Acceptable Upper Limit of Air Leak via CPAP Mask

Manufacturer-Specific Leak Thresholds

The American Thoracic Society guidelines provide specific large leak thresholds that differ by manufacturer, with ResMed devices defining excessive unintentional leak as >24 L/min with nasal interface and >36 L/min with full-face interface (95th percentile leak) 1, 2, 3
Fisher & Paykel sets the threshold for total leak (including mask and exhaust flow) at >60 L/min 1, 2, 3
DeVilbiss Healthcare IntelliPAP records high leak flow time when leak exceeds 95 L/min 1, 2, 3
Philips Respironics uses a preset "flow vs. pressure" curve rather than a fixed threshold, as leak varies with pressure level 1, 2, 3

Excessive leak compromises CPAP effectiveness and should prompt immediate mask adjustment, according to the American Academy of Sleep Medicine 4
The American Academy of Sleep Medicine recommends identifying leak type, distinguishing between intentional leak, mouth leak, and mask leak, and performing immediate interventions such as refit or readjustment of mask for mask leak 4

The American Academy of Sleep Medicine advises against relying on fixed leak values alone, emphasizing the importance of clinical judgment based on sudden leak changes and manufacturer specifications 4
Intentional leak increases with pressure, making absolute leak values pressure-dependent, as noted by the American Academy of Sleep Medicine 4

For patients with overlap syndrome (OSA + COPD) or those requiring BiPAP, the same leak thresholds apply, but vigilance is heightened as leak can compromise ventilation, according to guidelines from the American Academy of Sleep Medicine and other sources 5, 6, 7