0824 Can the interface utilized in continuous positive airway pressure therapy significantly alter the apnea-hypopnea index in certain patients with obstructive sleep apnea?

Abstract

Abstract Introduction Multiple studies and analyses have demonstrated that use of an oronasal interface for delivery of continuous positive airway pressure (CPAP) therapy can lead not only to higher pressure requirements, but also a higher residual apnea hypopnea Index (AHI) in patients with obstructive sleep apnea (OSA). Report of Cases: We record a 75-year-old man with severe OSA, AHI of 38, and treated with CPAP 16 cm water. On routine follow up, the residual AHI was 2.9, but he reported mouth-venting with nasal mask and stretched out the chinstrap. He was transitioned to an oronasal interface, and on subsequent follow-up his AHI was 19.6. The decision was made to change back to a nasal mask with a better-fitting chinstrap, which reduced his AHI to 4. To verify that the AHI recorded by the CPAP device was physiologic, the patient later used CPAP while wearing a home sleep apnea test (HSAT) utilizing peripheral arterial tonometry for 2 nights. On the night he used a nasal mask with a chinstrap, the AHI recorded on the CPAP was 1.4 and 3.9 on the HSAT. The following night, he wore the oronasal interface and the recorded AHI on CPAP was 31.6 and 18.5 on the HSAT. Conclusion Although oronasal masks are commonly used as an interface for CPAP, there is significant evidence that nasal delivery systems are more effective at controlling AHI in some individuals. Many studies show that oronasal masks not only correspond to an increase in AHI but also are associated with higher pressure requirements and a lower adherence compared to nasal interfaces. Imaging has shown greater retropalatal airway expansion when using a nasal interface compared to an oronasal device. Oronasal devices may also push the tongue posteriorly and cause increased occlusion of the airway. The consistent finding of worsening OSA control in the setting of oronasal masks has led many to consider CPAP with a nasal interface to be the gold standard for treating OSA. The clinician should therefore be mindful of these considerations when initiating or altering a CPAP interface. Support (If Any)