Clonidine, an α2 agonist, has been used in anesthesia for many years to provide sedation, anxiolysis, analgesia, controlled hypotension, and to provide opioid-sparing anesthesia. Recently, there has been a great interest in using the newer α2 agonist, dexmedetomidine, because of its more selectivity toward α2 adrenoreceptors. We compared the effects of clonidine with dexmedetomidine on anesthetic requirement and recovery from anesthesia.Methods:
Seventy-four patients undergoing major spine surgery were randomly allocated to receive either oral clonidine premedication followed by an intraoperative saline infusion (group A) or placebo premedication followed by dexmedetomidine infusion in the intraoperative period (group B). Standard anesthesia protocols were followed for induction and maintenance. Heart rate, blood pressure, and end-tidal concentrations of isoflurane were noted every 15 minutes after proning. Hypertensive responses were treated with bolus doses of propofol and fentanyl. Hypotensive episodes were treated with bolus doses of ephedrine or phenylephrine. Primary outcomes were the comparisons of the effect of these 2 drugs on anesthetic requirement and recovery from anesthesia. Secondary outcomes were the comparisons of the hemodynamic response, intraoperative analgesic requirement, and blood loss during surgery.Results:
Demographic data, duration of surgery, total dose of fentanyl and propofol requirement, blood loss, and the recovery time were comparable between the 2 groups. Both drugs reduced the isoflurane requirement during surgery. However, the reduction was more and statistically significant with dexmedetomidine compared with clonidine group at 1 and 2 hours after proning (P=0.001, 0.039 at 1 and 2 h). Both drugs are equally effective in controlling the hemodynamics, and the number of episodes of hypotension, hypertension, and bradycardia were comparable between the 2 groups.Conclusions:
Both clonidine and dexmedetomidine have anesthetic-sparing effect; however, it was more with dexmedetomidine than with clonidine. Recovery from isoflurane anesthesia was similar between both groups. Both are equally effective in controlling the hemodynamic response and reducing the blood loss during spine surgery.