title: Effect of changing airway pressure on the ability of the human nose to warm and humidify air.
abstract: OBJECTIVE
  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.
authors.affiliation: Department of Surgery, Section of Otolaryngology-Head and Neck Surgery, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Asli
authors.initials: A
authors.lastname: Sahin-Yilmaz
authors.forename: Fuad M
authors.initials: FM
authors.lastname: Baroody
authors.forename: Marcy
authors.initials: M
authors.lastname: DeTineo
authors.forename: Georgina
authors.initials: G
authors.lastname: Cuttance
authors.forename: Doug
authors.initials: D
authors.lastname: Makinson
authors.forename: Jayant M
authors.initials: JM
authors.lastname: Pinto
authors.forename: Edward T
authors.initials: ET
authors.lastname: Naureckas
authors.forename: Robert M
authors.initials: RM
authors.lastname: Naclerio
mesh_terms: D000328:Adult; D000388:Air; D045422:Continuous Positive Airway Pressure; D018592:Cross-Over Studies; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D008297:Male; D009666:Nose / Q000502:physiology*; D011446:Prospective Studies