Effect of Changing Airway Pressure on the Ability of the Human Nose to Warm and Humidify Air

Abstract

Objectives:

Nasal continuous positive airway pressure (CPAP) treatment causes nasal symptoms that are believed to result from the drying effects of the air on the nasal mucosa, and these symptoms affect compliance with therapy. We hypothesized that the increased air pressure on the nasal mucosa caused by positive pressure from CPAP would decrease the ability of the nose to warm and humidify inspired air, explaining these symptoms.

Methods:

We performed a 4-way crossover trial using CPAP pressures of −5, 0, +5, and +10 cm H₂O in 10 subjects. The ability to warm and humidify inspired air was determined by measurement of the temperature of a fixed volume of cold, dry air entering and exiting the nostril and calculation of the amount of water supplied to the airstream by the nose.

Results:

The water content of air was unaffected at the pressures studied.

Conclusions:

The pressure of delivered CPAP does not affect the ability of the nose to warm and humidify inspired air.