Non-prescription portable oxygen concentrators may not be ‘clinically useful’
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Key takeaways:
- One out of three non-prescription portable oxygen concentrators was deemed “clinically useful.”
- An FDA-cleared portable oxygen concentrator showed the best performance.
For patients who need ambulatory oxygen, over-the-counter portable oxygen concentrators sold online that do not require a prescription may not be helpful, according to study results published in Respiratory Care.
“My colleagues at the COPD Foundation and I were concerned that patients with COPD who require ambulatory oxygen might purchase OTC (not requiring a prescription) oxygen concentrators, believing that these devices would be appropriate for their use,” Richard Casaburi, PhD, MD, associate chief for research in the division of respiratory and critical care physiology and medicine at Harbor-UCLA Medical Center and professor of medicine at David Geffen School of Medicine at UCLA, told Healio. “However, only one of three of the OTC portable concentrators we tested was potentially of use by patients requiring ambulatory oxygen.”
In this study, Casaburi and colleagues evaluated three OTC portable oxygen concentrators not cleared by the FDA to see if they might be appropriate for patients with hypoxemia.
By using a metabolic simulator that mimics metabolic rates and minute ventilations that might be seen in patients with COPD, researchers assessed oxygen supplementation on alveolar oxygen partial pressure from these devices compared with one FDA-cleared portable oxygen concentrator and a compressed oxygen tank.
Each of the three devices had varying oxygen flow settings. For example, OTC1 had continuous flow from 1 L to 7 L per minute in 1 L per minute increments, whereas OTC2 had single flow of3 L per minute and OTC3 had pulse-dose flow settings that ranged from 1 to 5.
In comparison, the FDA-cleared device had continuous flow at 1 L or 2 L per minute and pulse-dose flow settings that ranged from 1 to 6. Meanwhile the compressed oxygen tank had continuous flow at 1 L to 5 L per minute.
Researchers simulated three different metabolic rates to stimulate progressively higher exertion levels for each device with their specific settings. To mimic minimal exertion, the rate was 350 mL per minute; for moderate exercise, the rate was 850 mL per minute; and for heavy exercise, the rate was 1,200 mL per minute.
During these simulations, researchers evaluated end-tidal partial pressure of oxygen (PETO2) for each device to assess them against one another and clarify usefulness.
Through observation of each device, raising the metabolic rate generally meant decreasing PETO2, according to researchers.
Results from the simulation showed that when flow from the compressed oxygen gas tank went up, so did PETO2. Researchers found comparable increases in PETO2 to those observed in the compressed oxygen tank with the FDA cleared device using continuous flow at device settings of 1 L and 2 L per minute, but they noted “somewhat smaller elevations” when using the pulsatile-flow settings.
In terms of the OTC devices, researchers observed that only one (OTC3) may be suitable for patients since it demonstrated meaningful and steady rises in PETO2 as flow setting increased. Importantly, these elevations did not reach the same level as the FDA-cleared device at a given flow setting.
There was a modest increase in PETO2 with the OTC1 device, but this did not increase further when researchers raised the flow setting. Additionally, researchers found only very small rises in PETO2 with the OTC2 device.
“Physicians and respiratory care professionals should inform patients requiring portable oxygen that OTC devices may not meet their oxygenation requirements,” Casaburi told Healio.
This study by Casaburi and colleagues speaks to the growing issue of non-prescribed portable oxygen concentrators being sold online and encourages patients to be cautious when making a purchase, according to an accompanying editorial by Richard D. Branson, MSc, RRT, FAARC, professor in the department of surgery at the University of Cincinnati College of Medicine.
“How common are OTC portable oxygen concentrators? A quick search on Amazon.com yielded 823 results for the search term oxygen concentrator,” Branson wrote. “Many of the results included accessories including cannulas, backpacks, humidifiers, etc, but dozens of portable oxygen concentrators. The price of devices ranged from $200 [to] $700. Of note, a number of devices used model numbers identical to model numbers used by manufacturers of FDA-cleared devices. These are clearly deceptive advertising practices.
“For patients with lung disease requiring long-term oxygen therapy, caveat emptor — let the buyer beware,” he added. “Warning patients, however, is insufficient. We should attempt to prevent the sale of these devices to vulnerable patients.”
For more information:
Richard Casaburi, PhD, MD, can be reached at casaburi@ucla.edu.