Study: Protective Aerosol Box Used During COVID-19 Intubation Increases Exposure to Airborne Particles

As increasing numbers of COVID-19 patients require intubation, aerosol containment devices have been in high demand, including improvised protection strategies and devices.

Although aerosol boxes have been used in hospitals around the world to protect health care workers during the coronavirus disease 2019 (COVID-19) pandemic, new research suggests that aerosol boxes actually increase exposure to airborne particles when used during intubation.

Severely infected patients often require mechanical ventilation and the process of intubation often places health workers at the highest risk for exposure to the virus, according to a press release. As a result, aerosol containment devices have been in high demand, including improvised protection strategies and devices.

Despite the demand, the researchers noted increasing concerns from medical professionals that these devices are either not helping or are potentially exposing workers to harm. However, because these concerns have not been widely studied or disproven, the devices have continued to be widely used.

In an effort to investigate the concerns, researchers performed a study in a self-contained intensive care unit room using 7 adult volunteers who took turns in random order acting as the patient or the physician. The study simulated exposure of the laryngoscopist to airborne particles sized 0.3 to 5.0 macrons using 5 aerosol containment methods, including an aerosol box, a sealed box with and without suction, a vertical drape, and a horizontal drape. Each volunteer did all 6 trials (each intervention plus no intervention), generating 42 sets of results.

Each volunteer held a bottle of fluid just under their mouth and coughed every 30 seconds over 5 minutes. Particle detection devices were used to count different sizes particles and to assess particle spread.

Notably, compared with no intervention, the aerosol box showed an increase in airborne particle exposure of all sizes over 5 minutes, suggesting that the aerosol box was increasing exposure to COVID-19 particles. This increase was often by a factor of 5 times or more.

“We were surprised to find airborne particle contamination of the doctor increased substantially using the aerosol box compared with all other devices and with no device use,” the authors said in a statement. “Spikes of airborne particles were clearly seen, coinciding with patient coughing. We hypothesize that these represent particles escaping from the arm access holes in the aerosol box.”

Based on these findings, they concluded that such devices have minimal to no benefit in containing aerosols during a procedure and may actually increase exposure to airborne particles. They added that the use of any aerosol containment device has been eliminated from their protocols until their safety can be properly established.

“If this box were sold as a product, and therefore regulated, it would likely need to be immediately recalled due to a potential infection risk to the health care worker,” said author Peter Chan, PhD, in a statement. “Unfortunately, because these devices have been donated and are not regulated in any way, health care workers might be continuing to increase their exposure to COVID-19 while thinking they are protecting themselves.”

REFERENCE

Study shows that aerosol box used to protect healthcare workers during COVID intubation increases, rather than decreases, exposure to airborne particles [news release]. Association of Anaesthetists; July 10, 2020. https://anaesthetists.org/Home/News-opinion/News/Aerosol-boxes-and-COVID-19. Accessed July 16, 2020.