Oxygen devices for lung disease show spotty performance
Posted Feb 27 2010 7:16am
Devices that help lung disease patients have oxygen therapy on-the-go may not always perform consistently — and may in some cases provide users with inadequate oxygen when they are active, a new study suggests.
The concern, say researchers, is that patients and doctors may interpret any resulting activity limitations as a sign that the lung disease is worsening, when it could instead the oxygen device.
The devices in question, known as oxygen conservers, are used mainly by people with chronic obstructive pulmonary disease (COPD), a group of lung diseases that includes emphysema and chronic bronchitis.
Oxygen conservers attach to the portable oxygen cylinders that many COPD patients carry because they need supplemental oxygen as they walk, climb stairs or perform other daily activities. The conservers are designed to dole out a set oxygen dose each time a person inhales; this allows the cylinders’ oxygen supply to last longer than it would if the oxygen flow were continuous.
In the new study, researchers at Case Western Reserve University in Cleveland, Ohio, tested four of what they describe as the most widely used oxygen conservers on the market. (They would not identify the specific brands.)
The researchers first bench tested each conserver to gauge performance, then had 13 COPD patients use each device in random order, at rest and during treadmill walking tests carried out over several weeks.
For comparison, the patients were also evaluated while breathing standard room air and while a wall unit supplied the room with 2 liters of oxygen per minute — the dose each patient required.
Overall, the study found, the conservers’ performance varied from product to product. And none of the devices consistently performed up to technical expectations, according to findings published in the American Journal of Respiratory and Critical Care Medicine.