Effects of lignocaine on pressor response to laryngoscopy and endotracheal intubation during general anaesthesia in rigid suspension laryngoscopy.

OBJECTIVE: This study aimed to compare the effects of topical and systemic lignocaine on the circulatory response to direct laryngoscopy performed under general anaesthesia.

METHODS: Ninety-nine patients over 20 years of age, with a physical status of I-II (classified according to the American Society of Anesthesiologists), were randomly allocated to 3 groups. One group received 5 ml of 0.9 per cent physiological saline intravenously, one group received 1.5 mg/kg lignocaine intravenously, and another group received seven puffs of 10 per cent lignocaine aerosol applied topically to the airway. Mean arterial pressures, heart rates and peripheral oxygen saturations were recorded, and changes in mean arterial pressure and heart rate ratios were calculated.

RESULTS: Changes in the ratios of mean arterial pressure and heart rate were greater in the saline physiological group than the other groups at 1 minute after intubation. Changes in the ratios of mean arterial pressure (at the same time point) were greater in the topical lignocaine group than in the intravenous lignocaine group, but this finding was not statistically significant.

CONCLUSION: Lignocaine limited the haemodynamic responses to laryngoscopy and endotracheal intubation during general anaesthesia in rigid suspension laryngoscopy.