Impact of Exclusive Mouth Route and lateral position on the efficacy of oronasal CPAP to treat Obstructive Sleep Apnea in Patients with Obstructive Sleep Apnea Adapted to Oronasal Mask.

Abstract

Background: Oronasal masks are widely used for treating OSA with CPAP. However, oronasal CPAP is associated with lower effectiveness and lower adherence than nasal CPAP.

Research question: What is the impact of oral route and lateral position in patients well adapted to oronasal CPAP? Can these patients be switched to nasal CPAP?

Study design and methods: Patients with OSA on oronasal CPAP underwent 2 CPAP polysomnography (PSG) titrations in random order using an oronasal mask with 2 independent sealed compartments connected to two separate pneumotachographs. One study was done with the nasal and oral compartments opened and the other study with only the oral compartment opened. CPAP titration was done in the supine and lateral position. Finally, the patients were offered a nasal mask. A third PSG was performed using nasal CPAP.

Results: Twenty OSA patients (baseline AHI: 52 ± 21 events/h) adapted to oronasal CPAP were studied. Most patients (75%) were oronasal breathers on optimal CPAP. Oral CPAP was less effective to treat OSA than oronasal CPAP, evidenced by a higher residual AHI (2 (1 - 6.0) vs 12.5 (1.8 - 28.3); P = 0.003), despite a significantly higher CPAP level, (10 (9 - 10) vs 11 (10 - 12) cmH20; P = 0.003). The residual AHI was significantly lower in the lateral position for both oronasal and oral CPAP. Finally, patients (75%) agreed to change and preferred to continue on nasal mask, which resulted in lower CPAP and better OSA control.

Interpretation: The effectiveness of oronasal CPAP to abolish OSA is significantly decreased when patients are required to breathe exclusively through the mouth. Oronasal CPAP efficacy is significantly better in the lateral position. The transition to nasal mask results in higher CPAP effectiveness to treat OSA.