Oxygen concentrators are the backbone of long-term oxygen therapy (LTOT) in the home. Oxygen concentrators started to enter the home care market with increasing numbers in the late 1970s. The concentrators made oxygen with purity of up to 93%, provided flow rates of up to five liters per minute, and allowed for oxygen cylinders or liquid oxygen (LOX). Cylinders and LOX are packaged gases and need to be refilled—which adds to distribution costs.

Early concentrators were considered stationary systems since they were designed to work off of AC power and their weight ranged from 50 pounds to 70 pounds. In the late 1970s and early 1980s, stationary oxygen was not considered a problem since patients were prescribed LTOT late in their disease and few patients were highly ambulatory. All that has changed. Now patients are diagnosed and prescribed LTOT early in their disease, and many (if not most) are capable and interested in ambulatory oxygen.

Inner workings
The technology has not changed much. Performance and reliability have improved, and features have added value. Basic operation consists of:

• A compressor that directs gas to the sieve beds;
• A molecular sieve that filters out nitrogen and leaves 93% +/- 2% oxygen that will be available;
• Valves that control the charge and purge cycle of the sieve beds;
• A holding tank that stores oxygen and smoothes out the flow to the patient; and
• A flow control device .
Oxygen purity sensors are available on many concentrators to indicate and/or alarm if oxygen purity drops below a therapeutic level. Some concentrators have diagnostics available to help providers quickly identify what may be malfunctioning.

Ambulatory Oxygen with a Concentrator?
Portable cylinders were first used as an emergency backup in case of a power outage or malfunction of the concentrator. Portable cylinders were also used as ambulatory oxygen for patients to take on short, infrequent trips away from the stationary system—such as a trip to the doctor. As patients were prescribed oxygen earlier in their disease, there was a need to provide more cylinders for routine trips.

The typical cylinder size for portable oxygen was E since it was used in other markets such as hospitals and ambulances. Early E-size systems consisted of a steel E cylinder, a brass regulator, and a steel tank cart. This system weighed more than 20 pounds, yet was not thought to be heavy until an LOX portable was introduced with half the weight and almost twice the operating time.

Oxygen-conserving devices became the option to compete with the weight and range capabilities of an LOX portable. Using a conserving device on a smaller cylinder provided a lightweight system that had an operating range similar to the LOX portables. An M9 cylinder with a conserving device was close to the performance of a nine-pound LOX portable. An M6 cylinder was close to the weight and range of a four-pound LOX system.

Patients became more ambulatory, requiring more cylinders and conserving devices to be placed in the home. Distribution costs again became an issue, and the concentrator/cylinder system for a highly ambulatory patients was as costly as an LOX system. There was a need to reduce distribution costs, yet still maintain oxygen therapy options for ambulatory patients.

Filling Portables in the Home
Two manufacturers have introduced concentrators that can fill cylinders from the oxygen that the concentrator produces. This eliminates the need for the provider to deliver cylinders on a monthly basis. Each device is different, with one manufacturer having the pressurizing unit separate from the concentrator, while the other has the pressurizing unit inside the concentrator.

The cylinders are proprietary to each manufacturer and are not interchangeable with the pin index system that most commercially available systems operate with. This is an FDA requirement, which is probably a good idea so elderly patients do not start their own oxygen filling services for their friends on oxygen.

Oxygen purity in the cylinders filled from a concentrator is 93 +/- 2%. This is not the 99% pure from standard cylinders, yet should not be an issue in most patients. The combination of 93% oxygen, the variety of oxygen- conserving devices used with each manufacturer’s products, and activity of an ambulatory patient may create a situation where clinicians will need to check patients’ oxygen levels and change the dose setting if it is not properly oxygenated.

Another manufacturer will soon reintroduce a system that uses a concentrator to generate oxygen that is liquefied and transfilled into an LOX portable. This concept has yields no distribution costs with the packaging of ambulatory oxygen in the home, plus the weight-to-range benefits of an LOX portable.

Portable Concentrators
Two manufacturers have developed small concentrators that weigh just less than 10 pounds. The benefits of a concentrator are the capability of generating its own oxygen from varying power sources, the light weight, and the potential to take the portable concentrator on an airplane, which just recently passed several regulatory hurdles. These small systems work off the same principle as the large concentrators, yet all components are smaller and a conserving device is necessary to dose the oxygen. If the patient’s needs do not exceed the capabilities of the portable concentrator, then the unit can serve as both the base and the portable, and will eliminate distribution costs for the provider.

New Cuts from CMS
There has been discussion that the new cuts for LTOT from CMS will range from 10% to 20%. Historically, the first response is to cut costs—of which distribution is the greatest cost in providing LTOT. LOX has one of the highest distribution costs, and in the past, every time there is a reimbursement cut, LOX is provided as a “have to” rather than a “need to” therapy. This time the patient may become more of a factor because of national advertising of portable LOX systems.

Currently, providers are using the most efficient system when providing LOX. A combination system that includes a concentrator for stationary oxygen and an LOX system for ambulatory oxygen is the best therapy for patients and has the lowest costs to maintain. The LOX base is only used to fill the portable, and the refill cycle for the base is close to 4 weeks.

The new systems will become more popular with the concentrators filling portables and the portable concentrators offering an alternative to traditional systems. These new systems will have higher initial costs for equipment acquisition, yet will not have the costs associated with distributing portable oxygen to the patient.

With the decreased costs for equipment delivery, the provider will need to shift to other services such as clinical programs to justify the monthly payment from CMS. If there is an attitude that there is not enough margin to add service, CMS may move to another distributor for a concentrator program that drops off equipment as their only service—using companies such as UPS or FedEx.

What Does Marty Think?
Marty is an active oxygen patient that likes to evaluate every option for LTOT. What about the new oxygen systems? The concentrators that fill cylinders are a nice idea since he does not like to have to wait or schedule the delivery of his LOX refills. Marty feels that he would need many more cylinders for this system to be a benefit to him. He currently uses an LOX base in his car to refill his portable and may use more than the two to three cylinders that are provided with the system. He also feels that the cylinders are larger than his current LOX portable.

He likes the portable concentrators, yet he could not sleep with them due to his need for CPAP and these systems using a conserving device—plus his exercise setting is 4 to 5 which might exceed the capabilities of portable concentrators. Marty is aware of the potential cuts in LTOT and is concerned that his current level of service may be affected by the cuts.

LTOT in the home has evolved to meet the needs of most patients. Reimbursement has always been associated with equipment rental and has never been based on effective outcomes. The next cuts will be based on balancing a budget and not on the needs of the patients. New technology may address the cuts, yet unless there is a basis for LTOT and a standard of care focused on health care needs, more cuts will occur.

Robert McCoy, RRT, is managing director of Valley Inspired Products Inc, Apple Valley, Minn. McCoy can be reached via email: bmccoy@inspiredrc.com.