Correlation of Nasal Mucosal Temperature With Subjective Nasal Patency in Healthy Individuals

Abstract

Importance: Historically, otolaryngologists have focused on nasal resistance to airflow and minimum airspace cross-sectional area as objective measures of nasal obstruction using methods such as rhinomanometry and acoustic rhinometry. However, subjective sensation of nasal patency may be more associated with activation of cold receptors by inspired air than with respiratory effort.

Objective: To investigate whether subjective nasal patency correlates with nasal mucosal temperature in healthy individuals.

Design, setting, and participants: Healthy adult volunteers first completed the Nasal Obstruction Symptom Evaluation (NOSE) and a unilateral visual analog scale to quantify subjective nasal patency. A miniaturized thermocouple sensor was then used to record nasal mucosal temperature bilaterally in 2 locations along the nasal septum: at the vestibule and across from the inferior turbinate head.

Main outcomes and measures: Nasal mucosal temperature and subjective patency scores in healthy individuals.

Results: The 22 healthy adult volunteers (12 [55%] male; mean [SD] age, 28.3 [7.0] years) had a mean (SD) NOSE score of 5.9 (8.4) (range, 0-30) and unilateral VAS score of 1.2 (1.4) (range, 0-5). The range of temperature oscillations during the breathing cycle, defined as the difference between end-expiratory and end-inspiratory temperatures, was greater during deep breaths (mean [SD] change in temperature, 6.2°C [2.6°C]) than during resting breathing (mean [SD] change in temperature, 4.2°C [2.3°C]) in both locations (P < .001). Mucosal temperature measured at the right vestibule had a statistically significant correlation with both right-side visual analog scale score (Pearson r = -0.55; 95% CI, -0.79 to -0.17; P = .008) and NOSE score (Pearson r = -0.47; 95% CI, -0.74 to -0.06; P = .03). No other statistically significant correlations were found between mucosal temperature and subjective nasal patency scores. Nasal mucosal temperature was lower (mean of 1.5°C lower) in the first cavity to be measured, which was the right cavity in all participants.

Conclusions and relevance: The greater mucosal temperature oscillations during deep breathing are consistent with the common experience that airflow sensation is enhanced during deep breaths, thus supporting the hypothesis that mucosal cooling plays a central role in nasal airflow sensation. A possible correlation was found between subjective nasal patency scores and nasal mucosal temperature, but our results were inconsistent. The higher temperature in the left cavity suggests that the sensor irritated the nasal mucosa, affecting the correlation between patency scores and mucosal temperature. Future studies should consider noncontact temperature sensors to prevent mucosa irritation.

Level of evidence: NA.

Figures

FIGURE 1. Diagram of the sites measured

Nasal mucosal temperature was measured at (1) the nasal septum at the nasal vestibule and (2) the nasal septum across from the head of the inferior turbinate. Dotted lines show the location of the nasal turbinates and the junction between squamous and respiratory epithelium near the nasal valve.

FIGURE 2. Higher inhalation rate during deep breathing increases the range of nasal mucosal temperature oscillations during the breathing cycle

(A) Nasal mucosal temperature versus time recorded at the nasal septum across from the inferior turbinate in one healthy volunteer, showing typical temperature variation during the respiratory cycle for quiet breathing and deep breathing. (B) The range of temperature oscillations during the breathing cycle (i.e., the difference ΔT = Texp − Tinsp, where Texp is the end-expiratory temperature and Tinsp is the end-inspiratory temperature) was greater during deep breathing than during quiet breathing. The asterisk (*) denotes a statistically significant difference (p < 10−13).

FIGURE 3. Average nasal mucosal temperature in healthy subjects

Mean and standard deviation for end-inspiratory and end-expiratory temperatures for the left and right nasal cavities at measured sites, including deep breathing measurements.

FIGURE 4. The miniaturized thermocouple irritated the nasal mucosa in some subjects

(A) In a few cases, nasal mucosal temperature displayed a raising average trend during the 60 seconds of recording. (B) Comparison of the end-inspiratory temperature (Tinsp) in the first 3 breaths versus the last 3 breaths of the recording. A statistically significant rise in temperature was observed at the left vestibule (p = 0.0087).

FIGURE 5. Correlation between unilateral VAS scores with the difference between end-expiratory and end-inspiratory nasal mucosal temperatures (ΔT)exp-insp

Only (ΔT)exp-insp measured on the right vestibule had a statistically significant correlation with subjective nasal patency (Pearson r = −0.55; p = 0.0076).