A randomized controlled trial on comparison of sevoflurane induction to propofol induction for insertion of laryngeal mask airway in adults

Background: The laryngeal mask airway is a popular supraglottic airway device, with intravenous propofol being the agent of choice for its insertion. Sevoflurane is a volatile anaesthetic agent, which combines rapid, smooth inhalational induction of anaesthesia with rapid recovery, making it ideal for day care anaesthesia. Objective: To compare conditions for LMA insertion following induction with intravenous propofol and inhalational induction with sevoflurane (viz., jaw opening, ease of insertion, coughing, gagging, laryngospasm and patient movement) and number of attempts for insertion of Laryngeal Mask Airway. Study design: A randomized single blinded clinical trial. Methods: After obtaining the institutional ethical committee approval, fifty adults patients were allocated randomly into two groups of 25 each; group P (Propofol group) and group S (Sevoflurane group). Patients in group P were induced with 2.5 mg/kg intravenous Propofol. In group S, after priming the Bain’s circuit with Sevoflurane 8% in 50% N2O and O2 (flow rate – 8 litre/minute) for 30 seconds, patients were asked to take vital capacity breaths via the face mask connected to primed circuit. The LMA insertion was attempted afterloss of eyelash reflex and assessing the jaw relaxation. Scoring system was used to grade the conditions for the LMA insertion. Results: The mean time required for induction with propofol was 34.08 secs and with sevoflurane it was 46.96 secs. The mean time required for LMA insertion with propofol was 63.04±3.75ssecs and in sevoflurane group it was 87.48±15.14ssecs. In both the groups excellent conditions for LMA insertion were obtained. Complications while inserting LMA were not significant in both the groups. Conclusion: The observation of this study shows that propofol produces a much faster induction and good jaw relaxation for insertion of LMA than induction with sevoflurane. The insertional characteristics like coughing, gagging, laryngospasm, ease of insertion,