A comparative evaluation of use of dexmedetomidine versus fentanyl for anesthesia induction with propofol for insertion of laryngeal mask airway

Background: Airway management is one of the prime concerns for anesthesiologists. Dr Archibald Brain invented a supraglottic airway device - "Laryngeal Mask Airway" (LMA) which keeps a patient's airway open during anesthesia. When propofol is used along with either fentanyl or dexmedetomidine, it provides stable cardiorespiratory condition, diminished airway reflexes and smooth insertion of LMA. Aim: Aim of this study is to compare the hemodynamic and respiratory parameters, apnea time and patient's response to LMA insertion between dexmedetomidine-propofol and fentanyl-propofol combinations as a primary outcome. Secondary outcome is to observe any side effect in intraoperative and postoperative period associated with the study drugs. Methodology: Prospective, double blind, randomized clinical study in 140 healthy patients of both sex, having ASA grade I and II was carried out. Patients were demographically similar. Patients were randomized to receive either intravenous (i.v.) dexmedetomidine(1 mu g/kg) -propofol(2mg/kg) injections- Group D (n = 70) or i.v. fentanyl(1 mu g/kg)-Propofol(2mg/kg) injections- Group F (n = 70) for LMA insertion. Parameters like heart rate(HR), respiratory rate (RR), systolic blood pressure(SBP), diastolic blood pressure(DBP), mean arterial blood pressure(MAP), oxygen saturation(SpO2) were recorded before induction, 30 seconds after induction, 1, 3, 5, 10, 15, 30, 45 and 60 minutes (min.) after insertion of LMA. Apnea time was noted. Patient's responses to LMA insertion such as jaw mobility, coughing, gagging or any movement were noted. Other side effects were also observed. Results: In Group-D HR, SBP, DBP and MAP showed significant decrease throughout the study period following LMA insertion, while in Group-F there was rise in the above parameters noted immediately after LMA insertion. In Group-D spontaneous respiration was well preserved and apnea time was significantly shorter compared to Group-F. LMA insertion conditions were acceptable in patients with both the Groups. Incidence of bradycardia and hypotension was higher in the patients of Group-D while incidence of nausea and vomiting was present in two patients of Group-F. Conclusion: Dexmedetomidine 1 mu g/kg with propofol 2mg/kg i.v. provides beneficial effect in attenuation of hemodynamic response to LMA insertion, better preservation of spontaneous respiration and acceptable LMA insertion conditions as compared to fentanyl 1 mu g/kg with propofol 2mg/kg i.v. without major side effects.