Respiratory specialists have issued an alert over portable oxygen concentrators (POCs) that are being sold online, warning that these products don’t work as well as prescription devices – if they work at all.
They said 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 what they see online may not provide what they need, if they medically need supplemental oxygen,” Dr Richard Casaburi of Harbour UCLA Medical Centre in California told MedPage Today.
Casaburi was the lead author of a recent paper published in Respiratory Care comparing the performance of OTC and prescription devices.
“We call them, instead of oxygen concentrators, oxygen ‘non-centrators’,” he added.
A portable oxygen concentrator is a compact version of the stationary machine used at home by patients with chronic lung disease. 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. In the US, out of pocket, they can cost more than $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 POC descriptions with photos of the machines used by young women 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.
In Casaburi and the team’s study, only one of the three OTC POCs tested produced meaningful increases in end-tidal oxygen tension (PETO2), which was used as a surrogate for alveolar partial pressure oxygen (PO2), the amount of oxygen dissolved in the blood.
But even that one provided less PETO2 than the FDA-approved prescription version, they reported.
Dr Laura Spece, 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 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, editor-in-chief of 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”.
“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 just 15m.
“What if we put a tether on your prosthetic (leg), that you could only get 15m away from the house with it? So when you got halfway to the postbox, you had to unsnap it and then hop out to get your mail?”
Study details
Evaluation of over-the-counter portable oxygen concentrators utilising a metabolic simulator
Richard Casaburi, Michael Hess, Janos Porszasz, William Clark, Ryan Diesem, Ruth Tal-Singer and Carrie Ferguson.
Published in Respiratory Care on 1 April 2023.
Abstract
Background
Supplemental oxygen is designed to raise alveolar PO2 to facilitate diffusion into arterial blood. Oxygen is generally delivered by nasal cannula either by continuous or pulsatile flow. Battery-powered portable oxygen concentrators (POCs) facilitate ambulation in patients experiencing exertional hypoxemia. In the United States, the Food and Drug Administration (FDA) clears these devices to be sold by physician prescription. Recently, however, lower-cost devices described as POCs have been advertised by online retailers. These devices lack FDA clearance and are obtained over the counter (OTC) without prescription. This study determined whether a selected group of OTC POCs have oxygen delivery characteristics suitable for use by hypoxemic patients.
Methods
A metabolic simulator, capable of simulating a range of metabolic rates and minute ventilations, determined effects of oxygen supplementation delivered by a variety of devices on alveolar PO2. Devices tested included 3 OTC POCs, an FDA-cleared POC, and continuous-flow oxygen from a compressed oxygen cylinder. End-tidal PETO2, a surrogate of alveolar PO2, was determined at each of each device’s flow settings at 3 metabolic rates.
Results
Continuous-flow tank oxygen yielded a linear PETO2 increase as flow increased, with progressively lower slope of increase for higher metabolic rate. The prescription POC device yielded similar PETO2 elevations, though with somewhat smaller elevations in pulse-dose operation. One OTC POC was only technically portable (no on-board battery); it provided only modest PETO2 elevation that failed to increase as flow setting was incremented. A second OTC POC produced only minimal PETO2 elevation. A third OTC POC, a pulsed-dose device, produced meaningful PETO2 increases, though not as great as the prescription device.
Conclusions
Only one of 3 OTC POCs tested was potentially of use by patients requiring ambulatory oxygen. Physicians and respiratory therapists should inform patients requiring portable oxygen that OTC devices may not meet their oxygenation requirements.
MedPage Today article – Doctors Warn About Portable Oxygen Machines Sold Online (Open access)
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