key: cord-0926974-yt8t8mvq
authors: Lazzaro, Richard S.; Inra, Matthew L.; Patton, Byron
title: Commentary: Covid 19: don't throw caution to the wind nor air leak. Use PPE!
date: 2021-02-15
journal: Semin Thorac Cardiovasc Surg
DOI: 10.1053/j.semtcvs.2020.12.022
sha: 523d7322a213530a823cfe34c6257e59f21edf5e
doc_id: 926974
cord_uid: yt8t8mvq

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equipment (PPE) is recommended for these procedures including gown, gloves, eye protection, and N-95 mask. Little evidence is available regarding the risk to healthcare workers in the special circumstance of a patient with a chest tube and air leak.

In this original article, Mustaev and colleagues sought to define the degree of aerosolization from chest tube drainage systems in the context of the COVID-19 pandemic (2) . They conceptualized and developed a novel simulation model for measuring aerosol generation by agitating a fluorescent fluid with different air flow rates. The aerosolized particles were measured under ultraviolet light. They concluded that the single chamber chest drainage system is much more likely to generate aerosols than a three-chamber or digital drainage system and therefore, single chambers should not be used in patients with air leak (2).

Other researchers have detected that even loud speech can "emit thousands of oral fluid droplets per second" using highly sensitive laser light scattering observations (3). This technique and others allow for measurement of droplets as small as 0.5 µm. In the authors' study, the smallest droplet detected measured 56 µm with a mean size of 152 µm suggesting that many smaller droplets may not have been detected with their simulation and that the degree of aerosol generation is underestimated.

But merely demonstrating that speech or air leaks generate aerosols does not prove transmissibility. Infection is dependent on "the route of exposure, the size of the inoculum, the duration of the exposure, and host defenses (1) ." Another study aerosolized SARS-CoV-2 and found that the virus "retained infectivity and virion integrity for up to 16 hours in aerosols" and "may be a more important exposure transmission pathway than previously considered (4) ." The jury is still out on the impact of airborne transmission in the non-simulated, real world but these factors must be considered in protecting those at risk of exposure.

While this article is immediately relevant to many thoracic surgeons and other healthcare personnel across the globe, it is clear that PPE is required when in close proximity to patients with suspected or proven COVID-19. These patients are at increased risk of pneumothorax and bronchopleural fistula requiring chest tube drainage with prolonged air leaks. Three chamber or digital drainage systems should be used in this setting to minimize aerosolization and contamination of the environment but are not a substitute for PPE. Don't throw caution to the wind nor air leak.

Airborne Transmission of SARS-CoV-2: Theoretical Considerations and Available Evidence

Simulation and Measurement of Aerosolisation in Different Chest Drainage Systems

The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission

Persistence of Severe Acute Respiratory Syndrome Coronavirus 2 in Aerosol Suspensions