Comfort levels for home testing vary among experts, who argue that, on one hand, home test outcomes vary radically from those of the sleep laboratory or, on the other, that they provide much needed services for people who otherwise would go untreated.

So numerous is the American population of individuals at risk for sleep apnea that there is not enough laboratory capacity in the United States to screen them all, some experts postulate. As such, the dominant setting for those screenings eventually will be the home. Respiratory therapists can expect to play a role, even though it is unlikely that Medicare and Medicaid will ever reimburse for home sleep testing.

Utilizing the home as the main venue for sleep apnea screening is a source of controversy among sleep professionals. At issue is whether it is better to test individuals under the less-than-ideal conditions of a home setting and be assured of getting more people screened or to insist that everyone be tested only in a laboratory environment, which would mean far fewer people are looked at.

“An advantage of home studies is that you can make testing available to a great many more people, especially those who live in rural areas far, far away from the nearest sleep center,” says Philip R. Westbrook, MD, who founded and directed sleep centers at Mayo Clinics in Rochester, Minn, and Cedars Sinai Medical Center in Los Angeles. “If we try to wait for the availability of scheduled space in a lab, too many at-risk individuals will go undiagnosed. Their numbers are growing faster than we can harvest them. That’s why home sleep testing is so important right now.”

Mildly disagreeing is Pamela Minkley, RRT, CPFT, RPSGT, supervisor of the Ingham Regional Center for Sleep & Alertness in Lansing, Mich., and a past president of the Association of Polysomnographic Technologists. “There’s a huge difference among the types of studies performed in the home,” she says. “In-home studies range from simple screenings to complex polysomnography and may not yield an adequate diagnosis. We know that disorders often occur together. If a patient is properly studied, similar to a laboratory setting polysomnography, there’s a much greater likelihood that coexisting morbidities would be caught before the patient suffers a potentially life-threatening or life-altering event at significant cost to the health care system. So, let’s say a ‘home study’ is actually a screening and comes back with a negative result. Will we ever get that patient back in the medical system where he can receive the help he needs, or will he—thinking himself fine—just go on about his way, not realizing the health danger he’s in?”

Ideal Equipment
“Many people feel the accuracy, reliability, sensitivity, and specificity of simple devices have not been adequately proven,” says Westbrook. “I disagree with them. I think the evidence is pretty much there that these devices can be accurate. Before I retired 2 years ago from clinical practice, I conducted a lot of studies using portable home recording devices for the diagnosis of sleep apnea. I felt this was quite successful. My experience is that, in home sleep testing, you must use the device or devices with known sensitivity and specificity for the question being asked—in this case, sleep apnea.”

Westbrook adds that, in his home sleep studies, he routinely measured oxygen saturation, air flow, effort, and pulse rate. “The standard for calling an event an apnea or a hypopnea requires a 4% desaturation,” he says. “That’s a huge desaturation for someone with relatively normal lungs at sea level. As a result, a lot of obstructive events are missed using that 4% standard. They are incorrectly labeled as no-flow limitation events or respiratory effort-related arousals. At minimum, you should have a very accurate and fast-responding pulse oximeter. It has to be capable of showing relative changes of 1% to 2% and of closely tracking desaturations and the rate of rise in resaturations.”

The trouble is that most oximeters are designed for critical care work, not for sleep studies and the measurement of repetitive desaturations and resaturations. With that in mind, Westbrook lately has worked to develop inexpensive home monitoring technology specifically for sleep apnea screening. He is now medical director of a company that may within the next year or two introduce a system that includes a simple-to-use oximeter that can measure down to at least a 2% desaturation.

Triage, Follow-up
Utilizing the best equipment is not that necessary for success in home sleep testing. Also required—and perhaps of paramount importance—is good medical triage of the patients before they are studied, says Minkley.

“Every tool we have available to study sleep at home right now probably has some valid use,” she says. “The question is: for whom is home testing appropriate, and under what circumstances? My position is that it’s best determined by a sleep physician who is looking at the whole picture for the patient. That picture would include any previous data; whether the patient is in treatment; whether this is a screening test, follow-up, or diagnostic; and how accessible the patient is. The sleep physician also must consider the environment in which it would be best to do the study.”

Another consideration is the desirability of having clinician intervention. “It’s assumed that, if you’re going to do a home study, it’s going to be unattended—even if it’s monitored from some distance away,” says Minkley. “That’s because it’s too expensive to put a sleep technologist physically in the home to attend the study. Plus, many technologists are uncomfortable going into a home and staying there all night, in an environment they know nothing about. ”

Along with triage, there must be follow-up after the study is completed. Good follow-up should entail several actions. “First, the patient needs to receive the results of his study,” Minkley says. “Then, those results need to be discussed with a physician who is trained in sleep. Without this discussion, the patient isn’t likely to find out the cause of his initial complaint. Second, if the study comes back positive for any of a number of sleep disorders, then the patient needs follow-up so that appropriate treatment can be initiated.”

Naturally, triage and follow-up are two facets of home sleep testing in which respiratory care practitioners can prove themselves vital players. “There’s certainly a role for respiratory therapists in the identification and testing of candidates for home sleep testing,” says Westbrook. “There also will be instances where a respiratory therapist’s expertise is required for setup of some of the more complicated pieces of equipment that can be used at home. Then, there’s patient education, another area where respiratory therapists can make a difference, especially if the screening leads to treatment.”

Minkley indicates that use of respiratory therapists and registered sleep technologists in the triage and follow-up phases of testing would go a long way toward solving the problem of patients slipping through the cracks when studies are ordered by individual physicians and others not part of an organized continuum of care.

Making the $$$ Case
The cost of an unattended, four-channel sleep test at home runs about half that of a full, attended polysomnographic study conducted in a sleep center. In the Southern California market, for example, the latter fetches up to $600, while the former carries a price of no less than $300.

But while the attended, in-laboratory study can be reimbursed by Medicare, the same is not true of the unattended version at home. One solution, Westbrook argues, is to get the cost of home studies down low enough that patients will not mind paying for them out of pocket. He contends that this threshold amount is $100. Failing that, the alternative is to demonstrate home sleep testing as so invaluable that HMOs and other private payors will not be able to say no to it whenever it is prescribed as an apnea screening tool.

“If you have the physicians and technologists with the skills to provide the service, including determining which patients it’s appropriate for, then there may be a possibility that you can talk directly to third-party payors about getting paid for these studies,” says Minkley. “You have to demonstrate medical appropriateness and cost-effectiveness, supported by data and literature.

“Don’t assume that a study done in the home is always more cost-effective. For example, if you did a screening in the home but didn’t obtain enough information to let you compute RDIs or apnea-hypopnea indices and verify that the patient slept as well and in all positions, then that information couldn’t be used to justify a CPAP trial. For that, you’d have to repeat the study, only this time in a sleep center, in effect making the home testing not very cost-effective.”

Rich Smith is a contributing writer for RT.