 group was less than that in group C,and the difference was statistically significant(P<0.05).The cumulative PCIA compressions and effective compressions of D0.8 group were less than that of D0.6 group,and the difference was statistically significant(P<0.05).There was no statistical difference between D0.8 and D1.0group(P>0.05).Comparison of adverse reactions in each group: compared with group C and D0.6group,there was no significant difference in bradycardia and hypotension in D0.8group(P> 0.05).The incidence of bradycardia and hypotension in D1.0 group was increased(P<0.05).There was no significant difference in the incidence of hypertension between group C,D0.6 group and D1.0 group(P>0.05).Compared with D0.8 group,the incidence of hypertension was higher.In D0.8 and D1.0 group,the incidence of chills was lower than that of D0.6group and group C(P<0.05),while D0.8 and D1.0 group showed no significant difference.Conclusions Admimistration of dexmedetomidine with the loading of 0.8 ug/kg and 1.0 ug/kg both could alleviate the visceral tractive reaction in cesarean section under spinal anesthesia,Which can effectively restrain intraoperative pull reaction,reduce the incidence of intraoperative chills,and can enhance the postoperative analgesia effect,but the dose of 0.8ug/kg had little effect on maternal hemodynamics.So it is the most suitable dose in cesarean section under spinal anesthesia.