Aerosol emission from the respiratory tract: an analysis of aerosol generation from oxygen delivery systems.

Autor:	Hamilton FW; Infection Science, North Bristol NHS Trust, Westbury on Trym, UK fergus.hamilton@bristol.ac.uk.; MRC Integrative Epidemiology Unit, Bristol, UK., Gregson FKA; Bristol Aerosol Research Centre, School of Chemistry, University of Bristol, Bristol, UK., Arnold DT; Academic Respiratory Unit, North Bristol NHS Trust, Westbury on Trym, UK., Sheikh S; Bristol Aerosol Research Centre, School of Chemistry, University of Bristol, Bristol, UK., Ward K; Physiotherapy Department, North Bristol NHS Trust, Westbury on Trym, UK., Brown J; Anaesthetics and Intensive Care Department, North Bristol NHS Trust, Westbury on Trym, UK., Moran E; Infectious Diseases, North Bristol NHS Trust, Bristol, UK., White C; Research and Development, North Bristol NHS Trust, Westbury on Trym, UK., Morley AJ; Academic Respiratory Unit, North Bristol NHS Trust, Westbury on Trym, UK., Bzdek BR; Bristol Aerosol Research Centre, School of Chemistry, University of Bristol, Bristol, UK., Reid JP; Bristol Aerosol Research Centre, School of Chemistry, University of Bristol, Bristol, UK., Maskell NA; Academic Respiratory Unit, North Bristol NHS Trust, Westbury on Trym, UK., Dodd JW; MRC Integrative Epidemiology Unit, Bristol, UK.; Academic Respiratory Unit, North Bristol NHS Trust, Westbury on Trym, UK.
Jazyk:	angličtina
Zdroj:	Thorax [Thorax] 2022 Mar; Vol. 77 (3), pp. 276-282. Date of Electronic Publication: 2021 Nov 04.
DOI:	10.1136/thoraxjnl-2021-217577
Abstrakt:	Introduction: continuous positive airway pressure (CPAP) and high-flow nasal oxygen (HFNO) provide enhanced oxygen delivery and respiratory support for patients with severe COVID-19. CPAP and HFNO are currently designated as aerosol-generating procedures despite limited high-quality experimental data. We aimed to characterise aerosol emission from HFNO and CPAP and compare with breathing, speaking and coughing. Materials and Methods: Healthy volunteers were recruited to breathe, speak and cough in ultra-clean, laminar flow theatres followed by using CPAP and HFNO. Aerosol emission was measured using two discrete methodologies, simultaneously. Hospitalised patients with COVID-19 had cough recorded using the same methodology on the infectious diseases ward. Results: In healthy volunteers (n=25 subjects; 531 measures), CPAP (with exhalation port filter) produced less aerosol than breathing, speaking and coughing (even with large >50 L/min face mask leaks). Coughing was associated with the highest aerosol emissions of any recorded activity. HFNO was associated with aerosol emission, however, this was from the machine. Generated particles were small (<1 µm), passing from the machine through the patient and to the detector without coalescence with respiratory aerosol, thereby unlikely to carry viral particles. More aerosol was generated in cough from patients with COVID-19 (n=8) than volunteers. Conclusions: In healthy volunteers, standard non-humidified CPAP is associated with less aerosol emission than breathing, speaking or coughing. Aerosol emission from the respiratory tract does not appear to be increased by HFNO. Although direct comparisons are complex, cough appears to be the main aerosol-generating risk out of all measured activities. Competing Interests: Competing interests: None declared. (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)
Databáze:	MEDLINE
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