Effect of single dose inhaled lidocaine on the function of lung ventilation in asthmatics

Objective To observe the effect of single dose of inhaled lidocaine on forced expiratory volume at one second (FEV 1) and peak expiratory flow (PEF) in asthmatics with their current medications maintained, thereby discuss whether inhaled lidocaine is likely to serve as a routine treatment.Methods A randomized, double blind, placebo controlled study was performed in 20 asthmatics cases without current flares, medications of all patients were maintained. Each patient received 5ml of normal saline or 100 mg of lidocaine (2%, 5ml) administered as aerosols from a nebulizer. FEV 1 and PEF were determined before inhalation (as baselines) and at 5,10,20,30,45,60 min after nebulization.Results There was a transient fall in mean FEV 1 and mean PEF after the inhalation of both NS and lidocaine; the difference of mean percentage change (%baseline) was not significant between the two treatments 5～10?min after inhalation. The mean (±s) increase of FEV 1 and PEF was as high as (6.2±6.2)% and (5.8±3.8)% 45～60?min following lidocaine, but the increase was slight following normal saline, and difference was significant between the two treatments at 20～60min after inhalation ( P 0.01). About 45% of subjects experienced the increases in FEV 1 and PEF more than 7% of baseline following lidocaine inhalation while few showed such increases following NS inhalation( P 0.01). The incidence of adverse reaction was 15%.Conclusions Inhalation of 100mg lidocaine by nebulizer in asthmatics with their medications maintained caused a transient slihgt fall in FEV 1 and PEF in the majority of the subjects. FEV 1 and PEF showed obvious improvement 20～60 min after inhalation of lidocaine.