Randomized Double-Blind Comparison of Ketamine-Propofol and Fentanyl-Propofol for the Insertion of Laryngeal Mask Airway in Children

BACKGROUND: Till date, different combinations of adjuncts with induction agents have been tried for Laryngeal Mask Airway (LMA) insertion; yet, the ideal combination that provides the best insertion conditions with minimal side effects has not been identified, particularly in children. PATIENTS & METHODS: Hundred paediatric ASA grade I and II patients, aged 3-12 years, were randomly allocated to receive intravenously either fentanyl 2μg kg(-1) (Group F, n=50) or ketamine 0.5 mg kg(-1) (Group K, n=50), before induction of anaesthesia with propofol 3.5 mg kg(-1). Arterial blood pressure and heart rate were measured before induction (baseline), immediately before induction, immediately before LMA insertion, and at 1, 3 and 5 minutes after LMA insertion. Following LMA insertion, the following six subjective endpoints were graded by a blinded anaesthetist using ordinal scales graded 1 to 3: mouth opening, gagging, swallowing, head and limb movements, laryngospasm and resistance to insertion. Duration and incidence of apnoea was also recorded. RESULTS: The incidence of resistance to mouth opening, resistance to LMA insertion and incidence of swallowing was not statistically significant between the two groups. Coughing/ gagging was seen in 8% patients in group K as compared to 28% patients in group K. Limb/ head movements were observed in 64% patients in the fentanyl group and in 76% patients in the ketamine group. Laryngospasm was not seen in any patient in either group. Incidence of apnoea was 80% in the fentanyl group and 50% in the ketamine group. The heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure were consistently higher in the ketamine group as compared to the fentanyl group. CONCLUSION: The combination of fentanyl (2μg kg-1) and propofol (3.5mg kg-1) provides better conditions for LMA insertion in children than a combination of ketamine (0.5 mg kg-1) and propofol (3.5mg kg-1).