ABSTRACT Objective Nasal airflow is essential for delivering odorants to the olfactory epithelium. With increasing evidence demonstrating a strong link between nasal airflow and olfaction, we conducted a large multicenter retrospective study to further examine if nasal airflow can influence olfactory recovery in patients with COVID‐19‐related olfactory dysfunction (C19OD). Methods Patients with reported C19OD received Sniffin’ Sticks extended set, peak nasal inspiratory flow (PNIF), and VAS for smell (sVAS) at baseline (T 0 ). Subjects with a confirmed OD at T 0 were offered a second follow‐up, averaged at 6 months (T 1 ). All tests were repeated at T 1 . Results Two hundred and five patients (median age 46) with a median length of OD of 1.1 years were seen at T 0 . One hundred and eleven dysosmics at T 0 were seen at T 1 . At T 1 43 patients (38.7%) recovered their sense of smell. A statistically significant improvement was observed for PNIF ( p = 0.001) and sVAS ( p < 0.001) in the whole population at T 1 . A statistically significant difference was noted for all the olfactory scores and sVAS ( p < 0.001 for all) between normosmic and dysosmic subjects at T 1 . When we looked at changes in the scores between T 0 – T 1 , statistically significant correlations were observed between changes (Δ) in PNIF and Δthreshold (rho = 0.24 and p = 0.015), ΔPNIF and ΔTDI (rho = 0.22 and p = 0.021). An increase in ΔPNIF of 77.4 L/min corresponded to a 65% probability of reaching the normosmic level, with olfactory threshold being the more sensitive to PNIF changes. Conclusion Improvement in nasal airflow can have a positive impact on smell recovery and on olfactory threshold in particular, highlighting its importance in persistent C19OD. Level of Evidence 3.
Pendolino et al. (Wed,) studied this question.
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