Humidification in CPAP Therapy

The following information is provided by Fisher & Paykel Healthcare

Increase in Nasal Resistance

In 1995, the American Thoracic Society published a paper by Richards et al entitled Mouth Leak With Nasal Continuous Positive Airway Pressure Increases Nasal Airway Resistance (2). This paper revealed some significant facts:

• Mouth leaks cause unidirectional (1-way) airflow past the nasal membranes, which causes an increase in nasal airway resistance (NAR).
• Heated humidification reduces NAR by supplying the required humidity to the air that the nose is unable to supply.

Patients were using nasal CPAP at 12cm H 2 O with a calibrated mouth leak* of 50 L/min for 10 mins. This graph compares NAR after the mouth leak has taken place. Every subject included in the study exhibited an increase in NAR following mouth leak.

*= Mouth leak was simulated by mouth breathing

A mouth leak was simulated while the patient was on CPAP with room air, cold passover humidification and heated humidification. Cold passover humidification caused little change in the patients' response to the challenge, but the heated humidifier minimized the increase in NAR and reduced recovery time.

• 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

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