(755b) Aerosol Generation during Routine Otolaryngology Procedures and the Effect of Hepa Filtration on Aerosol Concentrations

The SARS COVID pandemic has highlighted safety concerns for healthcare workers exposed to potentially aerosol-borne communicable diseases. Healthcare workers working in otolaryngology may be particularly at risk due to the prevalence of the SARS CoV-2 virus in the nares. In response, measures like use of HEPA filters and increased turnover times have been implemented to safeguard against these aerosolized particles. However, prospective investigations have not clearly defined aerosolization or how HEPA filtration affects in-clinic aerosol concentrations. The purpose of this study was to determine whether increased aerosol concentrations are associated with patients undergoing nasal endoscopy and to determine the effectiveness of HEPA filtration in reducing aerosol concentrations in the clinic.

Patients were prospectively enrolled in a cross-sectional study at a tertiary medical center. Demographic information, as well as clinic room characteristics, such as room size and air exchange with and without a HEPA filter, were measured and recorded. Clinic personnel also recorded activities in the clinic room, which were subsequently aligned with aerosol concentrations. A scanning mobility particle sizer, aerosol particle sizer, and GRIMM aerosol monitor measured aerosolized particles ranging from 14.3 nm to 34 µm. Associations between aerosol concentration, nasal endoscopy, and use of HEPA filter were assessed. Room turnover times needed to achieve baseline aerosol concentration were also calculated.

A total of 48 patients met inclusion criteria (29 with nasal endoscopy and 19 without (control)). The two patient cohorts exhibited no significant differences in age or gender. Aerosol concentrations among the nasal endoscopy cohort were greater than those in the control group (p<0.05). The coughing/sneezing event, followed by the patient/provider discussion events resulted in the highest aerosol concentrations. Aerosol concentrations returned to baseline within 8.76 minutes without the use of a HEPA filter versus. 4.79 minutes with a HEPA filter (p=<0.01). This translated into an air change exchange per hour value of 2.14 and 4.17, with and without HEPA filtration, respectively.