American Association for Aerosol Research - Abstract Submission

AAAR 38th Annual Conference
October 5 - October 9, 2020

Virtual Conference

Abstract View


Quantifying the Relative Risk of Aerosol Generating Procedures in Clinical Settings

FLORENCE GREGSON, Jules Brown, Bryan R. Bzdek, Andrew Shrimpton, Tony Pickering, Jonathan P. Reid, University of Bristol

     Abstract Number: 463
     Working Group: The Role of Aerosol Science in the Understanding of the Spread and Control of COVID-19 and Other Infectious Diseases

Abstract
The risk of SARS-CoV-2 transmission to and by healthcare workers in clinical settings is a pressing issue. Many activities are classified as Aerosol Generating Procedures (AGPs), including (in the UK) intubation, extubation, and manual ventilation. These procedures are thought to produce aerosols and droplets that may spread disease. Consequently, such procedures require enhanced personal protective equipment (PPE, including facemask respirators, fluid resistant gowns, and face shields) and strategies to minimise exposure of other staff have been implemented (e.g. minimal staff present during AGPs; delays after each AGP to allow air changes). These enhanced safety precautions increase cost, decrease throughput, and inhibit communication among clinicians. However, the actual exposure (and risk of disease transmission) during many AGPs is unknown because the evidence base is lacking. For instance, the concentration and size distribution of aerosol produced during AGPs is poorly known.
In this study, a Condensational Particle Counter (CPC, < 1 μm particles) and Optical Particle Sizer (OPS, 300 nm – 10 μm) were deployed to quantify the number concentration (CPC, OPS) and size distribution (OPS) of aerosol produced during AGPs in a laminar flow operating theatre over a period of several weeks. The near-zero particle background in the operating theatre allowed sensitive measurements of aerosol production from individual coughs (showing a characteristic particle size distribution) and concentration. Aerosol production during intubation and extubation were compared to aerosol production from voluntary coughs. We will present our data quantitating the relative risk of aerosol production associated with AGPs which should prompt a re-evaluation of current practice.