A technique to measure the ability of the human nose to warm and humidify air

Abstract

To assess the ability of the nose to warm and humidify inhaled air, we developed a nasopharyngeal probe and measured the temperature and humidity of air exiting the nasal cavity. We delivered cold, dry air (19-1 degrees C, <10% relative humidity) or hot, humid air (37 degrees C, >90% relative humidity) to the nose via a nasal mask at flow rates of 5, 10, and 20 l/min. We used a water gradient across the nose (water content in nasopharynx minus water content of delivered air) to assess nasal function. We studied the characteristics of nasal air conditioning in 22 asymptomatic, seasonally allergic subjects (out of their allergy season) and 11 nonallergic normal subjects. Inhalation of hot, humid air at increasingly higher flow rates had little effect on both the relative humidity and the temperature of air in the nasopharynx. In both groups, increasing the flow of cold, dry air lowered both the temperature and the water content of the inspired air measured in the nasopharynx, although the relative humidity remained at 100%. Water gradient values obtained during cold dry air challenges on separate days showed reproducibility in both allergic and nonallergic subjects. After exposure to cold, dry air, the water gradient was significantly lower in allergic than in nonallergic subjects (1,430 +/- 45 vs. 1,718 +/- 141 mg; P = 0.02), suggesting an impairment in their ability to warm and humidify inhaled air.

The relationship between water vapour saturation of inhaled air and nasal patency

“…In several investigations, a relative humidity of y90-100% in the nasopharynx could be observed [20,21]. These values are similar to the authors previous observations.…”

“…ROUADI et al [20] performed measurements in the nasopharynx during nasal breathing through only one nostril because the other nasal cavity was closed by the detection equipment. The particular features of the experimental setup in the current study are that the authors were able to measure relative humidity at defined intranasal detection sites, without interruption of physiological nasal breathing, without blocking one side of the nose and with registration of the respiratory cycle.…”

Expression of the Oligopeptide Permease Operon of Moraxella catarrhalis Is Regulated by Temperature and Nutrient Availability

“…The temperature of the human nasopharynx is variable, with measurements ranging from 37°C to 26°C (2,(17)(18)(19)(20)(21)(22). Temperature has an important impact on virulence factors and transcriptional regulation in M. catarrhalis (23)(24)(25).…”

“…Exacerbations of COPD related to the acquisition of M. catarrhalis and otitis media increase during the cooler winter months of the year (8,(53)(54)(55). The temperature of the nasopharynx, where M. catarrhalis first colonizes, is 34°C and decreases to 26°C upon exposure to colder temperatures in winter months in temperate climates (17)(18)(19)(20)(21)(22)(23)56). Cold shock increases the expression of the outer membrane protein UspA1, a known virulence factor, which is important for M. catarrhalis binding to host cells as well as immune evasion (23,25).…”

“…The gene cluster encodes two permeases, OppB and OppC; two ATPases, OppD and OppF; and a substrate binding protein, OppA (16). We hypothesized that this gene cluster was transcribed as an operon and that environmental factors, temperature and essential nutrients available as peptides, would alter the rate of transcription.The lower respiratory tract has a normal body temperature of 37°C, while the upper airways, specifically the nasopharynx, where M. catarrhalis first colonizes, ranges from 34°C at room temperature (25°C) down to 26°C after a short time of breathing air near 0°C, a temperature which many of the temperate climates throughout the world experience regularly throughout the winter months (2,(17)(18)(19)(20)(21)(22). Exposure to cold shock at 26°C has an important impact on virulence factors and transcriptional regulation in M. catarrhalis (23)(24)(25).…”