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How to Avoid Airborne Infection From Patients With COVID-19

The ways in which COVID-19 spreads from infected patients should be taken into consideration when determining hospital treatment, according to a new articles seeking to protect healthcare workers. Find out what procedures and encounters are more or less risky and the significance of droplet size in making those decisions.

KNOXVILLE, TN – For healthcare workers, one of the most alarming features of the novel coronavirus is how it can spread from infected patients through the air, potentially infecting care providers.

An article published online by the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine offers advice on how hospital pharmacists and other medical professionals can protect themselves.

https://www.atsjournals.org/doi/abs/10.1164/rccm.202004-1263PP

The perspective article is authored by Rajiv Dhand, MD, professor and chair, Department of Medicine and associate dean of clinical affairs, University of Tennessee Graduate School of Medicine in Knoxville, and Jie Li, PhD, RRT, associate professor, Department of Cardiopulmonary Services, Division of Respiratory Care, Rush University Medical Center in Chicago. The two describe the various types and sizes of virus-containing droplets present in sneezes and coughs, as well as where those deposit in the respiratory system and what medical procedures and devices are most likely to present risks during treatment.

"The apprehension about the use of aerosolized therapies in COVID-19 patients relates to their potential to spread infectious aerosols," Dhand explained. "Our recommendations offer a balanced, scientific perspective on the use of such aerosolized therapies in patients infected with SARS-CoV-2, the virus that causes COVID-19."

Various aerosol generating procedures (AGPs), such as suctioning or tracheal intubation can produce airborne particles, according to the article, which notes the issue also exists with aerosol generators, especially jet nebulizers.

"AGPs such as intubation, bronchoscopy, physiotherapy and suctioning generate potential infectious bioaerosols by provoking coughs and are associated with increased infection rates among employees working in health care," the authors write. "In contrast, AGPs such as oxygen therapy, use of humidified high-flow nasal cannula, non-invasive ventilation and manual ventilation via mask are less about 'generating' bioaerosols and more about 'dispersing' aerosols further away from the patient."

They emphasize, however, that aerosols produced by medical aerosol generators do not contain pathogens unless the aerosol device is contaminated.

One problem, the authors point out, is that evidence linking AGPs to spread of viral infections remains limited by the low quality of studies on the topic. Still, they make a range of recommendations for reducing the transmission of respiratory tract infections in line with guidelines from the national Centers for Disease Control and Prevention. Those include:

• Avoiding procedures that irritate airways and provoke violent coughing and try to reduce exposure to infectious aerosol.
• Staying six feet away, if possible, from infected patients, especially when the patient is coughing or sneezing.
• Instituting barriers, when using a mechanical ventilator, to filter the virus or reduce virus dispersion by placing a filter at the exhalation port of the ventilator or connecting a filter to the oxygen mask.
• Placing a surgical mask on a spontaneously breathing patient's face or using tissue to cover his or her mouth, especially during coughing, sneezing or talking, to reduce the dispersion distance or viral load.
• Using personal protective equipment for healthcare providers.
• Trying, when possible, to keep infected patients in single rooms to prevent droplet dispersion, although it is acceptable for two patients with the same infection that is spread by respiratory droplets to be in the same room.

"Coughs and sneezes create respiratory droplets of variable size that spread respiratory viral infections,” Dhand added. “Because these droplets are forcefully expelled, they are dispersed in the environment and can be exhaled by a susceptible host. While most respiratory droplets are filtered by the nose or deposit in the oropharynx, the smaller droplet nuclei become suspended in room air and individuals farther away from the patient may inhale them.”