A Randomized, Double-blind, Placebo-controlled Trial to Compare the Effectiveness of Nebulized Anticholinergics for Cough Suppression During Flexible Bronchoscopy

Bronchoscopy is a minimally invasive endoscopic technique for direct visualization of airways, with diagnostic and therapeutic intent. In 1897, Killian laid the foundation of bronchoscopy by extracting an animal bone from the right main bronchus of a farmer using rigid esophagoscope. In 1966, Shigeto Ikeda developed a prototype of flexible bronchoscope. Since its inception, flexible bronchoscope has undergone advancements in design and technology. The technological advancements in the recent decades have improved diagnostic yield and safety, with low morbidity and mortality. Unfortunately, the occurrence of cough during flexible bronchoscopy makes the procedure difficult and increases procedure time with patient discomfort.

Owing to the lack of clinical benefits and possible hemodynamic changes, the British Thoracic Society and Joint Indian Chest Society recommend not to use anticholinergic premedication via the parenteral route for preventing cough before bronchoscopy.

bronchoscopy. A few studies have evaluated inhaled anticholinergic premedication. Inoue et al. (in 1994) studied the effects of inhaled ipratropium bromide on bronchoconstriction in 29 subjects underwent for diagnostic bronchoscopy. They concluded that ipratropium protects against the deleterious effects resulting from topical lidocaine anesthesia during bronchoscopy. Wang et al. evaluated the efficacy of ipratropium bromide in 250 patients in a placebo-controlled trial. They reported that nebulized ipratropium bromide could reduce airway secretions and patient discomfort.

To our knowledge, no study has examined the role of inhaled glycopyrrolate on mucus secretion. We hypothesize that nebulized glycopyrrolate will improve bronchoscopy procedure by effectively suppressing airway mucus secretion, thereby decreasing cough, and thus improving patient comfort during bronchoscopy.

In this study, we aim to compare the efficacy of nebulized glycopyrrolate versus nebulized ipratropium in suppression of cough during flexible bronchoscopy.