SARS-CoV-2, the virus that causes Covid-19, is so infectious that protecting health care workers from it as they treat patients is an important issue in the fight against this pandemic. Reliable personal protective equipment is central to that cause. But recent innovations, like so-called intubation boxes, could do more harm than good.

A key way the virus is spread is through tiny airborne particles. That’s why health care workers need to use protective equipment such as N95 masks or powered air-purified respirators. The right protective equipment is especially important during intubation — placing a breathing tube into a patient’s airway and then connecting it to a ventilator that essentially breathes for the patient.

Intubation generates airborne virus particles that can spread Covid-19 to nearby health care workers. As the demand for N95 masks and other personal protective equipment outstrips the supply in some hospitals, researchers have risen to the challenge by developing new ways to contain the spread of the virus during intubation. We applaud these efforts, but caution that they should first be proven to do what they claim to do before they are used in hospitals.

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In late March, anesthesiologist Hsien Yung Lai released plans for what he called an Aerosol Box to protect health care workers during intubation procedures. It’s a clear plastic box about the size of a file crate that is placed over a patient’s head and shoulders before intubation. Holes in the box for a clinician’s hands allow him or her to perform the procedure while theoretically being shielded from viral droplets generated during intubation.

Since then, other companies and organizations have followed suit with their own versions, generally known as intubation boxes. News reports show them being made and being used in the U.S. and around the world. Numerous campaigns on GoFundMe.com have collectively raised over one-quarter of a million dollars to manufacture and distribute these boxes.

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Manufacturers of the boxes claim they protect health care workers from being exposed to aerosolized virus particles during intubation. The concept is simple, and the extra barrier seems to ease fear and anxiety among health care workers.

Even a recent letter to the editor in the New England Journal of Medicine said that intubation boxes provide protection from heavier particles called droplets, which typically fall to the ground within seconds, though the authors provided no data about whether the boxes protect health care workers from invisible aerosolized virus particles, which have the potential to stay in the air for hours and can be scattered by even slight air currents.

To the best of our knowledge, there has been no safety testing done to ensure that the boxes do indeed prevent the spread of aerosolized virus particles during intubation, a glaring omission if health care workers are counting on them for protection.

We enlisted the help of industrial air filtration experts to test the safety of commercially available intubation boxes and determine if they protected health care workers from aerosolized SARS-CoV-2 during intubation. They employed the same series of safety tests used to certify laboratory hoods which researchers use when handling dangerous aerosols.

To assess if the physical barrier provided by intubation boxes is enough to contain airborne virus particles, white vapor is generated inside the box to simulate a patient’s exhaled breaths. During simulated intubations, this vapor billowed out of the box into the surrounding environment and onto the nearby health care workers.

Intubation boxes seem like a simple solution to a difficult problem. It’s unfortunate that they do not seem to provide as much protection as many would have hoped.

Measurable standards have been set for all types of personal protective equipment, from N95 masks to face shields. Health care workers should be confident that any equipment they use will protect them from Covid-19 infection as they treat patients.

Creative and well-intentioned people are undertaking the laudable work of developing new ways to protect health care workers from infection during the Covid-19 pandemic. But it is absolutely essential that their efforts be rigorously tested before they are put into use. Otherwise they can create a false sense of security.

Relying on protection that doesn’t work is more dangerous than not having any protection at all.

David Turer is the chief resident in plastic surgery at the University of Pittsburgh Medical Center as well as an electrical and biomedical engineer. Jason Chang is an emergency medicine physician and associate chief of emergency services for the UPMC Magee-Women’s Hospital. Heng Ban is a professor of mechanical engineering and director of the nuclear engineering program at the University of Pittsburgh Swanson School of Engineering.

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