The influence of epidural dexmedetomidine and clonidine on ropivacaine epidural anesthesia

Abstract

Objective The aim of this study was to evaluate the efficacy of epidural dexmedetomidine (Dex) and clonidine on ropivacaine epidural anesthesia.Methods Seventy-five patients ASA Ⅰ or Ⅱ,aged 55 y-65 y,scheduled for elective vaginal hysterectomy under epidural anesthesia with ropivacaine were randomly allocated into three groups:patients in group RD were administered 15 ml of 0.75％ epidural ropivacaine and 100 μg of Dex,while group RC received admixture of 15 ml of 0.75％ropivacaine and 100 μg of clonidine,and group C received 15 ml of 0.75％ ropivacaine and saline.Results The patient in group RD exhibited an earlier onset of sensory analgesia at T10 [(8.5±2.4) min] as compared to group RC and group C [(10.4±3.4) min and (12.7±4.3) min].Dex not only provided a higher dermatomal spread but also helped in achieving the maximum sensory anaesthetic level in a shorter period [(13±4) min compared to clonidine (15±4) min and (18±4) min].Bromage scale 3 was achieved earlier in group RD [(18±5) min] than in group RC and group C [(21±4) min and (24±4) min,P＜0.05].Less tramadol consumed in group RD [(87±17) mg] than that in group RC and in group C [(101±21) min and (146±19) mg,P＜0.01] for postoperative analgesia of 24 h(P＜0.05).Sedation scores in group RD and group RC were better than in group C(P＜0.05).The incidence of shivering was lower in group RD and group RC than that in group C (P＜0.05).Respiratory depression was not observed in each group.Conclusions Epidural Dex may reinforce the effect of epidural anaesthesia with ropivacaine and analgesia.Dex is a better neuraxial adjuvant compared to clonidine for providing early onset of sensory analgesia,stable cardio-respiratory parameters and a prolonged post-operative analgesia. Key words: Dexmedetomidine; Clonidine; Epidural anaesthesia; Ropivacaine