Should Sleep Labs Embrace Unattended Studies? – David Barone

Most sleep labs utilize polysomnography (PSG) as their sole methodology to diagnose nocturnal breathing disorders. Ambulatory tests (a.k.a. “home studies” or “unattended sleep studies”) are offered by various service providers and health networks as an alternative to rule-out sleep apnea or to confirm the presence and severity of the disease in patients presenting with indicative symptoms. Though hundreds of thousands of patients have been successfully diagnosed using unattended testing, many sleep labs shy away from such studies either out of fear that they may negatively affect the labs’ operations, or concerns that such studies may not provide adequate clinical outcomes.

Successful campaigns by the medical community and organizations like the American Academy of Sleep Medicine, the National Institute of Health and the National Sleep Foundation have contributed to increased awareness among the general public and healthcare practitioners, and to a growing demand for sleep services. With growing understanding of the significant prevalence of sleep apnea and its implications for other morbidities and patients’ quality of life, more physicians now actively screen their patients suspected of sleep apnea and refer them to sleep labs to establish definitive diagnosis and initiate treatments. The growing interest in sleep disorders, coupled with the introduction in recent years of new technologies designed specifically to diagnose sleep apnea in an unattended setting have stimulated an active debate about the role of alternative clinical pathways to the management of these patients. The issue received further urgency following a 2006 report by the Institute of Medicine which sta ted that ”polysomnography, the ‘gold standard’ procedure for the diagnosis of most sleep disorders, is not readily available for everyone who needs it.” The authors of the report stated that “access to portable diagnostic screening procedures and streamlining initiation of treatment would clearly be advantageous” and recommended that “the rationale application of technology needs to be coupled with a reexamination of the role of diagnostic testing in case identification and disease management, clarifying optimal use of objective physiological monitoring data, including data obtained from portable monitors, in clinical diagnosis and management algorithms.”1

A review sponsored by the American Thoracic Society, the American College of Chest Physicians and the American Academy of Sleep Medicine published in 2004 concluded that “given the available data, the use of portable devices was not recommended for general screening.”2 Other reports, some published more recently, reached different conclusions, suggesting that ambulatory studies, when properly utilized and operated by skilled professionals, may indeed add to the arsenal of diagnostic options available to practitioners. The Minneapolis-based Institute for Clinical Systems Improvement (ICSI) has recognized the importance of this issue, and in its 2006 guidelines3 stated that “in patients with a high pretest probability of obstructive sleep apnea (OSA), unattended portable recording for the assessment of obstructive sleep apnea is an acceptable alternative to standard polysomnogram in the following situations: (i) patients with severe clinical symptoms that are indicative of a diagnosis of obstructive sleep apnea and when initiation of treatment is urgent and standard polysomnography is not readily available; (ii) for patients unable to be studied in the sleep laboratory, and (iii) for follow-up studies when diagnosis has been established by standard polysomnography and therapy has been initiated.” The guidelines also state that “employment of portable monitoring as a second-best option is not likely to result in harm to patients with a high pretest probability of OSA, and may result in less risk than leaving the condition undiagnosed.”

While this debate will undoubtedly be further pursued by clinicians, researchers and health policy makers, it is apparent that clinical needs, shifts in healthcare environment and continuing technological developments will most likely lead to growing acceptance of simpler diagnostic options, requiring all sleep labs to assess their current service models and determine how to respond to the shifting landscape.

Studies published in recent years confirmed the performance and efficacy of home studies in the clinical diagnosis and management of sleep apnea. These studies documented acceptable sensitivity and specificity of tests, a high degree of patient acceptance and low failure rates, as well as comparable outcomes to PSG, achieved at considerably lower costs. 4,5,6 The NIH-sponsored Sleep Health Study7 and other studies demonstrated that even EEG measurements are feasible in the home environment. Yet, the inherent complexity associated with such recordings limited its use in the home setting, raising concerns by sleep specialists as to whether that lack of information about the patient’s sleep architecture and actual sleep time affect the analysis of disease severity. New devices using advanced technologies can now provide significant information about sleep, including determination of actual REM sleep, sleep time and sleep fragmentation, without measuring EEG. One of the more noticeable examples is the Watch -PAT, developed by Itamar Medical Ltd., which incorporates a sensor able to monitor minute changes in peripheral arterial vasomotion caused by apnea events. Coupled with a built-in actigraphy, the Watch-PAT provides a reliable and accurate determination of sleep, wake and REM states, and together with measures of heart rate and saturated blood oxygen, generates an accurate assessment of indices based on actual sleep time.8 Multiple studies validated the reliability of the device, its ability to recognize sleep and wake states, and its accurate measurement of apneic events when used either in the lab or at the patient’s home.9 The Watch-PAT points to the direction taken by other participants in the medical technology industry, responding to providers’ needs by developing a new generation of simple-to-use and patient-friendly devices. Such devices leverage advanced sensing, electronic and software technologies to provide a greater amount of clinically relevant and reliable information, the flexibility to ope rate cost-effectively in multiple points-of-service and lowering costs.

In-spite of the availability of new technologies offering alternatives to PSG and many publications evidencing their performance, the majority of patients suffering from sleep disorders are still sent to sleep labs, as referring physicians and patients recognize the medical expertise and broader resources available through these venues. Yet, a growing number of sleep labs are shifting their views from seeing home tests as a threat to patient care and at times, even to their own operations, to realizing that such technologies actually represent an opportunity to enhance and expand their services by rationally integrating PSG and portable tests. Some examples of how portable technologies are benefiting providers of sleep services and patients alike include:

Reducing waiting time. Many labs struggle with the growing demand for services that extends waiting time for patients suspected of sleep apnea to weeks and even months, frustrating patients and referring physicians alike. Any sleep lab faced with increasingly longer wait times can in a relatively short period of time, reduce it by qualifying patients who can be tested at home, applying its own clinical criteria for which patients are most suitable for such tests.

Addressing special needs. It is well-established that many patients referred to sleep labs fail to schedule a study, either because they are intimidated by the experience or simply consider spending an entire night in an outside testing facility too inconvenient. Other patients may have special medical or physical needs that limit their ability to undergo a study in a sleep lab, or given the choice, they simply prefer a test done in the privacy of their homes. Without an alternative to the in-lab PSG, many of these patients remain untreated. The home study route enables providers to offer to many of these patients a clinically acceptable solution, which, when appropriate, can be followed by an in-home APAP study, rather than leaving these patients untreated.

Responding to an immediate need. Most sleep labs schedule their patients weeks in advance and thus, when a situation requiring quick turnaround time arises (e.g. out-of-town patients, high risk cases, etc.), the unexpected need can be addressed with an at-home study rather than a shuffling of the schedule.

Supporting inpatient studies. Hospital-based sleep labs are requested from time-to-time to assess an inpatient located in an ICU, a CCU or another ward. The growing awareness of the prevalence of sleep apnea among CHF, diabetics and geriatric patients, which are prone to frequent hospitalizations, is leading to a surge in the need for in-hospital services. The ability to set up a sleep study for patients within minutes and without interfering with other support systems favors the use of the smaller portable devices. Furthermore, the auto-analysis software available with some of the newer portable systems provides diagnostic results within minutes after the data is complete, enabling the hospital’s staff to expeditiously incorporate the results into the ongoing care decisions.

Conducting follow-up studies. Many patients undergoing either positive pressure or oral appliance therapies require periodic testing to confirm the need for continuing intervention, or to determine an adjustment in treatment parameters. Presently, due to the over-extension of sleep labs and the reluctance of many patients to come to the lab for additional studies, many of them are under-managed following initial intervention. Employing a home study for an annual evaluation, or otherwise, when medically indicated, may optimally address such needs.

Evaluating pre-operative patients. Recognizing sleep apnea prior to surgical procedures may reduce the risk of post-operative complications for patients with this disease. Recently published guidelines by the American Society of Anesthesiologists,10 as well as proposed guidelines by JHACO11 to institute pre-op sleep apnea screening are expected to fuel a significant increase in the case loads involving such patients, which in many instances cannot be accommodated by existing sleep lab facilities. Rather than ignoring these clinical cases or losing such patients to other services, labs may offer the required quick turnaround service by offering a simplified home study, which will be adequate for most of these cases.

Pediatric testing. There is a growing body of literature pointing to the prevalence of sleep apnea among children, often diagnosed and treated inappropriately. Undiagnosed sleep apnea has been associated with behavior, cognitive and learning deficiencies among this population. Since most of these patients require an assessment of breathing disorders, home studies are most conducive clinically and operationally considering the inconvenience and often, parental participation, when conducting the test in a hospital-based facility.

Expanding outreach programs to referring physicians. Cardiologists, family practice physicians, otolaryngologists, bariatric surgeons and other specialists are gaining appreciation of the importance of testing patients for sleep breathing disorders. Sleep labs offering also home studies are able to respond to physicians requesting a simpler test for some of their patients, while still contributing their medical expertise and when appropriate, conducting subsequent diagnostic and treatment services.

An alternative to fixed-bed satellites. A growing number of labs are setting satellite operations, consisting of smaller labs, distant to the main facility. While these facilities enable the organization to capture additional referrals, they do carry a financial cost associated with setup and operation and at times, stretch an already thin staff. This challenge is especially acute in rural areas, as low population density cannot justify a sleep lab staffed by qualified technicians in each locale. Conducting a home test, at least for the initial diagnosis of such patients, is often the most clinically and financially prudent approach.

Employee screening. Some labs have already instituted or are considering expansion of their programs to the employer market, offering screening and diagnostic services to commercial drivers, shift workers, first responders and other employees engaged in critical tasks. Portable and user-friendly systems are an ideal technology and in most instances, the only practical solution for this emerging market.

After shunning home studies for a long time and viewing them as a competitive threat, a growing number of sleep labs are integrating home studies for some of the applications outlined above or other which suit their evolving needs. Adding portable studies to a sleep lab can be accomplished in most instances relatively quickly and with a minimal investment. Other than the acquisition cost of the devices themselves, there are little other up-front costs. Operational hurdles are minimal, since training sleep technologists on such devices is accomplished in a relatively short time, as this highly trained staff is already familiar with patient education, test preparation and data analysis, and with automatic or otherwise simplified scoring, existing staff is in most instances able to absorb the incremental home studies without additional headcount.

As more experience is gained, sleep labs will find out that home studies are not a threat to quality patient care, but rather an important modality that when properly utilized, augments the lab’s current services. Well-managed programs offering both PSG and home testing can gain tangible operational and marketing advantages, strengthen sleep labs’ competitive positions within their respective markets, improve their financial results and most important, enhance and expand quality patient care.

David Barone, MSc, MBA,
Principal, Boston MedTech Advisors, Boston, MA.


1. Institute of Medicine. Sleep Disorders and Sleep Deprivation, An Unmet Public Health Problem. April 2006.
2. Chesson et al. Practice Parameters for the Use of Portable Monitoring Devices in the Investigation of Suspected Obstructive Sleep Apnea in Adults. Sleep 2003; 26:907–913.
3. Pittman et al. Using a Wrist-Worm Device Based on Peripheral Arterial Tonometry to Diagnose Obstructive Sleep Apnea: In-Laboratory and Ambulatory Validation. Sleep 2004; 27:923–933.
4. Westbrook et al. Description and Validation of the Apnea Risk Evaluation System: A Novel Method to Diagnose Sleep Apnea-Hypopnea in the Home. Chest 2005; 128:2166–2175.
5. Townsend et al. Assessing Efficacy, Outcomes, and Cost Savings for Patients with Obstructive Sleep Apnea Using Two Diagnostic and Treatment Strategies. Sleep Diagnostic and Therapy, 2007: 1.
6. Iber et al. Polysomnography Performed in the Unattended Home Versus the Attended Laboratory Setting-Sleep Heart Health Study Methodology. Sleep 2004; 27:536–540.
7. Bar et al. Evaluation of a portable device based on arterial peripheral tonometry (PAT) for unattended home sleep studies. Chest, 2003; 123:695–703.
8. Herscovici et al. Detecting REM Sleep from the Finer: Automatic REM Sleep Algorithm based on Peripheral Arterial Tone (PAT) and Actigraphy. Physiol. Meas. 2006; 27:1–12
9. Pittman et al. Follow-Up Assessment of CPAP Efficacy in Patients with Obstructive Sleep Apnea using an Ambulatory Device Based on Peripheral Arterial Tonometry. Sleep and Breathing, 2006; 10:123–131.
10. Practice Guidelines for the Perioperative Management of Patients with Obstructive Sleep Apnea: A Report by the American Society of Anesthesiologists Task Force on Perioperative Management of Patients with Obstructive Sleep Apnea. Anesthesiology 2006; 104:1081–1093.
11. The Joint Commission on Accreditation of Healthcare Organizations. Potential 2008 National Patient Safety Goals and Requirements. December 4, 2006.

Leave a Reply

Your email address will not be published. Required fields are marked *