Air leaks from the mouth whenever the mouth is opened during CPAP therapy. This occurs for many reasons, but a very common one is due to nasal irritation from the CPAP airflow.
The correlation between the lack of humidification and mouth leaks is a topic being heavily researched. Studies are now being conducted on the hypothesis that a large amount of mouth leakage is caused by the following cycle:
- CPAP therapy is used with ineffective or no humidification.
- The nasal membranes are unable to adequately condition the increased airflow and after a few minutes the airway and nasal passages become dry.
- To remedy the dryness and obtain moisture, the body uses the mouth to breathe.
- CPAP air follows the path of least resistance and leaks out of the open mouth.
- The air leaking through the mouth causes more dryness.
- Patient wakes up feeling tired with significant dryness in mouth and dry, swollen nasal passages.
The answer to this cycle is
humidification. If the mouth continues to open during sleep, a
chinstrap may be needed to hold the jaw up so that the mouth can close. If mouth breathing continues, a
full face mask that covers the nose and mouth is indicated.