Aerosol-Generating Potential of Topical Nasal Preparation Before Nasoendoscopy: A Quantitative Study

The aerosol-generating capacity of nasal sprays is an important but controversial topic, with mixed evidence in the literature. This study aims to quantitatively analyze the amount of aerosol generated by the use of topical nasal sprays prior to nasoendoscopy.

A cohort study was conducted in a simulated outpatient ambulatory clinic. Healthy volunteers were recruited and underwent nasal spraying with normal saline containing 0.1% w/v fluorescein, using a commercially available spray system (Co-Phenylcaine Forte; ENT Technologies Pty Ltd., Victoria, Australia), within an enclosed cabin. Cabin air was sampled with a filter that trapped fluorescein, which was extracted and quantified with a fluorescence spectrometer. This was compared to background noise, represented by fluorescence quantified in cabin air sampled before nasal spraying. Statistical analysis was performed with the Wilcoxon signed rank test. Multi-variable analysis was performed with a quantile regression model.

A total of 30 healthy volunteers were recruited. The median (IQR) concentration of fluorescein quantified with NSF spray using the standard nozzle was 20.9 (8.3-53.5) ng/mL, which was significantly higher than background noise [1.7 (1.0-2.2) ng/mL; median difference 18.9, 95% CI (10.8, 36.7), p < 0.001]. Multi-variable analysis showed that age, gender, and ethnicity were not significantly associated with the amount of fluorescein aerosolization.

Preparing the nose with topical sprays could be associated with aerosol generation. Clinicians and stakeholders will need to weigh the risks and benefits of using pre-endoscopic nasal preparation sprays and institute mitigation measures as necessary.

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