The Optimization Efficacy Of Dexmedetomidine And Remifentanil Used To Supplement Lumbar Plexus Combined With Sciatic Nerve Block For Hip Arthroplasty In The Elderly Patients

Objectives To evaluate the optimization efficacy of dexmedetomidine and remifentanil used to supplement lumbar plexus combined with sciatic nerve block for hip arthroplasty in the elderly patients.Methods Lumbar plexus combined with sciatic nerve block was performed by ultrasound and nerve stimulator guided in all the 120 patients,scheduled for unilateral hip arthroplasty.Meanwhile,certain dose of dexmedetomidine,remifentanil or the combination of the two agents was used to auxiliary intravenous anesthesia.The patients,were randomly divided into 4 groups(n=30 each): In the group Y,after a loading dose of 0.5ug/kg in 10 min,dexmedetomidine was infused at 0.3ug/kg·h;in addition,remifentanil was infused at 0.05ug/kg·min in the group Ra;and remifentanil at 0.1ug/kg·min in the group Rb as well;besides,in the group YRa,remifentanil was infused at 0.05ug/kg·min,moreover dexmedetomidine was infused at 0.3ug/kg·h after a loading dose of 0.5ug/kg in 10 min.The nerve block was performed in each group at 10 min after intravenous administration,and all the patients were stopped infusion at 10 min before the end of surgery.Then,mean artery pressure(MAP),heart rate(HR),pulse oxygen saturation(Sp O2),respiratory rate(RR),bispectral index(BIS)value,visual analog scale(VAS)scores and the plasma concentration of cortisol(Cor)were regularly recorded after admission to operating room(T0),immediately after the nerve block(T1),at 0,15 and 30 min after the beginning of surgery(T2-T4),and the end of surgery(T5).Results 1 Effect on MAP: In the YRa group,MAP were significantly reduced(P< 0.05)at all time points,except T2,but higher than Rb group(P< 0.05).Moreover,there was no significant difference between group YRa and Y,but the MAP was lower than that in the Y group at T1(P< 0.05).2 Effect on HR: the significant decrease in HR(P< 0.05)was observed in all groups,particularly in group Rb and YRa.In YRa group,HR were lower significantly at each time point,compared with the Y group and Ra group(P < 0.05),in addition to T1 time;but no significant difference with the Rb group.3 Effect on RR: RR were decreased at every time point of each group(P< 0.05).In YRa group,RR were not significantly different,compared with group Ra,at each time point except T2;but significantly lower than that in the Y group(P< 0.05),and higher than that in the Rb group(P< 0.05).4 Effect on Sp O2: the significant decrease was observed at each time point in all groups(P< 0.05).In YRa group,Sp O2 were lower significantly at each time point,compared with group Y(P< 0.05);moreover not significantly different at T1,T2 and T3,compared with group Ra or Rb;but higher than that in the Ra group(P< 0.05),and lower than that in the Rb group(P< 0.05),at T4 and T5.5 Effect on VAS: The VAS scores in the Y and Ra group were decreased at T1,T2 or T5 significantly(P< 0.05);and in the Rb and YRa group at T1-T5 significantly as well(P< 0.05).In YRa group,the VAS scores were not significantly different compared with group Rb,at each time point,but lower than that in the Y and Ra group(P< 0.05).6 Effect on BIS: The significant decrease was observed at each time point in all groups(P< 0.05).The BIS value in group Y and YRa were lower significantly at all the time points,compared with group Ra and Rb(P< 0.05).In YRa group,the BIS value were lower at T1,T2 and T3 significantly(P<0.05),compared with Y group,but not significantly different at T4 and T5.7 Effect on Cor: The significant decrease was observed at each time point in all groups(P< 0.05).In Y group,the plasma concentration of Cor were lower than that of Ra or Rb group at the rest of the time point(P< 0.05),besides there was no significant difference at T2 and T3 compared with group Rb.In YRa group,the plasma concentration of Cor were lower than that of Ra or Rb group at each time point(P< 0.05);and lower compared with Y group(P< 0.05),at other time point except T1.Conclusions Certain dose of dexmedetomidine combined with remifentanil assisting lumbar plexus-sciatic nerve block through intravenous infusion,reduced opioids consumption,which could not only provide better perioperative sedation and analgesia efficacy,but also inhibit the stress response fully,with stable hemodynamics and respiratory.That might be used to hip arthroplasty in elderly patients safely and efficiently.