麻豆传媒

Almost anything is for sale on Amazon -- even portable oxygen concentrators (POCs), which usually require a prescription to obtain.

But respiratory medicine specialists are warning that these over-the-counter (OTC) devices perform poorly compared with their FDA-approved counterparts, and that patients should avoid them.

"Healthcare providers should warn patients: that device they see online may not provide what they need, if they medically need supplemental oxygen," Richard Casaburi, MD, PhD, of Harbor UCLA Medical Center in Torrance, California, told 麻豆传媒. Casaburi was the lead author of a published in Respiratory Care comparing the performance of OTC and prescription devices.

"We call them, instead of oxygen concentrators, oxygen 'noncentrators,'" he added.

A portable oxygen concentrator is a compact version of the stationary machine that patients with chronic lung disease would use at home. Both take in air from the environment and concentrate the oxygen, delivering it via nasal cannula in either a steady stream or pulses. POCs, however, are battery operated and can be carried in a shoulder bag or backpack, enabling users to visit family, see a movie, or eat at a restaurant.

Several manufacturers make FDA-approved POCs that are only available by prescription and that can be covered by insurance. Out of pocket, they can cost well over $2,000. OTC POCs, on the other hand, can cost about $400 to $600.

Their manufacturers are careful not to market them explicitly as medical devices, skirting both FDA and retailer rules. A search on Amazon reveals of the machines used by a young woman resting after a workout, or a smiling pregnant mother sitting on the floor of her living room.

Casaburi said they may be a tempting option for lung disease patients who don't have the prescription version.

FDA-approved devices are "sometimes covered by insurance and sometimes they're not," Casaburi told 麻豆传媒. "So there's patients who are out there thinking, 'Gee, that's a lot of money. Can I get by with something less expensive?'"

In Casaburi and team's study, only one of the three OTC POCs tested produced meaningful increases in end-tidal oxygen tension (P_ETO2), which was used as a surrogate for alveolar partial pressure oxygen (P_O2), the amount of oxygen dissolved in the blood. But even that one provided less P_ETO2 than the FDA-approved prescription version, Casaburi and co-authors reported.

Laura Spece, MD, a pulmonologist with the VA Puget Sound Health Care System in Washington who was not involved in the study, said that FDA-cleared prescription POCs are carefully calibrated to a patient's specific needs during a doctor visit, further increasing the risks of buying over-the-counter.

Once the patient has the device, she said, "we then figure out how to dial up the oxygen so that they can maintain a safe oxygen level while they walk," and do the same at other levels of exertion. "And so that prescription is tailored to them."

Richard Branson, MSc, RRT, the editor-in-chief of Respiratory Care, the journal of the American Association for Respiratory Care, said that patients "require and deserve to have devices that improve their quality of life. In chronic obstructive pulmonary disease, oxygen therapy increases the duration of your life and improves the quality of your life."

In a conversation monitored by a public relations representative, Branson said access to FDA-approved devices is a bigger problem. "CMS has been treating home oxygen therapy like it's a business, which it is, but it reduces the flexibility for home oxygen therapy patients to control costs." Traditional Medicare can help pay for the rental of both stationary and portable oxygen concentrators if they're prescribed and the patient meets certain medical criteria. Traditional Medicare will not cover the purchase of POCs, though some Medicare Advantage plans might.

"Patients who have chronic lung disease basically have lost a portion of their lung function, but they're tethered to a device that allows them to travel 50 feet," Branson said of home oxygen devices. "What if we put a tether on your prosthetic [leg], that you could only get 50 feet away from the house with it? So when you got halfway to the mailbox, you had to unsnap it and then hop out to get your mail?"

Casaburi and Branson both disclosed financial relationships with Inogen, a leading maker of FDA-approved POCs. But even Spece, who reported no such disclosures, agreed that OTC POCs are, in general, problematic.

Spece noted that there are differences of opinion in how much of a benefit portable oxygen provides to some patients. For example, some patients with moderate hypoxemia from chronic obstructive pulmonary disease (COPD) may not see much of a long-term benefit from using supplemental oxygen, according to a .

"We should use it when we need to use it, but we shouldn't overuse it," she said.

She said her patients are usually able to get POCs covered by insurance when they need it, although it may not always be their preferred brand of FDA-approved POC.

Insurance coverage can vary widely, however, and Spece said patients who want the extra support of an OTC device when leaving the house may still turn to cheaper OTC devices -- and end up wasting their money.

"It's anxiety-producing to have lung disease and to know that your oxygen levels may not perform perfectly ... so it could be a real panacea to think, 'Well, but I have this [portable] oxygen device ... if things get really bad,'" she said. "But, what they're actually purchasing isn't something that works."

Correction: Traditional Medicare does not cover the purchase of a portable oxygen device, as stated in a previous version of this story, but it may help pay for the rental of a stationery and/or a portable oxygen concentrator.

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