Effectiveness of Fentanyl, Dexmedetomidine and Lignocaine for Tolerance to Laryngeal Mask Airway Insertion with Propofol Induction: A Randomised, Comparative, Double-blinded Trial

Background and Aims: Several drugs, such as opioid, lignocaine, ketamine, dexmedetomidine and midazolam, have been used as adjuvants with propofol induction to achieve optimal laryngeal mask airway (LMA) insertion conditions and to decrease the requirement of propofol. This study has been undertaken to compare the effectiveness of intravenous (IV) fentanyl, IV dexmedetomidine and topical lignocaine, before propofol induction to achieve optimal conditions for LMA insertion. Methodology: This randomised, double-blinded, comparative clinical study included 147 American Society of Anesthesiologists I–II patients aged between 16 and 60 years undergoing elective surgery under general anaesthesia. Patients were divided into three groups: Group F (IV fentanyl 2 μg/kg), Group D (IV dexmedetomidine 0.5 μg/kg) and Group L (2 ml of topical 2% lignocaine through atomiser) before induction. All patients received propofol 2 mg/kg for induction. The Muzi et al .’s scoring system was used to assess jaw relaxation and suppression of airway reflexes. Other outcomes assessed were haemodynamic changes, adverse events and postoperative airway complications. Results: The Muzi et al .’s scores across the three groups were comparable. The P values for jaw mobility scores <2 and Coughing movement score were 0.085 ( X 2 = 4.94) and 0.270 ( X 2 = 2.61), respectively. The occurrence of breath-holding decreased significantly in Group L ( X 2 = 15.98, P < 0.001). Bradycardia was exclusively noted in Group D ( X 2 = 21.46, P < 0.001). The supplementary dose of propofol was predominantly higher in Group L ( X 2 = 6.10, P = 0.047). Conclusion: All three study drugs were equally effective as an adjuvant with propofol for jaw relaxation and suppression of airway reflexes. While fentanyl has a tendency to cause apnoea and breath-holding, dexmedetomidine was associated with a greater decline in mean arterial pressure and heart rate, and requirements of additional propofol boluses were noticed with topical lignocaine.