A study on factors determining dose of topical lignocaine during broncho-alveolar lavage by spray-as-you-go technique: A single centre observational study.

ABSTRACT: Basic bronchoscopic diagnostic procedures like Broncho-alveolar lavage (BAL) are often performed without sedation, using lignocaine administered via the working channel of bronchoscope (spray-as-you-go technique) and other routes. Our aim was to evaluate the factors responsible for variation in the total dose of lignocaine administered in individual subjects. We prospectively included consecutive subjects undergoing BAL in an outpatient setting from August 2016 to November 2017 at our centre. The subjects were administered lignocaine via nebulization, nasal gel, oropharyngeal spray before and during bronchoscopy ("spray-as-you-go") as per a predefined protocol. The demographic details, high resolution computerized tomography (HRCT) characteristics, procedural details, doses of lignocaine administered and a visual analogue scale (VAS) for satisfaction with the procedure were recorded. Using lignocaine dose as outcome, variables were assessed for effect by univariate and multivariate regression analysis. 96 subjects were included with a mean age of 40 years and male predominance (60.4%). Cough was the most common presenting symptom (64.6%). Predisposing factors included tuberculosis (47.9%) and smoking (23.2%). Maximum variation in lignocaine dose occurred prior to intubating vocal cords using "spray-as-you-go", which was significantly related to history of past tuberculosis ( p = 0.031), obstructive airway disease ( p = 0.009), fibrotic sequelae ( p = 0.011) and bronchiectasis ( p = 0.049). Obstructive airway disease and fibrotic sequelae were also significant on multivariate analysis ( p = 0.01 and 0.005 respectively). Obstructive airway disease and architectural distortion due to fibrotic sequelae leads to higher dose requirement for lignocaine during BAL by fibreoptic bronchoscopy. Caution must be maintained during bronchoscopic procedures to avoid exceeding recommended maximum doses in such patients. Key Words: Bronchoscopy, broncho-alveolar lavage, lignocaine dose Full Text: PDF(504KB