The Laboratory Characterization of Fugitive Aerosol Emissions From a Standard Jet Nebulizer With and Without a Filtered Mouthpiece

Manhar Dhanak; Siddhartha Verma; Patrick G Hughes; Ai Ling Ching; Arthur Lo; Candice Clay; Adriana McKinney; John Frankenfield

doi:10.7759/cureus.50611

The Laboratory Characterization of Fugitive Aerosol Emissions From a Standard Jet Nebulizer With and Without a Filtered Mouthpiece

Cureus. 2023 Dec 15;15(12):e50611. doi: 10.7759/cureus.50611. eCollection 2023 Dec.

Authors

Manhar Dhanak¹, Siddhartha Verma¹, Patrick G Hughes², Ai Ling Ching³, Arthur Lo³, Candice Clay³, Adriana McKinney¹, John Frankenfield¹

Affiliations

¹ Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, USA.
² Emergency Medicine, Florida Atlantic University, Boca Raton, USA.
³ Medical Affairs, Theravance Biopharma US, Inc., South San Francisco, USA.

Abstract

Background and objective The risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission from patients with coronavirus disease 2019 (COVID-19) during nebulization is unclear. In this study, we aimed to address this issue. Methods Fugitive emissions of aerosolized saline during nebulization were observed using a standard jet nebulizer fitted with unfiltered and filtered mouthpieces connected via a mannequin to a breathing simulator. Fugitive emissions were observed by using a laser sheet and captured on high-definition video, and they were measured by using optical particle counters positioned where a potential caregiver may be administering nebulization and three other locations in the sagittal plane at various distances downstream of the mannequin. Results The use of a standard unfiltered mouthpiece resulted in significant emission of fugitive aerosols ahead of and above the mannequin (spread over 2 m in front). A mouthpiece with a filter-adaptor effectively suppressed the emissions, with only minor leakage from the nebulizer cup. Particle count measurements supported the visual observations, providing total particle count levels and aerosol concentration levels at the measurement locations. The levels decayed slowly with downstream distance. Conclusions The visualization described above captured the dispersion of emitted aerosols in the plane of the laser sheet, aligned with the sagittal plane. The particle count measurements provided temporal and spatial distributions of the aerosol concentration levels over the time and locations considered. However, the exhaled air and aerosolized droplets spread three-dimensionally in front of and above the mannequin. The results visually highlight the effectiveness of using a filtered mouthpiece in suppressing the fugitive aerosols and identify an approach for limiting the occupational exposure of healthcare workers to these emissions while administering nebulized therapies.

Keywords: aerosol-generating procedures; covid-19; healthcare worker safety; medical aerosols; mouthpiece filter; simulation.

Grants and funding

The study was funded by Theravance Biopharma Ireland Limited. MD, SV, and AM are also being supported by the Centers for Disease Control and Prevention, USA under Broad Agency Announcement (BAA) #75D30121C10566.