STUART BASSINE, president of OxLife, remembers when concentrators weighed 247 pounds. That was 20 years ago, when the first concentrators began rolling off assembly lines. Nowadays, most hover in the 50- to 60-pound range, with a few even in the 30-plus-pound range. But patients are clamoring for even lighter devices they can take on the road more easily.

"I think there's a natural desire on the part of home oxygen patients to be able to ambulate," says Bob Mogue, director of sales and marketing for Chad Therapeutics. "Why wouldn't you want to move beyond 50 feet of connecting tubing?"

But smaller isn't always easier to devise-especially if a device has numerous parts. "The technology is much more difficult to make smaller," says Bassine. "When you make it small, you have to make it very precise to last."

Other manufacturers have different takes on this challenge of going smaller. "You're not going to get ambulatory with oxygen concentrators," says AirSep's Joe Priest. "But you may be able to get more portable."

"Even if you produced a portable concentrator," says Gregg Gaskins of Nidek Medical Products, "it's not going to be light enough to replace a liquid cylinder orportable oxygen. It will never get to the point of being light enough to be a truly portable oxygen concentrator." In other words, he says, you might find folks hauling concentrators on road trips, but you won't find them trekking the trails with the devices on their backs.

Ed Radtke of SeQual Technologies disagrees. Patients want a portable product "and they're going to get it from us," he says. "Our products are easily scaled. We have an oxygen concentrator [in the lab] that is the size of a beer can."

Indeed, the commercialization of a concentrator in the 20- to 25-pound range may not be too far down the road. It's already out in Europe and on its way to the United States: Italian manufacturer Sim Italia produces the 22-pound TravelSome concentrator, which has a reduced flow capability-either 1.2 lpm on continuous flow or 2.5 lpm on pulse-demand flow. According to Susan Muratori, product manager for oxygen concentrators for export sales, the company believes the demand is big enough to warrant forming its own provider company to market the device in the United States. -S.H.