Oronasal vs Nasal Masks: The Impact of Mask Type on CPAP Requirement, Pharyngeal Critical Closing Pressure (Pcrit), and Upper Airway Cross-Sectional Areas in Patients With OSA

Shane A Landry; Dwayne L Mann; Richard Beare; Richard McIntyre; Caroline Beatty; Luke D J Thomson; Jinny Collet; Simon A Joosten; Garun S Hamilton; Bradley A Edwards

doi:10.1016/j.chest.2023.03.025

Oronasal vs Nasal Masks: The Impact of Mask Type on CPAP Requirement, Pharyngeal Critical Closing Pressure (P_crit), and Upper Airway Cross-Sectional Areas in Patients With OSA

Chest. 2023 Sep;164(3):747-756. doi: 10.1016/j.chest.2023.03.025. Epub 2023 Mar 27.

Authors

Affiliations

¹ Department of Physiology, Biomedical Discovery Institute, Monash University, Melbourne, VIC, Australia. Electronic address: shane.landry@monash.edu.
² School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, QLD, Australia.
³ National Centre for Healthy Ageing and Peninsula Clinical School, Monash University, Melbourne, VIC, Australia; Developmental Imaging, Murdoch Children's Research Institute, Melbourne, VIC, Australia.
⁴ Monash Biomedical Imaging, Monash University, Melbourne, VIC, Australia; Monash Imaging, Monash Health, Clayton, VIC, Australia.
⁵ Department of Physiology, Biomedical Discovery Institute, Monash University, Melbourne, VIC, Australia.
⁶ Monash Lung, Sleep, Allergy, and Immunity, Monash Health, Clayton, VIC, Australia; School of Clinical Sciences, Monash University, Melbourne, VIC, Australia; Monash Partners-Epworth, Clayton, VIC, Australia.
⁷ Department of Physiology, Biomedical Discovery Institute, Monash University, Melbourne, VIC, Australia; Turner Institute for Brain and Mental Health, Monash University, Melbourne, VIC, Australia.

PMID: 36990149
DOI: 10.1016/j.chest.2023.03.025

Abstract

Background: CPAP delivered via an oronasal mask is associated with lower adherence, higher residual apnea-hypopnea index (AHI), and increased CPAP therapeutic pressure compared with nasal masks. However, the mechanisms underlying the increased pressure requirements are not well understood.

Research question: How do oronasal masks affect upper airway anatomy and collapsibility?

Study design and methods: Fourteen patients with OSA underwent a sleep study with both a nasal and oronasal mask, each for one-half of the night (order randomized). CPAP was manually titrated to determine therapeutic pressure. Upper airway collapsibility was assessed using the pharyngeal critical closing pressure (P_crit) technique. Cine MRI was done to dynamically assess the cross-sectional area of the retroglossal and retropalatal airway throughout the respiratory cycle with each mask interface. Scans were repeated at 4 cm H₂O and at the nasal and oronasal therapeutic pressures.

Results: The oronasal mask was associated with higher therapeutic pressure requirements (ΔM ± SEM; +2.6 ± 0.5; P < .001) and higher P_crit (+2.4 ± 0.5 cm H₂O; P = .001) compared with the nasal mask. The change in therapeutic pressure between masks was strongly correlated with the change in P_crit (r² = 0.73; P = .003). Increasing CPAP increased both the retroglossal and retropalatal airway dimensions across both masks. After controlling for pressure and breath phase, the retropalatal cross-sectional area was moderately larger when using a nasal vs an oronasal mask (+17.2 mm²; 95% CI, 6.2-28.2, P < .001) while nasal breathing.

Interpretation: Oronasal masks are associated with a more collapsible airway than nasal masks, which likely contributes to the need for a higher therapeutic pressure.

Keywords: CPAP; collapsibility; oronasal masks; route of breathing; upper airway.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Continuous Positive Airway Pressure / methods
Humans
Larynx*
Masks
Respiration
Sleep Apnea, Obstructive* / therapy