Aerosol Generation During Laryngology Procedures in the Operating Room.

OBJECTIVE: Severe acute respiratory syndrome coronavirus-2 spreads through respiratory fluids. We aim to quantify aerosolized particles during laryngology procedures to understand their potential for transmission of infectious aerosol-based diseases. STUDY DESIGN: Prospective quantification of aerosol generation. METHODS: Airborne particles (0.3-25 µm in diameter) were measured during live-patient laryngology surgeries using an optical particle counter positioned 60 cm from the oral cavity to the surgeon's left. Measurements taken during the procedures were compared to baseline concentrations recorded immediately before each procedure. Procedures included direct laryngoscopy with general endotracheal anesthesia (GETA), direct laryngoscopy with jet ventilation, and carbon dioxide (CO2 ) laser use with or without jet ventilation, all utilizing intermittent suction. RESULTS: Greater than 99% of measured particles were 0.3 to 1.0 µm in diameter. Compared to baseline, direct laryngoscopy was associated with a significant 6.71% increase in cumulative particles, primarily 0.3 to 1.0 µm particles (P < .0001). 1.0 to 25 µm particles significantly decreased (P < .001). Jet ventilation was not associated with a significant change in cumulative particles; when analyzing differential particle sizes, only 10 to 25 µm particles exhibited a significant increase compared to baseline (+42.40%, P = .002). Significant increases in cumulative particles were recorded during CO2 laser use (+14.70%, P < .0001), specifically in 0.3 to 2.5 µm particles. Overall, there was no difference when comparing CO2 laser use during jet ventilation versus GETA. CONCLUSIONS: CO2 laser use during laryngology surgery is associated with significant increases in airborne particles. Although direct laryngoscopy with GETA is associated with slight increases in particles, jet ventilation overall does not increase particle aerosolization. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:2759-2765, 2021.

Aerosol and Droplet Risk of Common Otolaryngology Clinic Procedures.

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.

Quantification of Aerosol Concentrations During Endonasal Instrumentation in the Clinic Setting.

OBJECTIVE: Recent anecdotal reports and cadaveric simulations have described aerosol generation during endonasal instrumentation, highlighting a possible risk for transmission of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) during endoscopic endonasal instrumentation. This study aims to provide a greater understanding of particle generation and exposure risk during endoscopic endonasal instrumentation. STUDY DESIGN: Prospective quantification of aerosol generation during office-based nasal endoscopy procedures. METHODS: Using an optical particle sizer, airborne particles concentrations 0.3 to 10 microns in diameter, were measured during 30 nasal endoscopies in the clinic setting. Measurements were taken at time points throughout diagnostic and debridement endoscopies and compared to preprocedure and empty room particle concentrations. RESULTS: No significant change in airborne particle concentrations was measured during diagnostic nasal endoscopies in patients without the need for debridement. However, significant increases in mean particle concentration compared to preprocedure levels were measured during cold instrumentation at 2,462 particles/foot3 (95% CI 837 to 4,088; P = .005) and during suction use at 2,973 particle/foot3 (95% CI 1,419 to 4,529; P = .001). In total, 99.2% of all measured particles were ≤1 µm in diameter. CONCLUSION: When measured with an optical particle sizer, diagnostic nasal endoscopy with a rigid endoscope is not associated with increased particle aerosolization in patient for whom sinonasal debridement is not needed. In patients needing sinonasal debridement, endonasal cold and suction instrumentation were associated with increased particle aerosolization, with a trend observed during endoscope use prior to tissue manipulation. Endonasal debridement may potentially pose a higher risk for aerosolization and SARS-CoV-2 transmission. Appropriate personal protective equipment use and patient screening are recommended for all office-based endonasal procedures. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E1415-E1421, 2021.