Reducing Aerosol-Related Risk of Transmission in the Era of COVID-19: An Interim Guidance Endorsed by the International Society of Aerosols in Medicine

Abstract

National and international guidelines recommend droplet/airborne transmission and contact precautions for those caring for coronavirus disease 2019 (COVID-19) patients in ambulatory and acute care settings. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, an acute respiratory infectious agent, is primarily transmitted between people through respiratory droplets and contact routes. A recognized key to transmission of COVID-19, and droplet infections generally, is the dispersion of bioaerosols from the patient. Increased risk of transmission has been associated with aerosol generating procedures that include endotracheal intubation, bronchoscopy, open suctioning, administration of nebulized treatment, manual ventilation before intubation, turning the patient to the prone position, disconnecting the patient from the ventilator, noninvasive positive-pressure ventilation, tracheostomy, and cardiopulmonary resuscitation. The knowledge that COVID-19 subjects can be asymptomatic and still shed virus, producing infectious droplets during breathing, suggests that health care workers (HCWs) should assume every patient is potentially infectious during this pandemic. Taking actions to reduce risk of transmission to HCWs is, therefore, a vital consideration for safe delivery of all medical aerosols. Guidelines for use of personal protective equipment (glove, gowns, masks, shield, and/or powered air purifying respiratory) during high-risk procedures are essential and should be considered for use with lower risk procedures such as administration of uncontaminated medical aerosols. Bioaerosols generated by infected patients are a major source of transmission for SARS CoV-2, and other infectious agents. In contrast, therapeutic aerosols do not add to the risk of disease transmission unless contaminated by patients or HCWs.

Guidance on nebulization during the current COVID-19 pandemic

“…The virus can be transmitted either directly by inhalation of fine droplets expelled from an infected person or during aerosol-generating procedures on an infected individual. Therefore, bioaerosols generated by infected patients are a major potential source of transmission for SARS CoV-2 and other infectious agents [4].…”

“…It is therefore easy to understand why national and international guidelines recommend droplet/airborne and contact precautions for those caring for COVID-19 patients in ambulatory and acute care settings [4]. Increased risk of transmission has been associated with aerosol generating procedures that include endotracheal intubation, bronchoscopy, open suctioning, administration of nebulized treatment, manual ventilation before intubation, turning the patient to the prone position, disconnecting the patient from the ventilator, noninvasive positive-pressure ventilation, tracheostomy, cardiopulmonary resuscitation [4]. Some of these procedures, such as intubation, open suctioning, tracheotomy, manual ventilation, and bronchoscopy can significantly increase the risk of production of bioaerosols possibly containing pathogens by the patient [4].…”

“…Increased risk of transmission has been associated with aerosol generating procedures that include endotracheal intubation, bronchoscopy, open suctioning, administration of nebulized treatment, manual ventilation before intubation, turning the patient to the prone position, disconnecting the patient from the ventilator, noninvasive positive-pressure ventilation, tracheostomy, cardiopulmonary resuscitation [4]. Some of these procedures, such as intubation, open suctioning, tracheotomy, manual ventilation, and bronchoscopy can significantly increase the risk of production of bioaerosols possibly containing pathogens by the patient [4]. Others procedures, such as oxygen administration, high-flow nasal oxygen, and use of medical aerosols potentially act to disperse bioaerosols from the patient to the surrounding area but there is not evidence that they generate additional contaminated aerosols [4].…”

“…Some of these procedures, such as intubation, open suctioning, tracheotomy, manual ventilation, and bronchoscopy can significantly increase the risk of production of bioaerosols possibly containing pathogens by the patient [4]. Others procedures, such as oxygen administration, high-flow nasal oxygen, and use of medical aerosols potentially act to disperse bioaerosols from the patient to the surrounding area but there is not evidence that they generate additional contaminated aerosols [4].…”

“…In any case, it has been pointed out that exhaled bioaerosols whether from cough or normal exhalation are neither avoided nor limited with use of pMDIs, DPIs or SMIs [4]. In effect, characteristics of drug formulation can precipitate cough with these inhalers [17].…”