Dexmedetomidine as an adjuvant for Hypotensive Anaesthesia during Functional Endoscopic Sinus Surgery (FESS)

Abstract

Introduction:FESS (Functional Endoscopic Sinus Surgery) is done via endoscope and the area is highly vascular thus it becomes important to minimize bleeding. Hence we require hypotensive anesthesia. Various drugs have been used for the purpose: nitroglycerine (NTG), sodium nitroprusside(SNP),propofol,beta blockers, calcium channel blockers, higher concentrations of inhalational anesthetics etc. Since all these drugs have certain limitations there was a search for safer and more effective drug .Dexmedetomidine, a newer alphaadrenoceptor agonist,fulfills this requirement since it is short acting, has no residual effects, produces sedation and analgesia and reduces mean arterial pressure thereby reducing intraoperative blood loss. Aims: To study the efficacy of dexmedetomidine in providing hypotensive anaesthesia so as to minimize bleeding during endoscopic sinus surgery in a randomized double blind control study. Method:40 patients of ASA grade I/II, aged18-55yrs,scheduled for endoscopic sinus surgery, were randomly allocated into two groups of twenty each by sealed envelope method. Group C: received Normal saline as loading dose of 1mcg/kg intravenously followed by maintenance infusion of 0.6mcg/kg intravenously, Group D: received dexmedetomidine in similar doses. The loading dose was given slowly over 15 minutes. The surgery was started after the loading dose was over. Both the anaesthetist conducting the study and the patient were blinded to the study drug. The amount of blood loss, doses of intravenous& inhalation agents and side effects were studied. Results:The patient characteristics did not differ in bothcontrol(C) and study (D) groups (Table1). Blood losses were lower in group D as compared to group C (p = 0.03).Total dose of fentanyl (p< 0.001),propofol( p <0.001 )and isoflurane ( p =0.04 )were lower in group D as compared to group C. The VAS scores in the immediate postoperative periods were also lower in the group D (p =0.03).The only side effect noted was bradycardia (2patients)which however reverted with discontinuation of the drug.Atropine was not required. Conclusions:Dexmedetomidine is a safe &effective adjuvant for hypotensive anaesthesia to decrease bleeding and thus provide bloodless field during FESS surgery. It also decreases the dose requirements of