Nebulized dexmedetomidine prior to flexible bronchoscopy in reducing procedural cough episodes a randomized double blind clinical trial. (NCT: CTRI/2022/07/044389, NICOBAR group of investigators)

Abstract

Background

Flexible bronchoscopy (FOB) or video bronchoscopy is a day-care procedure indicated in the diagnosis of various pulmonary disorders. FOB is done under conscious sedation with the use of local lignocaine to reduce cough episodes. Nebulized dexmedetomidine has been shown to have local anaesthetic as well as systemic action. This study investigated the role of Nebulized dexmedetomidine delivered prior to FOB to reduce cough episodes.

Methods

It was a double blind, randomized controlled trial conduced on subject undergoing diagnostic FOB. Subjects with recent history of myocardial infarction or cerebrovascular accidents were excluded. Subjects undergoing therapeutic bronchoscopy or endobronchial ultrasound were also excluded. Subjects in intervention arm received Nebulized dexmedetomidine at a dose of 2 μg/kg whereas control arm subjects were nebulized with normal saline. Primary outcome of the study was to compare the proportion of subjects with moderate-to-severe cough among the two groups.

Results

Over a period of 6 months, 128 cases were screened and 100 were randomized in a ratio of 1:1. Mean age of study population was 49.5 ± 15.6 years with majority being males (64%). Baseline characteristics were similar in the two groups. A higher number of cases in Nebulized dexmedetomidine arm underwent bronchoalveolar lavage (50% versus 24%) whereas a higher number of subjects in control groups underwent “bronchoscopy for airway inspection” (42% versus 20%). The difference in the proportion of subjects with moderate to severe cough in the two groups was not statistically significant (22% versus 18% in Nebulized dexmedetomidine group and control group, respectively, p > 0.05). Doses of anaesthetic drugs (fentanyl, midazolam, locally instilled lignocaine) were also similar in the two groups. However, the discomfort level experienced by the patient as well as ease of doing procedure for the operator, as measure by VAS score, were significantly lower in the intervention arm as compared to the control arm (51 ± 20.6 versus 72.2 ± 13.1, for patient reported discomfort and 12.5 ± 9.8 versus 36.6 ± 27.2, for operator ease of doing procedure). Mean Richmond Agitation Sedation Scale score was significantly lower in the Nebulized dexmedetomidine arm (−0.22 ± 0.1 versus 0.12 ± 0.1). Dexmedetomidine as well as normal saline were equally well tolerated in nebulized form. None of the study subjects reported any intervention related adverse events.

Conclusion

This study demonstrated that Nebulized dexmedetomidine has insignificant topical action to reduce cough episodes as compared to normal saline in diagnostic FOB, but systemic effects remain to be investigated.