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Quantitative Evaluation of Aerosol Generation During In-Office Flexible Laryngoscopy

Educational Objective
To identify the key insights or developments described in this article
1 Credit CME
Key Points

Question  Is office flexible laryngoscopy an aerosol-generating procedure?

Findings  In this cohort study of 134 patients, there were no significant changes in aerosol counts identified in patients undergoing flexible laryngoscopy, including when topical nasal spray was applied and regardless of whether the mouth was covered with a mask.

Meaning  Protocols to mitigate risk associated with aerosol-generating procedures are probably not necessary for office flexible laryngoscopy.


Importance  Despite growing scientific knowledge and research, it is still unknown if office flexible laryngoscopy (FL) is aerosol generating and thereby potentially increases the risk of SARS-CoV-2 transmission. The limited literature that exists is conflicting, precluding formal conclusions.

Objective  To determine whether FL is aerosol generating.

Design, Setting, and Participants  This prospective cohort study included 134 patients seen in the otolaryngology clinic at a single tertiary care academic institution between February and May 2021. Two optical particle sizer instruments were used, quantifying particles ranging from 0.02 μm to 5 μm. Measurements were taken every 30 seconds, with sample periods of 15 seconds throughout the patient encounter. Instruments were located 12 inches from the patient’s nares. Timing of events was recorded, including the start and end of physical examination, topical spray administration, start and end of laryngoscopy, and other potential aerosol-generating events (eg, coughing, sneezing). Data analysis was performed from February to May 2021.

Exposures  Office examination and office FL.

Main Outcomes and Measures  Bayesian online change point detection (OCPD) algorithm was used to detect significant change points (CPs) in this time-series data. The primary outcome was significant CP after FL compared with baseline physiologic variations, such as breathing and phonation.

Results  Data were collected from 134 patients between February and May 2021. Ninety-one encounters involved FL. Of this group, 51 patients (56%) wore no mask over their mouth during FL. There was no statistically significant CP in either visits involving FL or visits where FL was not performed. Use of nasal spray did not result in CP in aerosol levels. Overall, neither the number of people present in the examination room, masks over patients’ mouth, the duration of the visit, nor the duration of FL were associated with mean aerosol counts, regardless of the exposure. For larger aerosol sizes (≥1 μm), however, rooms with higher air exchange rates had significantly higher reductions in mean aerosol counts for visits involving FL.

Conclusions and Relevance  The findings of this cohort study support that FL, including topical spray administration, is not a significant aerosol-generating procedure. The Bayesian OCPD model has a promising application for future aerosol studies in otolaryngology.

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Article Information

Accepted for Publication: September 1, 2022.

Published Online: October 27, 2022. doi:10.1001/jamaoto.2022.3316

Corresponding Author: Joseph A. Paydarfar, MD, Section of Otolaryngology, Audiology, & Maxillofacial Surgery, Dartmouth Hitchcock Medical Center, One Medical Center Dr, Lebanon, NH 03766 (joseph.a.paydarfar@hitchcock.org).

Author Contributions: Drs Bastien and Paydarfar had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Bastien, Wiredu, Lee, Hinchcliff, Paydarfar.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: Bastien, Wiredu, Lee, Hinchcliff, Paydarfar.

Critical revision of the manuscript for important intellectual content: Bastien, Wiredu, Rees, Paydarfar.

Statistical analysis: Bastien, Wiredu, Rees.

Administrative, technical, or material support: Bastien, Lee, Paydarfar.

Supervision: Paydarfar.

Conflict of Interest Disclosures: None reported.

Meeting Presentation: This research was presented at the 2021 Fall Voice Conference; October 21-23, 2021; Miami, Florida.

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