Perceiving Nasal Patency through Mucosal Cooling Rather than Air Temperature or Nasal Resistance

Abstract

Adequate perception of nasal airflow (i.e., nasal patency) is an important consideration for patients with nasal sinus diseases. The perception of a lack of nasal patency becomes the primary symptom that drives these patients to seek medical treatment. However, clinical assessment of nasal patency remains a challenge because we lack objective measurements that correlate well with what patients perceive.The current study examined factors that may influence perceived patency, including air temperature, humidity, mucosal cooling, nasal resistance, and trigeminal sensitivity. Forty-four healthy subjects rated nasal patency while sampling air from three facial exposure boxes that were ventilated with untreated room air, cold air, and dry air, respectively. In all conditions, air temperature and relative humidity inside each box were recorded with sensors connected to a computer. Nasal resistance and minimum airway cross-sectional area (MCA) were measured using rhinomanometry and acoustic rhinometry, respectively. General trigeminal sensitivity was assessed through lateralization thresholds to butanol. No significant correlation was found between perceived patency and nasal resistance or MCA. In contrast, air temperature, humidity, and butanol threshold combined significantly contributed to the ratings of patency, with mucosal cooling (heat loss) being the most heavily weighted predictor. Air humidity significantly influences perceived patency, suggesting that mucosal cooling rather than air temperature alone provides the trigeminal sensation that results in perception of patency. The dynamic cooling between the airstream and the mucosal wall may be quantified experimentally or computationally and could potentially lead to a new clinical evaluation tool.

Empty Nose Syndrome

“…It is speculated that the sensation of nasal patency is largely dependent on mucosal cooling, wherein laminar airflow enters the nasal cavities and is distributed to all nasal cavity mucosa by turbulent flow from contact with the turbinates, driving local temperature and humidity changes [8][9][10]. TRPM8, a trigeminal cool thermoreceptor which is activated by menthol, has been implicated in producing the sensation of nasal patency as a response to mucosal cooling [5••, 8, 11].…”

Effects of CT resolution and radiodensity threshold on the CFD evaluation of nasal airflow

“…Therefore, it is not always possible to establish a causal link between the apparent status of the nose and the disruption of its physiological function. For example, the subjective sensation of good nasal airflow, the so-called nasal patency, has a great importance in patients with NBD, despite often bearing little to no relationship to the actual physical aerodynamic resistance or drag experienced by the airflow in the nose [18,31]. Furthermore, surgical procedures are typically carried out according to the surgeon's own experience.…”

Objective assessment of persistent rhinitis in Chinese and its relationship with serum indicators

“…It differs from the classic rhinomanometry method and measures nasal resistance via a dynamic procedure by calculating the nasal airway resistance during inspiration and expiration at different pressures [20]. However, the role of four-phase rhinomanometry in evaluating rhinology diseases is controversial [21,22]. Here, we used AP Max and AP T to avoid the effects of the nasal cycle and found that these were elevated only in the AR WO group.…”