Aerosol emission from the respiratory tract: an analysis of relative risks from oxygen delivery systems

作者：Fergus Hamilton, Florence K. A. Gregson, David Arnold, Sadiyah Sheikh, Kevin R. Ward, Julian Brown, E. J. MORAN, Charles S. White, Anna Morley, AERATOR group, Bryan R. Bzdek, Jonathan P. Reid, Nick Maskell, James Dodd · 发表于：medRxiv · 年份：2021 · DOI：10.1101/2021.01.29.21250552 · 被引用次数：33 · 研究领域：Infection Control and Ventilation、Inhalation and Respiratory Drug Delivery、COVID-19 and healthcare impacts

Background Risk of aerosolisation of SARS-CoV-2 directly informs organisation of acute healthcare and PPE guidance. Continuous positive airways pressure (CPAP) and high-flow nasal oxygen (HFNO) are widely used modes of oxygen delivery and respiratory support for patients with severe COVID-19, with both considered as high risk aerosol generating procedures. However, there are limited high quality experimental data characterising aerosolisation during oxygen delivery and respiratory support. Methods Healthy volunteers were recruited to breathe, speak, and cough in ultra-clean, laminar flow theatres followed by using oxygen and respiratory support systems. Aerosol emission was measured using two discrete methodologies, simultaneously. Hospitalised patients with COVID-19 were also recruited and had aerosol emissions measured during breathing, speaking, and coughing. Findings In healthy volunteers (n = 25 subjects; 531 measures), CPAP (with exhalation port filter) produced less aerosols than breathing, speaking and coughing (even with large >50L/m facemask leaks). HFNO did emit aerosols, but the majority of these particles were generated from the HFNO machine, not the patient. HFNO-generated particles were small (<1μm), passing from the machine through the patient and to the detector without coalescence with respiratory aerosol, thereby unlikely to carry viral particles. Coughing was associated with the highest aerosol emissions with a peak concentration at least 10 times gr...