Effect of wearing an N95 respirator on the internal nasal valve and the association with external nasal anatomy - a cohort study

Objectives To determine whether: the N95 respirator affects nasal valve patency; placement on the bony vault improves patency; and external nasal anatomy affects the outcome. Methods A prospective study with 50 participants was conducted. Nasal patency was measured by the minimal cross-sectional area via acoustic rhinometry, and using the Nasal Obstruction Symptom Evaluation survey, before and after wearing the N95 respirator and after adjustment. Results The minimal cross-sectional area was narrowed by 27 per cent when wearing the N95 respirator (p < 0.001), and improved by 9.2 per cent after adjustment (p = 0.003). The total Nasal Obstruction Symptom Evaluation score increased from 10.2 to 25.4 after donning the N95 respirator (p < 0.001), and decreased from 25.4 to 15.6 after adjustment (p < 0.001). There was no correlation with external nasal anatomy parameters. Conclusion Wearing the N95 respirator causes narrowing of the nasal valve, and adjustment onto the bony vault improves symptoms. The findings were not affected by external nasal anatomy.