Long-term oxygen therapy (LTOT) patients want the same things all of us want: The ability and freedom to go where we want to go for as long as we would like to be gone without worrying about running out of oxygen. Finding ways to do this is the challenge.

Most patients on LTOT use either liquid oxygen (LOX) or oxygen cylinders as their portable systems. It is a good solution since the use of oxygen conserving devices (OCDs) have allowed these systems to become smaller with a greater ambulatory range. However, it is not an ideal solution as these systems still need regular refills to work. That means patients must have access to stationary oxygen delivery systems while their portables are refilled from liquid oxygen units, or they must carry with them additional oxygen cylinders for the portable system.

In addition, for many HME providers, the most expensive portion of LTOT is the ambulatory oxygen system because of the need to routinely refill portables. Reducing the need for costly deliveries of oxygen refills is important given that the oxygen reimbursement from the Centers for Medicare & Medicaid Services has dropped over the past two decades.

Concentrator Advantages
Oxygen concentrators are a popular stationary system choice since the units operate from electricity and do not require refilling. Available since the early 1980s, concentrators have evolved to the point where most respiratory therapists now consider them efficient and reliable for stationary home oxygen therapy. Current concentrators are quiet, require minimal service, and have a price that is considerably lower than what the first concentrators cost in the early 1980s.

However, most concentrators still weigh around 50 pounds and typically have no battery backup. Therefore, they cannot easily travel with a LTOT patient on the go.

A portable oxygen concentrator weighing less than 10 pounds with enough battery power for it to last up to 4 hours at 2 liters per minute (lpm) continuous flow could help reduce the costs associated with providing ambulatory oxygen to LTOT patients by eliminating the need to deliver refill canisters. For the patient, it may offer greater freedom by making oxygen available anywhere there is electricity.

Current Situation
Even though providers and clinicians have long desired a portable oxygen concentrator, it is only recently that advances in oxygen concentration technology, oxygen conservation, and batteries have made such a device possible. This first product weighs less than 10 pounds, but its operating time is under the 4 hours at 2 lpm desired.

Still, it has gained the attention of both patients and clinicians and has stirred the interest of other manufacturers.

How the home health care industry will incorporate portable concentrators remains to be seen. There are several factors to consider.

Weight: How heavy devices are has become a key factor to patients’ use and compliance with their oxygen prescriptions. Early portable oxygen systems were compressed gas cylinders that could weigh up to 20 pounds (steel E size cylinder with brass regulator and steel cart) and last up to 5 hours at 2 lpm continuous flow. LOX became the portable of choice for ambulatory patients since an 8.5-pound portable could provide the patient with up to 8 hours of operating time at 2 lpm.

OCDs provided gas delivery efficiency and could offer the patient 5 hours of operating time with a small (M6) aluminum, 5.5-pound cylinder with the OCD rate set at 2 and 20 breaths per minute. Furthermore, new LOX systems have lowered that weight to 4 pounds with an operating time of 6 to 8 hours at a setting of 2 and 20 breaths per minute by incorporating conserving technology.

A 10-pound portable concentrator is not as light but it still can move easily on a cart or into a car.

Range: Patients want a portable system that will give them the freedom to be away from their stationary system as long as possible without compromising safety. Most patients seem to want to be ambulatory up to 4 hours and a few patients still work and need to be away from their stationary system for 8 to 10 hours.

The safety factor requires patients to estimate the operating time of their portables and plan to have 1 hour of operation left in the systems when they reconnect with the base units. But estimating the operating time can be difficult since respiratory rate when using a conserving device, accuracy of contents indicators, and gas leaks from connections or venting loss from a LOX system affect this calculation.

In contrast, portable concentrators will not run out of oxygen since they manufacture their own. On an extended outing, AC power or the automobile adapter can provide energy for most of the time. The variable will be battery life as a bridge from one power source to another. Battery range will affect weight, therefore, a balance will come between weight and operating time.

Therapy: A portable concentrator would be ideal if it could be used 24 hours a day. To accomplish that objective, the device would need to be used at rest, during exercise, and while the patient was sleeping. Rest would be the easiest to accomplish since the patient could plug the device into an outlet to eliminate the power issue and they would have a lower oxygen demand.

Ambulatory application of a portable concentrator will bring several factors into consideration. With activity, respiratory rate increases to provide more oxygen to the muscles being used. The rate at which a concentrator can generate oxygen is limited. At some combinations of setting and breathing rate, the device may not be able to keep up, and the purity of the gas will decrease.

Currently, the oxygen content of most concentrator gas is less than that of cylinder or LOX systems. A typical concentrator may require 1.14 times as much gas at 90% concentration to have the same therapeutic benefit as 100% gas.

OCD systems also may vary in their oxygen delivery at similar settings. This can create confusion when comparing systems. To evaluate the capability of a portable concentrator, you need to look not only at the number on the dial, but how much gas is delivered at that setting, what the gas purity is, and how fast the patient can breathe before the unit cannot keep up. Clinicians will need to evaluate the patient during activity to ensure that the proper setting is selected.

Using a portable concentrator while asleep will require reliable triggering of the OCD. At this time, most OCD manufacturers do not recommend sleeping with an OCD and those that do, recommend the patient be tested with overnight oximetry to ensure proper oxygenation.

Sleeping with a portable concentrator is an important issue for patients who would like to take the device on vacations. The convenience of the lightweight concentrator may be limited if a continuous flow concentrator must be brought along for sleeping.

Other factors: To determine value and applications, also consider other factors related to portable concentrators. Patients will test the devices’ durability, since as these devices are moved, they will be dropped, bumped, and jostled. Stationary concentrators do not experience this type of activity, so there is no history of what happens to concentrators when they are subjected to a great deal of movement.

Cost and reimbursement also are critical factors for most home health care products. If the cost of a portable concentrator is too high, or there is little or no reimbursement, whoever purchases the product will need to determine the cost/benefit value.

An Ideal Solution?
A portable concentrator can offer a new level of freedom to patients by eliminating dependence on a stationary oxygen source. Portable concentrator users can have oxygen anywhere there is electricity—with battery power to get from one location to the next. However, portable concentrators have yet to develop the low weight and long independent run time of a LOX or cylinder system. This balance will likely shift as the technology continues to evolve.

The simplicity of a device that can be used as both a stationary and portable device could eliminate many of the costs associated with providing LTOT in the home and encourage patients to maintain a normal lifestyle. The first portable oxygen concentrator on the market has stirred interest and development of more products that will address the growing LTOT market and the patients’ needs for mobility and convenience—a good situation for both patients and providers.

Bob McCoy, RRT, is managing director of Valley Inspired Products, Savage, Minn. Contact him at bmccoy@inspiredrc.com.