Quantification of Aerosol Concentrations During Endonasal Instrumentation in the Clinic Setting

Abstract

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.

Keywords: COVID-19; aerosol-generating procedures; droplet quantification; nasal endoscopy; optical particle sizer.

Fig. 1

Changes in mean particle concentration during nasal endoscopy with debridement. Preprocedure measurements demonstrated a mean particle concentration of 5,539 particle/foot³ (p/ft³), which were normalized to zero for comparison of mean particle concentrations of subsequent instrumentation. Endoscope use was associated with a mean particle concentration of 7,169 p/ft³ and a mean difference of 1,629 p/ft³ (95% CI −96 to 3,354; P = .063) from preprocedure concentrations. Cold instrumentation was associated with a mean particle concentration of 8,002 p/ft³ and a mean difference of 2,462 p/ft³ (95% CI 837 to 4,088; P = .005) from preprocedure concentrations. Suction use was associated with a mean particle concentration of 8,514 p/ft³ and a mean difference of 2,973 p/ft³ (95% CI 1,419 to 4,529; P = .001) from preprocedure concentrations. Measurements taken at the end of the procedure demonstrated a mean particle concentration of 5,816 p/ft³ with a mean difference of 276 p/ft³ (95% CI −1,120 to 1,673; P = .683).

Fig. 2

Difference in mean particle concentrations between diagnostic nasal endoscopy and nasal endoscopy with debridement. Zero reference normalized to combined preprocedure data in the cohort. Endoscope use during diagnostic endoscopy was associated with a nonsignificant mean particle difference of 173 p/ft³ (95% CI −1,139 to 793; P = .698) compared to preprocedure levels. Endoscope use prior to tissue manipulation in nasal endoscopy with debridement was associated with a trending mean increase of 1,629 p/ft³ (95% CI −96 to 3,354; P = .063).

Fig. 3

Mean particle concentrations with particle size distribution during nasal endoscopy with debridement. Particle measurements obtained during nasal endoscopies with debridement showed greater than 72% of all measured particles were 0.3 μm in diameter, greater than 22% were measured at 0.5 μm in diameter, and greater than 4% was measured at 1.0 μm in diameter. Particles sizes in the range of 2.5 to 10 μm in diameter composed less than 1% of all particles measured during nasal endoscopies with debridement.