As sleep professionals and patients await repaired or replaced devices, many turn to in-line filters that are readily available over the internet. But are the filters effective against foam particulates and off-gassing?
By Lisa Spear
The gentle hum of his positive airway pressure machine never bothered sleep apnea patient Jeffrey Scott Richards. The device sits by the 43-year-old’s bedside every night in his Texas home, like a trusted friend. He never questioned its safety. After all, he thought, his physician prescribed the machine to keep him healthy.
After about a year of using his DreamStation, the medical device company that sells his device, Philips Respironics, recalled the machine, and millions like it that are used to treat sleep apnea. The company declared that a black piece of foam on the inside of the machines that is used to mitigate noise and vibration from the motor could be breaking down, exposing users to particulates and potentially toxic or carcinogenic chemicals.
Richards’ physician would not advise him on what to do, and Philips gave him no word on how long it will take to repair or replace the device, so Richards decided to continue using the machine, too fearful of going back to the fatigue, heart palpitations, and anxiety that he experienced before his sleep apnea was treated.
“Well, really, you have two options: you could get cancer, or you could die in your sleep, I will probably go with cancer,” Richards says. “I am going to roll the dice and use the CPAP.”
Now, like so many others, Richards turned to the Internet to find an interim solution. Many people in his sleep apnea support group on Facebook, too fatigued during the day or sick with heart conditions to consider stopping CPAP use, turned to in-line filters to mitigate risk while they continue to use their recalled machines.
Richards ordered a CPAP filter off of Amazon, going with the one that had some of the best customer reviews. The CPAP filters that he ordered are often called “in-line” filters because they are usually placed directly inside the tubing that feeds air from inside the positive airway pressure machine to the person’s mouth or nose.
These filters are easy to obtain from online retailers, but there is no evidence they are effective at removing gaseous chemicals. Indeed, the FDA has released a statement stating that in-line filters will not protect consumers from chemicals produced by the polyester-based polyurethane foam inside the recalled Philips machines. It further states, “The FDA does not have evidence of the safety and effectiveness of a filter for mitigating the foam risks, and the FDA’s evaluation is ongoing.”
The in-line filters, Philips says, may trap some foam particles and prevent them from irritating the patients’ airways, but questions remain on just how effective they are for that purpose.
“Product specifications commonly do not always clearly elaborate on performance, such as the particle diameter at which the filter will efficiently remove particles, though they may make more general statements about filtration,” explains Shannon Sullivan, MD, the American Academy of Sleep Medicine’s (AASM) public safety committee vice chair in an email to Sleep Review.
If a company is claiming that filters are N95, meaning they filter at least 95% of very small particles less than .3 microns in size, then they are regulated by the FDA and have to submit data to support their claims. But few, if any, companies that make in-line CPAP filters make such specific claims about what their products are capable of filtering, explains Kristen Hedger Archbold, RN, PhD, co-founder and CEO of Azimuth Sleep Solutions, which produces a N99-rated CPAP mask (not in-line) filter called the PortPatch.
“I think the message is: buyer beware,” says Archbold.
Still, many sleep specialists, unsure of what to do and hoping to prevent some amount of harm to their patients, recommend the in-line filters as a way to cope while they wait for Philips’ next steps. During a recent AASM panel, the moderator mentioned receiving several questions from sleep labs about whether they should consider outfitting their CPAPs used in titration studies with filters.
A sleep specialist at Johns Hopkins Center for Sleep, Sara Elizabeth Benjamin, MD, mentioned that the lab where she works is outfitting its CPAP machines with filters, while making patients aware of the risk by way of a consent form.
But other sleep specialists do not favor their use. These filters will not help filter gases out, so I would not recommend them,” explains Akhil Raghuram, MD, medical director of the Vancouver Sleep Center in Portland, Ore.
In an email to Sleep Review, Philips representative Mario Fante said, “While filters may potentially provide protection from foam degradation, there are design, engineering, and other factors that would need to be addressed to make this use effective.”
The in-line filters, Fante said, should only be used for 1 to 2 days in a clinical setting. Use beyond this period is considered off-label use.
Sullivan cautions that in-line filters can also cause problems with certain devices, including CPAP, APAP, or bilevel devices, which are also the most commonly used devices.
“These devices have design characteristics which may present issues for the use of in-line filters,” says Sullivan, a sleep specialist at Stanford Center for Sleep Sciences and Medicine in California.
Sullivan explains that if someone were to decide to use an in-line filter, it might fit between the device and its tubing. On certain PAP devices, this would interfere with the heated tubing mechanism. Another place the filter might be fitted is between the hose/tubing and the mask, which would be bulky.
Also, heated humidifiers, often used with CPAP, can cause water to collect in the filter chamber, which may clog the filter. The filters may also impact therapy by affecting auto-sensing and/or by adding resistance to airflow, according to Sullivan.
Nevertheless, patients like Richards feel as if they have few options. Some are paying out-of-pocket for new machines. Richards has ordered a ResMed device but doesn’t know when it will arrive. Until then, he says, he has started using an in-line filter and a nagging sore throat that he has had since starting his therapy has dissipated.
“The biggest thing is: I just need to be able to function throughout my day,” says Richards. “Being able to function and being able to do the things that I enjoy to do is important, if that means I have to inhale cancer gas all night long, I will do it until this thing is over.”
Lisa Spear is associate editor of Sleep Review.