Effects of Continuous Airway Pressure on the Ability to Heat and Humidify Air

Effects of Continuous Airway Pressure on the Ability to Heat and Humidify Air

We hypothesize that continuous positive pressure applied to the airway will decrease the ability of the nose to warm and humidify inspired air compared to zero or negative pressure.

We will use continuous positive airway pressure (CPAP), a device commonly used to treat patients with sleep apnea, to vary the pressure in the airway and determine if increased pressure decreases the ability to warm and humidify inspired air. If our hypothesis is correct, it may explain the reason why CPAP is poorly tolerated in patients with sleep apnea; i.e., less ability to warm and humidify air leading to more nasal mucosal irritation.

Inclusion Criteria:

1. Males and females between 18 and 55 years of age.
2. A clinical history suggestive of normal nose and upper airway, other than during a cold.
3. Willingness of the subject to participate in and complete the study, and the ability to understand the purpose of the trial.

Exclusion Criteria:

1. Physical sign or symptoms suggestive of renal, hepatic or cardiovascular disease.
2. Women of childbearing potential who are pregnant, trying to become pregnant or nursing a child.
3. Subjects treated with systemic steroids during the previous 30 days.
4. Subjects treated with topical (inhaled, intranasal or intraocular) steroids, Nasalcrom or Opticrom during the previous 15 days.
5. Subjects treated with oral antihistamine/decongestants during the previous seven days.
6. Subjects treated with topical (intranasal or intraocular) antihistamine/decongestants during the previous 3 days.
7. Subjects treated with immunotherapy.
8. Subjects on chronic anti-asthma medications.
9. Subjects with polyps in the nose or a significantly displaced septum.
10. Subjects who have incurred an upper respiratory tract infection within 14 days of the start of the study.