In-home polysomnography performed by skilled technicians can benefit sleep centers, payors, and sleep center referral sources

The technique of performing portable polysomnography recordings in the home setting has been in existence for quite a few years. Many discussions and debates have occurred throughout the years relating to the level of quality, cost, and appropriateness of this methodology. When considering these issues, it is first important to be aware of the potential for terminology confusion. Portable polysomnography is very different from portable sleep testing. The type of data acquired, information retrieved, impressions derived from the data, and costs associated with each type of procedure are entirely different and unique.

Portable Sleep Testing vs Portable Polysomnography
Portable sleep testing is a method that should ideally be used as a screening tool to identify the presence of obstructive sleep apnea (OSA). The parameters included in this method of testing typically consist of oximetry, nasal/oral airflow, and respiratory effort. Due to the relatively low cost of the equipment used in this method, it is often found to be an attractive alternative to the more expensive conventional in-laboratory testing method; however, the principal obstacle encountered when using this method as an extension of, or alternative to, the conventional sleep laboratory is the incidence of negative findings. Due to the absence of the electroencephalographic (EEG) parameter, it is impossible to document objective evidence confirming whether the patient was asleep during the recording; therefore, false-negative findings can be common. Additionally, due to the lack of body position monitoring, which is absent in many brands of equipment designed for this testing method, a positional component of sleep-disordered breathing is impossible to rule out as well.

The most effective use for portable sleep testing is to confirm the presence of sleep apnea in the home, and to allow the test to replace the “night one” component of the conventional 2-night in-laboratory study protocol. The patient can then be studied in a conventional sleep laboratory for nasal continuous positive airway pressure (NCPAP) titration. This approach will allow the testing service provider to reach more patients and reduce scheduling backlog; by comparing aspects of the portable recording data with the in-laboratory recording data, quality equipment utilization as well as patient outcomes can be measured and analyzed.

Most recently, portable sleep testing has also been used as a method to identify patients with severe OSA in the absence of formal polysomnography. If the test yields positive findings within a severe category, the patient is placed on an auto-titrating NCPAP machine and followed clinically. If the test yields negative or positive findings within the mild to moderate category, the patient is then referred for formal evaluation within the sleep center. This algorithm is becoming more and more popular within the primary care community as a means to bypass sleep center scheduling backlogs, as well as to reduce costs.

Portable polysomnography, as compared to portable sleep testing, will yield much more information. Most significantly, the presence of EEG will allow for an objective differentiation of wake vs sleep, and will allow for formal sleep staging. Unfortunately, the additional physiological parameters allow for more types and degrees of technical artifact to present. As a result of the study being performed in an “unattended” fashion, there is the potential for artifact to persist throughout the recording, make the results uninterpretable, and increase overall costs due to restudies.

Attended vs Unattended Studies
The most common and frustrating aspect of unattended portable polysomnography recording is the existence of artifact. Electrodes and sensors falling off during the recording, and improper patient operation of the equipment, are the most common sources of artifact in the home setting. Protocols have been developed and tested, which include a technician in attendance during the recording. Unfortunately, this clearly defeats the intent of reducing costs, may make the patient uncomfortable with a “stranger” present in their home while they are sleeping, and raises the potential for liability issues related to accusations of improper professional conduct. Attempts have been made to allow for remote modem communications by a technologist, which allows for remote control of amplifier filter adjustments and viewing of the data acquisition, but does not address the issue of replacement of faulty electrodes or sensors. Additionally, outdated telephone systems in rural areas result in very difficult, if not impossible modem communications.

Advantages of In-Home Portable Polysomnography
• Sleep disruption, sleep onset insomnia, and changes in typical sleep patterns can occasionally occur in patients when sleeping in an unfamiliar environment such as a sleep laboratory. This occurrence is commonly referred to as “first-night effect.” Performing in-home polysomnography can often minimize first-night effect.

• If performed in an unattended fashion, in-home portable polysomnography can reduce operating costs to the testing service provider, and subsequently reduce costs to the patient.

• It allows the testing service provider to reach more patients. When the results of in-home polysomnography are accepted as confirmation of the presence of sleep-disordered breathing and allowed to take the place of the night-one component of the conventional 2-night testing protocol, patients can then spend only 1 night in the sleep laboratory for NCPAP titration, therefore expanding the laboratory testing capacity.

• Portable monitoring allows the testing service provider to reach people in remote, rural areas who most likely would not travel to a conventional sleep center.

Disadvantages of In-Home Portable Polysomnography
• As the cost of delivering health care continues to increase, reimbursement for health care continues to decrease. Reimbursement for unattended portable polysomnography monitoring has steadily declined during the last few years to a current level that makes it extremely difficult to profit, let alone break even; however, contracting with local health insurance companies or other health care payors may allow the testing provider to perform the service at a negotiated fee, thereby reducing unfavorable financial results.

• Unattended portable polysomnography monitoring will undoubtedly include multiple varieties of technical artifact, which may result in an uninterpretable recording.

• Effective NCPAP titration cannot be conclusively or objectively documented during an unattended study.

Key Issues to Consider for In-home Polysomnography
• Can other physiological conditions that may coexist with sleep-disordered breathing or mask as sleep-disordered breathing be detected (early rapid eye movement [REM] latencies, periodic limb movements in sleep [PLMS], nonapneic breathing related arousals, seizure activity)?

• If your protocol requires the patient to start, end, or pause the recording, how many patient-controlled equipment operation errors occur? If they occur frequently, perhaps simpler equipment should be used.

• If NCPAP is titrated in the home, is the sleep technician able to document effective pressures during REM sleep in the supine position?

Keys to Maintaining Quality
• Always include EEG as a parameter. It is critically important to be able to document whether sleep has in fact occurred.

• Never rely exclusively on computer-automated sleep and respiratory analysis programs that commonly accompany portable polysomnography equipment.

• Always be financially prepared to repeat technically unacceptable studies at no charge to the patient.

• Although auto-titrating NCPAP devices have been shown to be effective in numerous studies, it is currently impossible to accurately predict which patients will be effectively treated.

• Use portable polysomnography only to rule out OSA or PLMS. In-depth, prescreening of patients via a sleep history questionnaire as well as physician consultation is recommended to determine the patients most likely to have OSA or PLMS.

In summary, when used by skilled technologists who are aware of the above-mentioned quality issues, in-home unattended polysomnography can be a beneficial tool. For sleep centers, it can expand patient throughput by eliminating the conventional night-one baseline component of the conventional 2-night protocol. For sleep center referral sources, it can reduce the waiting period due to scheduling backlogs, particularly for the severe OSA patients. For payors, it can potentially reduce costs and for the patient, it can add convenience as well as reduced waiting time.

Todd Eiken, RPSGT, is the director of the Metropolitan Sleep Disorders Center, St Paul, Minn, and past president of the Association of Polysomnographic Technologists.