Effect of lignocaine pre-treatment on conditions for airway assessment under direct laryngoscopy following intravenous propofol: a randomised, double-blind study

Rajiv Singhal¹, U.K Shenoy²

¹Liverpool Hospital, Liverpool, NSW, Australia
²Kasturba Medical College, Manipal, India

Background: In recognised difficult airway situations, propofol can be useful for airway assessment under direct laryngoscopy without or prior to the use of muscle relaxants as it depresses airway reflexes and is short acting. An intravenous lignocaine bolus preceding propofol can have an additive effect on depression of airway reflexes and in attenuating hemodynamic response to laryngoscopy

Methods: Sixty patients were allocated to two groups - propofol (P) or lignocaine-propofol (LP) by random picking of lots. Group P patients received a bolus of 0.9% saline and Group LP patients received lignocaine 1.5 mg.kg-1 followed immediately by injection of 1% propofol 2.0 mg.kg-1 over thirty seconds. Sixty seconds after a full-calculated dose of propofol was injected, the laryngoscopy conditions were assessed. Hemodynamic parameters and episode/s of apnoea were also recorded

Results: As the table shows, seven patients in propofol group had unsatisfactory airway assessment conditions versus none in the Lignocaine-Propofol group. Higher incidence of apnoea was observed in Group LP but none of the patients in either group had significant arterial desaturation, laryngospasm or had any recall of post induction events.

Conclusion: Pre-treatment with intravenous lignocaine (1.5 mg.kg-1) in the anaesthetic induction sequence using propofol (2 mg.kg-1) improves the conditions for laryngoscopic assessment of airway

References:

1. Erhan E, Ugur G, Gunusen I, Alper I, Ozyar B; 2003
2. Collins L, Prentice J, Vaghadia H; 2000