A leaking mask makes noise, dries your eyes and mouth, and can wake you or your partner. Large leaks can also affect how well your therapy works and how accurately the machine reports it: the AirSense 11 user guide notes its displayed results “may be inaccurate in the presence of leaks” (ResMed AirSense 11 user guide).
How much leak is too much?
Every CPAP mask has intentional vents, so some airflow out of the mask is normal. The question is unintentional leak, around the cushion or through your mouth.
ResMed’s troubleshooting guide for care providers states: “High leak is anything > 95% pressure of 24 liters/min or more” (ResMed troubleshooting guide). In practice, if the 95th-percentile leak on a ResMed machine is 24 L/min or above, your provider will treat it as high. Other brands report leak differently, so use your own machine’s documentation.
Step-by-step fixes
| Step | What to do | Source |
|---|---|---|
| 1 | Put the mask on with the machine running, then adjust the straps until you can’t hear air blowing out of the mask | ATS |
| 2 | Run your machine’s mask fit check (ResMed: More → Mask Fit) | ResMed |
| 3 | Don’t over-tighten. Readjust, and consider a new cushion or mask instead | ResMed, AASM |
| 4 | Clean the cushion daily, as your mask user guide describes | AASM, ResMed |
| 5 | Lay the tube over your chest under a blanket, or use a tube holder, so it doesn’t pull on the mask | ATS |
| 6 | For leaks that depend on position: CPAP pillow with cut-outs, raise the head of the bed, or a different mask style | AASM, ATS, ResMed |
| 7 | Check the cushion, frame and tube for tears, cracks or discoloration | ResMed |
| 8 | Mouth leak with a nasal mask: chin strap or full face mask | ResMed, AASM |
| 9 | Still leaking: get refitted, or switch mask size or type | ATS, ResMed |
Sources: American Thoracic Society tip sheet, AASM PAP troubleshooting FAQ, ResMed troubleshooting guide, ResMed AirSense 11 user guide.
Check your setup too
Not every high-leak alert comes from the mask. The AirSense 11 guide lists “High leak detected” messages caused by a humidifier tub or side cover that isn’t inserted properly, or air tubing that isn’t firmly connected at both ends (ResMed AirSense 11 user guide). Reseat the tub and check both ends of the tube before you blame the mask.
Leaks into your eyes
The AASM says that if a nasal mask sits too high on the bridge of your nose, it can direct air into your eyes. Adjust the pads and straps, or try nasal pillows, which may also allow more movement during the night (AASM PAP troubleshooting FAQ).
When it’s time for a different mask
ResMed’s guide suggests trying a different mask when leaks persist after checking headgear, cushion size and cleaning. For mouth leaks, that means a full face mask such as the AirFit F20. For noise or minimal-contact needs, it suggests options such as the AirFit P10, N30i or F30. Our CPAP mask guide compares them with US prices. ResMed also warns that the AirFit F20, F30 and AirTouch F20 contain magnets that may interfere with some implants or medical devices. Check the mask’s user guide if you have one.
Medicare’s usual maximum is 1 mask every 3 months and cushions monthly or twice monthly, depending on type (replacement schedule).
Verdict
Refit the mask with the machine running, loosen rather than tighten the straps, and keep the tube from pulling on it. Check the tub and tube connections, then replace a worn cushion. If your machine still reports high leak (24 L/min or more at the 95th percentile on ResMed), get refitted or change mask style. Mouth leaks call for a chin strap or a full face mask; see dry mouth.