A Randomized-controlled Trial to Compare the Effectiveness of 4% Nebulized Lignocaine Versus 10% Lignocaine Spray in Patients Undergoing Flexible Bronchoscopy

Flexible bronchoscopy is common procedure used in the diagnosis and treatment of a variety of tracheobronchial diseases. The bronchoscope can be used to sample material not only from the visualized regions but also from the more distal pulmonary parenchyma. It is a safe outpatient exam that carries little risk. While performing the procedure most of the patients express some fear of pain, difficulty in breathing, nasopharyngeal irritation, and cough. During routine diagnostic flexible bronchoscopy, the most distressing symptom experienced by the patients is a cough, and control of a cough is vital for a successful procedure. Administration of a topical anaesthetic drug to the upper airway, larynx, and tracheobronchial tree can reduce a cough and patient's discomfort. The most commonly used topical anaesthetic agent in bronchoscopy is lignocaine because of its quick onset and short duration of action with decreased toxicity as compared to other agents. There are several ways to achieve topical anaesthesia in flexible bronchoscopy including nebulization, direct spray, by tracheal injection, or via nasal, or "spray as you go" technique through the working channel of the bronchoscope. The use of topical anaesthesia, sedation, and analgesia during flexible bronchoscopy varies according to physicians, institutions and geographic locations in the world. Generally, moderate sedation is used in bronchoscopy in which patients can respond to verbal commands. Deep sedation is less commonly used in which patients cannot be easily aroused but respond to repeated or painful stimulation.

Antoniades et al. demonstrated that topical lidocaine through the bronchoscope significantly decreased cough frequency and the total dose of sedation required during flexible bronchoscopy. In a randomized controlled trial of 54 patients, Keane et al. concluded that nebulized and sprayed lignocaine have similar efficacy as topical anaesthetics in fiberoptic bronchoscopy but patients preferred the nebulized route. Noitasaeng et.al. concluded in their study that spraying lidocaine took less time to start the procedure, with greater ease of instrumentation, less incidence of hypersecretion, less gag reflex, and smooth operation during the procedure but patients preferred nebulized lidocaine administration.

At the investigators' center, it has been a routine practice to perform flexible bronchoscopy without sedation in patients who require only diagnostic flexible bronchoscopy and assessment of airway anatomy and other routine procedures such as endobronchial biopsy or transbronchial biopsy. Previously, the investigators had shown that 1% lignocaine given by spray-as-you-go method was similar in efficacy to 2% lignocaine for topical anesthesia during routine flexible bronchoscopy. However, in this study both the groups received nebulized lignocaine and lignocaine spray prior to flexible bronchoscopy in addition to lignocaine solution ad lib.

The investigators hypothesized that either nebulized lignocaine or lignocaine spray given alone prior to flexible bronchoscopy for inducing topical anesthesia will have similar efficacy compared to the combination of the two agents.