An in vitro investigation into the release of fugitive medical aerosols into the environment during manual ventilation.

BACKGROUND: During manual resuscitation, nebulizer therapy may be used to deliver therapeutics to patients in respiratory distress. However, the devices used to generate and deliver these medical aerosols have the potential to release these therapeutics into the local environment and expose caregivers to unwanted medical aerosols. AIM: To quantify the levels of fugitive medical aerosol released into the environment during aerosol drug delivery using a manual resuscitation bag with and without filtration. METHODS: Time-varying fugitive aerosol concentrations were measured using an aerodynamic particle sizer placed at a position designed to mimic a caregiver. Two nebulizer types were assessed, a vibrating mesh nebulizer and a jet nebulizer. The aerosol dose delivered to the simulated patient lung was also quantified. FINDINGS: Filtration of the exhalation port of the manual resuscitation bag was seen to reduce fugitive medical aerosols to ambient levels for both nebulizer types. The vibrating mesh nebulizer delivered the greatest quantity of aerosol to the simulated adult patient (18.44 ± 1.03% versus 3.64 ± 0.26% with a jet nebulizer). CONCLUSIONS: The results highlight the potential for exposure to fugitive medical aerosols released during the delivery of aerosol therapy with a manual resuscitation bag and also the potential for significant variation in patient lung dose depending on nebulizer type.

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

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.