What is a factor that can make nasal masks less effective?

Nasal obstruction significantly impacts the effectiveness of nasal masks used in noninvasive mechanical ventilation. When there is any blockage in the nasal passages, such as from congestion or anatomical variations, it restricts airflow and hampers the patient's ability to breathe effectively through the nose. Consequently, this can lead to inadequate ventilation and increased work of breathing, as the patient may not receive the full benefit of the positive pressure delivered by the nasal mask.

In contrast, improved facial fitting, proper sizing, and higher airflow rates generally enhance the functionality and comfort of nasal masks. A good fit ensures minimal air leakage, proper sizing helps in achieving the right seal and comfort, and higher airflow rates can improve the delivery of oxygen. However, any nasal obstruction negates these advantages, making it a critical factor to consider in managing patients on noninvasive ventilation.