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Evaluation of Aerosol Containment of Barrier Devices Used for Airway Management: Methodological Development and Efficacy Studies
CHRISTOPHER NIEDEK, Richard Fidler, Jan Hirsch, David Robinowitz, Qi Zhang, University of California, Davis
Abstract Number: 437
Working Group: The Role of Aerosol Science in the Understanding of the Spread and Control of COVID-19 and Other Infectious Diseases
Abstract
There is mounting evidence for SARS-CoV-2 transmission via bioaerosols emitted by infected individuals. This has prompted the use of barrier devices for bioaerosol containment in hospital settings. These devices are commonly named “aerosol boxes” despite the lack of empirical evidence demonstrating that such devices can effectively contain aerosols. Our group has designed a methodology for evaluating the aerosol containment capability of barrier devices and have performed testing on several designs.
Aerosols are generated from a solution of known composition and low instrumental background. The aerosols are then directed into a simulation manikin’s airway and ejected out of the manikin’s mouth, simulating respiration. For comparison, the barrier devices are placed over the head of the manikin. Using concurrent measurements from a high-resolution time-of-flight aerosol mass spectrometer and a condensation particle counter, aerosol leaks outside of barrier devices can be qualitatively and quantitatively compared at pre-defined positions.
The results suggest aerosols can leak through incompletely sealed arm holes and edges of the barrier devices. Unsealed arm holes may inadvertently direct aerosols towards the healthcare worker using the device for protection, in particular if the foot end of the barrier device is sealed. Moreover, a plume of aerosol may be released when removing the barrier devices. This can be avoided if care is taken to evacuate particulate matter from the device prior to removal with a suction device.
The methodology described here demonstrates the feasibility of determining aerosol containment efficacy of barrier devices. This study utilized inorganic aerosols and thus potential infection from exposure to leaked aerosols was not explored. However, preliminary data indicates the need for caution when employing barrier devices for bioaerosol containment. Our results demonstrate that barrier devices cannot replace other types of personal protective equipment when performing airway management in potentially infective patients.