Background: The optimal concentration of lignocaine to be used during flexible bronchoscopy (FB) remains unknown. This randomized controlled trial compared the efficacy and safety of 1% and 2% lignocaine solution for topical anesthesia during FB.
Methods: Consecutive patients were randomized to receive either 1% or 2% lignocaine solution through the bronchoscope by the "spray-as-you-go" technique. The primary outcome of the study was the assessment of cough by the operator and the patient using the visual analog scale (VAS) and pain assessment using the faces pain rating scale. The secondary outcomes included total lignocaine dose, oxygenation status, adverse reactions related to lignocaine, and others.
Results: Five hundred patients were randomized (median age, 51 years; 71% men) 1:1 to either group. The median operator VAS score for cough was significantly higher (25 vs 21, P = .015) in the 1% group; however, the patient VAS score was not significantly different (32 vs 27, P = .065). The pain rating was similar between the two groups. The median cumulative dose of lignocaine was significantly higher in the 2% group (397 mg vs 312 mg, P = .0001; 7.1 mg/kg vs 5.7 mg/kg, P = .0001). About 28% of patients in the 2% group exceeded the maximum recommended dose (> 8.2 mg/kg) of lignocaine. No adverse event related to lignocaine overdose was seen in either group.
Conclusions: One percent lignocaine was found to be as effective as 2% solution for topical anesthesia during FB, albeit at a significantly lower dose as the latter. Thus, 1% lignocaine should be the preferred concentration for topical anesthesia during FB.
Trial registry: ClinicalTrials.gov; No.: NCT01955824; URL: www.clinicaltrials.gov.