Clinicians should look out for signs that a full face mask is too small or too large and should help patients with maintaining the mask to keep it “just right.”

Much like the story of Goldilocks, some full face CPAP masks will be too large, some too small, and some just right for any given obstructive sleep apnea (OSA) patient. Manufacturers aim to create full face masks for a wide variety of patients so everyone can find a well-fitting mask.

Offering a Range of Sizes and Designs

“Mask sizing is definitely not an exact science because sizing is not just about mask dimensions, but also about patient expectations around fit,” says Subbarao Potharaju, director of marketing, homecare at Fisher & Paykel Healthcare Inc. “For example, just as some people like to wear tight jeans and others like loose jeans, there is a spectrum of patients related to a preference for a loose mask fit to a preference for a tight fit. Further, patients sleep in many different ways, which affects sizing. Some people are naturally still sleepers and others are restless sleepers, and there are many permutations in between. A good CPAP mask adapts to the patient’s face and adapts as the patient moves.”

Some mask makers use big data to determine what the size options should be. Susie Justus, LVN, clinical specialist at ResMed, explains ResMed’s process. “ResMed actually measured thousands of faces all across the globe,” Justus says, and then averaged those measurements to come up with sizes to “accommodate the vast majority of patients while still helping HMEs [home medical equipment providers] and sleep labs efficiently manage their inventory.” Philips similarly analyzed its database of 3D facial scans, which includes thousands of scans of OSA patients, to determine the range of facial sizes that a mask needs to accommodate. “We conduct engineering design analysis and extensive prototype trials with patients to validate that the sizes we offer will fit the expected range of facial sizes and shapes,” says Kevin Coldren, director of marketing, patient interface and sleep diagnostics at Philips.

Kelly Rudolph, president of Hans Rudolph Inc, says the company opted to create 5 sizes—petite, extra small, small, medium, and large—for each full face mask to ensure that it fits all face sizes, shapes, and types. “Most faces vary in size, shape, and geometry,” he says.

Angela Giudice, RPSGT, director of clinical sales and education at 3B Medical Inc, says, “We offer two styles of full face masks, one traditional and one without a forehead brace. Both styles are available in small, medium, and large. However, the frames are proportioned differently on even those sizes, making the line flexible for the vast majority of patients.”

Clinician Mistakes Happen

The biggest mistake Coldren sees clinicians make is not using sizing templates. He says, “In the past, clinicians could simply eyeball the fit because most mask sizing was based on nose width. As our knowledge has increased, we have learned that we need to consider much more than nose width to design better fitting and more comfortable masks.” For example, the cushions for Philips’ DreamWear full face mask take into account upper lip curvature—a measurement that clinicians can’t accurately estimate without a template.

Rudolph also says a size fitting gauge is key, which includes clear labels as to where and how to place the gauge on the patient’s face to determine mask sizing. “The clinicians have a tough job as every patient has a different shaped face in both length and girth,” he says. “Our masks are made out of one soft piece of flexible material that helps give the clinician and patient some flexibility when fitting the masks.” But, Rudolph explains, if clinicians don’t use the plastic sizing gauge or print out an image of the sizing gauge on paper without following printer setting instructions, then they can size a patient incorrectly.

3B’s Giudice adds, “Not all masks are appropriate for all patients, even when measured correctly. Sometimes muscle, teeth, facial hair, and bone structure will make more of a fit difference than one would think. As a clinician myself, I always say the best mask for the patient is the one they will use. I will accept small issues like a little leak if it means my patient is comfortable and compliant.”

Too Small, Too Large?

Patients may not be able to articulate if a mask isn’t a proper fit, especially those who are starting PAP therapy for the first time. But they may communicate the telltale signs in other ways.

“Masks that are too small can often create pressure points on the nose or upper lip,” Coldren adds. “Depending on the mask design, there may also be visible occlusion of the nostrils or mouth if the cushion is too small.”

Hans Rudolph masks have chin cups that allow patients to open and close their mouths. “If that is riding up high and near the patient’s mouth, it is likely too small for them,” Rudolph says. Signs the mask is too big? “The top of the mask should be resting right below the bridge of the nose and not obstructing the patient’s view,” says Rudolph. “If the mask is sitting higher than that and making it difficult for the patient to see, they are more than likely wearing a mask that is too large.”

Justus says a mask is likely too large if the cushion is approaching the same height as the user’s eyebrows, or if the cushion hinges closer to the chin instead of sitting in the crevice around the upper chin. The mask may be too small, she says, if it’s touching the lower lip or even the teeth, or if the top part of the mask is pinching the nares (nostrils) or nasal bridge.

Maintaining a Good Fit

Once a PAP user has a full-face mask that fits properly, Justus offers these tips for clinicians and patients on keeping the fit “just right.”

  • Magnets or marker. If a patient’s mask has magnets, suggest using those to put on and remove their mask, leaving the headgear straps in the same place. If they don’t have magnets, suggest they mark the sides of their headgear straps with a permanent marker (so they don’t have to guess each time they put it on).
  • Regular cleaning. Patients should wash their masks and headgear as recommended by the manufacturer, which helps maintain the integrity of the mask’s materials, particularly the silicone cushions.
  • Scheduled resupply. Encourage patients to replace masks on a scheduled basis. Cushions may look fine, but daily use and unwashed skin oils can start to jeopardize the mask’s optimal seal.

Potharaju adds, “One of the important aspects of maintaining the performance of the mask is to make it intuitive and easy for the patient to assemble all parts of the mask into the original settings after cleaning.”

Providing patients with appropriately fitting full face masks is of paramount importance for patients to be comfortable during PAP therapy. Through identifying issues with size and helping maintain proper fit, manufacturers and clinicians alike can help patients avoid a frustrating trial-and-error period.

Dillon Stickle is associate editor of Sleep Review.