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Otol Neurotol ; 42(4): 614-622, 2021 04 01.
Article in English | MEDLINE | ID: covidwho-1313901


HYPOTHESIS: Aerosols are generated during mastoidectomy and mitigation strategies may effectively reduce aerosol spread. BACKGROUND: An objective understanding of aerosol generation and the effectiveness of mitigation strategies can inform interventions to reduce aerosol risk from mastoidectomy and other open surgeries involving drilling. METHODS: Cadaveric and fluorescent three-dimensional printed temporal bone models were drilled under variable conditions and mitigation methods. Aerosol production was measured with a cascade impactor set to detect particle sizes under 14.1 µm. Field contamination was determined with examination under UV light. RESULTS: Drilling of cadaveric bones and three-dimensional models resulted in strongly positive aerosol production, measuring positive in all eight impactor stages for the cadaver trials. This occurred regardless of using coarse or cutting burs, irrigation, a handheld suction, or an additional parked suction. The only mitigation factor that led to a completely negative aerosol result in all eight stages was placing an additional microscope drape to surround the field. Bone dust was scattered in all directions from the drill, including on the microscope, the surgeon, and visually suspended in the air for all but the drape trial. CONCLUSIONS: Aerosols are generated with drilling the mastoid. Using an additional microscope drape to cover the surgical field was an effective mitigation strategy to prevent fine aerosol dispersion while drilling.

COVID-19/prevention & control , Mastoidectomy/adverse effects , Aerosols , COVID-19/transmission , Cadaver , Humans , Mastoidectomy/instrumentation , Mastoidectomy/methods , SARS-CoV-2
Ann Otol Rhinol Laryngol ; 130(11): 1245-1253, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1140414


OBJECTIVES: Define aerosol and droplet risks associated with routine otolaryngology clinic procedures during the COVID-19 era. METHODS: Clinical procedures were simulated in cadaveric heads whose oral and nasal cavities were coated with fluorescent tracer (vitamin B2) and breathing was manually simulated through retrograde intubation. A cascade impactor placed adjacent to the nares collected generated particles with aerodynamic diameters ≤14.1 µm. The 3D printed models and syringes were used to simulate middle and external ear suctioning as well as open suctioning, respectively. Provider's personal protective equipment (PPE) and procedural field contamination were also recorded for all trials using vitamin B2 fluorescent tracer. RESULTS: The positive controls of nebulized vitamin B2 produced aerosol particles ≤3.30 µm and endonasal drilling of a 3D model generated particles ≤14.1 µm. As compared with positive controls, aerosols and small droplets with aerodynamic diameter ≤14.1 µm were not detected during rigid nasal endoscopy, flexible fiberoptic laryngoscopy, and rigid nasal suction of cadavers with simulated breathing. There was minimal to no field contamination in all 3 scenarios. Middle and external ear suctioning and open container suctioning did not result in any detectable droplet contamination. The clinic suction unit contained all fluorescent material without surrounding environmental contamination. CONCLUSION: While patients' coughing and sneezing may create a baseline risk for providers, this study demonstrates that nasal endoscopy, flexible laryngoscopy, and suctioning inherently do not pose an additional risk in terms of aerosol and small droplet generation. An overarching generalization cannot be made about endoscopy or suctioning being an aerosol generating procedure. LEVEL OF EVIDENCE: 3.

Aerosols/adverse effects , COVID-19 , Disease Transmission, Infectious/prevention & control , Endoscopy , Otolaryngology , Risk Adjustment/methods , Suction , COVID-19/prevention & control , COVID-19/transmission , Cadaver , Endoscopy/adverse effects , Endoscopy/instrumentation , Endoscopy/methods , Humans , Otolaryngology/methods , Otolaryngology/standards , Outcome Assessment, Health Care , Personal Protective Equipment/classification , Personal Protective Equipment/virology , Research Design , Risk Assessment/methods , SARS-CoV-2 , Suction/adverse effects , Suction/instrumentation , Suction/methods
Ann Otol Rhinol Laryngol ; 130(3): 280-285, 2021 Mar.
Article in English | MEDLINE | ID: covidwho-714251


OBJECTIVE: During the COVID-19 era, a reliable method for tracing aerosols and droplets generated during otolaryngology procedures is needed to accurately assess contamination risk and to develop mitigation measures. Prior studies have not investigated the reliability of different fluorescent tracers for the purpose of studying aerosols and small droplets. Objectives include (1) comparing vitamin B2, fluorescein, and a commercial fluorescent green dye in terms of particle dispersion pattern, suspension into aerosols and small droplets, and fluorescence in aerosolized form and (2) determining the utility of vitamin B2 as a fluorescent tracer coating the aerodigestive tract mucosa in otolaryngology contamination models. METHODS: Vitamin B2, fluorescein, and a commercial fluorescent dye were aerosolized using a nebulizer and passed through the nasal cavity from the trachea in a retrograde-intubated cadaveric head. In another scenario, vitamin B2 was irrigated to coat the nasal cavity and nasopharyngeal mucosa of a cadaveric head for assessment of aerosol and droplet generation from endonasal drilling. A cascade impactor was used to collect aerosols and small droplets ≤14.1 µm based on average aerodynamic diameter, and the collection chambers were visualized under UV light. RESULTS: When vitamin B2 was nebulized, aerosols ≤5.4 µm were generated and the collected particles were fluorescent. When fluorescein and the commercial water tracer dye were nebulized, aerosols ≤8.61 µm and ≤2.08 µm respectively were generated, but the collected aerosols did not appear visibly fluorescent. Endonasal drilling in the nasopharynx coated with vitamin B2 irrigation yielded aerosols ≤3.30 µm that were fluorescent under UV light. CONCLUSION: Vitamin B2's reliability as a fluorescent tracer when suspended in aerosols and small droplets ≤14.1 µm and known mucosal safety profile make it an ideal compound compared to fluorescein and commercial water-based fluorescent dyes for use as a safe fluorescent tracer in healthcare contamination models especially with human subjects.

COVID-19/transmission , Disease Transmission, Infectious , Fluorescent Dyes , Models, Biological , Nasopharynx/surgery , Riboflavin , Aerosols , Cadaver , Endoscopy , Fluorescein , Humans , Models, Anatomic , Nebulizers and Vaporizers , Otolaryngology , Otorhinolaryngologic Surgical Procedures/methods , Particle Size , SARS-CoV-2