Humidification in CPAP Therapy

The following information is provided by Fisher & Paykel Healthcare

CPAP Therapy Potential Problems

If typical room air is at 20ºC containing about 10 mg H2O per litre of gas, and the body supplies the remaining heat and moisture required for efficient gas exchange, what happens during CPAP therapy?

The nasal airway is unable to maintain sufficient warmth and humidity for the increased gas flow of CPAP therapy. As a result, the patient's airways lose moisture, and they will eventually exhibit symptoms consistent with upper airway drying and inflammation, such as:

• Dry nose
• Breakdown of the soft tissue around the nares
• Dry throat
• Bleeding nose
• Headache
• Dry cracked lips
• Chest discomfort
• Infections of the nose, throat and sinuses

Such patients find speech and clearing of their dry nose difficult. This can often result in the patient being less compliant with the therapy.

Maximum compliance is achieved by maximizing patient comfort. The easiest and most successful way to increase patient comfort is by using heated humidification.

A group at the Western Pennsylvania Hospital conducted a study in which it randomized OSA patients using CPAP to receive either heated humidification, cool passover or no humidity (4). 19 patients in each arm of the study were covertly monitored for CPAP use.

By the conclusion of the study, patients with heated humidification were more compliant with their CPAP therapy and experienced less drying of the airway passages.

Patients with heated humidification complied with their CPAP therapy on average 42 minutes longer per night and experienced less drying of the nasal passages than those with cold passover humidification. As CPAP is such an intrusive therapy, patient compliance is a very important issue. This graph shows that heated humidification improves compliance more than cool passover (4).

By the end of month 3, eight of the original nineteen patients (42%) without humidity discontinued therapy vs two patients (10%) in the heated humidified arm and three patients (15%) in the cool passover arm. Of the eight patients who dropped out of the group with no humidity, 5 complained of excessive drying of the nasal passages, mouth and throat, 1 developed nose bleeds, 1 could not breathe due to congestion and 1 gave no specific reason. Of the subjects who dropped out of the cool passover group, 2 complained of unacceptable nasal congestion and rhinorrhea and 1 experienced excessive drying of the nose and throat. In the heated humidification group, 1 discontinued therapy due to hospitalization for an acute myocardial infarction and 1 disliked all masks that were offered after the initiation of therapy.

Previous | Next

• The Role Of Humidification in CPAP Therapy
• What is Humidity?
• How the Human Body Humidifies Air
• CPAP Therapy Potential Problems
• Mouth leak and the Vicious Cycle
• Increase in Nasal Resistance
• Compliance With CPAP Therapy
• Frequently Asked Questions
• References