It is best to introduce a patient to PAP therapy before the titration night in the sleep center. An education session should include a discussion of the rationale for the use of PAP therapy, side effects, mask fitting, and a hands-on demonstration with acclimatization; this is of particular importance for pediatric patients. Acclimating a patient to PAP therapy with positive feedback, patience, understanding, and empathy will help maximize future outcomes.

A well-fitting comfortable interface is critical for patient adherence. A patient who is uncomfortable with a mask for any reason will not use it regularly. For this reason, it is important that patients be included in the selection of their PAP interface. Among the considerations in selecting an appropriate interface are nasal patency, nasal or facial abnormalities, facial hair, whether the patient wears dentures or is missing teeth, full or shallow cheeks, hand-eye coordination, finger strength, impaired vision, manual dexterity and cognitive abilities, or a history of claustrophobia. There are several varieties of mask styles and sizes from which patients may choose. No single mask is ideal for all patients. The patient may select one type of mask at the beginning of the study that seems to fit comfortably and then during the study awaken and request a different mask. It is important to let patients know that there are alternatives if they have any issues during the study.

Humans are obligate nose breathers during wakefulness and mainly during sleep independent of sleep stage or position. However, many patients with sleep apnea will state that they are “mouth breathers” during sleep. Mouth breathing during sleep typically occurs when the airway collapses. This is caused by an increase in negative intrathoracic pressure, creating thoracic traction (also known as “thoracic tug”) that pulls the jawbone down, leading to mouth opening and an increased breathing effort. For this reason, a nasal mask should be the first mask of choice. A nasal mask is effective at decreasing mouth openings and prevents overuse of oronasal masks, increasing patient adherence (3).

There are several types of PAP interfaces, including nasal masks, nasal pillow, nasal cushion, oronasal (full-face) masks, oral masks, and total face masks.

When selecting the proper interface, there are several factors to consider: mask size and weight, strap types, the patient’s ability to move, and his or her preferred sleep position.

Nasal masks cover only the nose while resting on the upper lip, sides of the nose, and the nasal bridge.

Nasal pillows rest on the inside rim of the nostril. They are light and require minimal headgear. They are appropriate for patients who experience claustrophobia with a nasal mask and may work well for a patient with facial hair that prevents an adequate seal with other types of masks. However, the patient must be able to tolerate the inserts resting in the nostrils.

Nasal cushion masks have minimal contact under the nose cushions that prevent discomfort from or irritation in the nostril or on the bridge of the nose. With any type of nasal interface, there is a chance of air leaking from the patient’s mouth. A second option is a nasal mask with a chinstrap. A chinstrap is an elastic fabric band that applies upward pressure on the jaw to keep the mouth closed. These straps often connect to the nasal mask head straps.

Oronasal masks (full face) cover the nose and the mouth while resting on the chin, sides of the nose, and mouth and bridge of the nose. This interface is heavier than nasal masks or pillows but may be required in patients without a patent nasal airway.

Oral masks fit in the mouth between the lips and the teeth. They have a tongue stabilizer, which holds the tongue forward to prevent airway obstruction. Oral masks are not often used in the sleep center. Limitations with this interface include upper airway dryness, rainout associated with heated humidification, and air leakage from the nose.

Total face masks cover the entire face. It is an alternative for patients unable to obtain a good seal with other masks. It is preferably indicated for patients with facial deformities and those suffering from skin breakdown around the facial area.

Also available are combination devices that include an oral appliance and PAP interface (3).

Most manufacturers provide a size guide for sleep centers to use to obtain an accurate mask fit. Using the guide provides a good starting point for finding the right mask for the patient. However, faces and noses are all different, and sometimes it is necessary to try more than one size or type of mask to get an optimal fit. Also, mask sizes differ between manufacturers; a medium-wide mask from one manufacturer may be quite different than a medium-wide mask from another.

Upper airway resistance and the likelihood of developing OSA is higher when breathing through the mouth than when breathing through the nose. The oronasal (full-face) mask applies positive pressure equally to the nasopharyngeal and oropharyngeal compartments, thus eliminating the pressure gradient that allows the soft palate and tongue to relax and cause an obstruction. Higher PAPs are required, and leaks are significantly higher in patients wearing oronasal (full-face) mask than nasal mask interfaces. Additionally, oronasal (full-face) masks reflect a lower PAP adherence rate. Sleep efficiency, slow-wave sleep, and rapid eye movement sleep are greater during titration with a nasal mask. Patients wearing the nasal pillows mask and those wearing the nasal masks have both reported improved Epworth Sleepiness Scale score and quality of life. The nasal mask and the nasal pillows are equally as effective when treating patients with OSA requiring high pressures (3). Oronasal masks are associated with higher PAPs, higher residual apnea-hypopnea index (AHI), and poorer adherence than nasal masks. Therefore, patients using oronasal (full-face) masks should be closely monitored. Nasal interfaces should always be the first choice. There is evidence that the prolonged use of nasal PAP reduces mouth opening and oral breathing. Therefore, even patients with OSA who claim to be mouth breathers could be initiated with nasal masks. Another clinical implication is that sleep studies for PAP titration must be performed with the same type of mask that the patient will use at home. It is highly suggested that nasal masks or nasal pillows be used instead of oronasal (full-face) masks in OSA patients unless there is a clear indication otherwise (4, 5).