CleveMed Blogs

In this week’s post we decided to write about one of the more popular topics suggested by our readers: definitions of types of sleep studies devices according to CMS (the Center for Medicare & Medicaid Services) and AASM (the American Academy of Sleep Medicine). Hope these quick summaries help in understanding these terms better. CleveMed currently has three devices that fall within these defined categories for the purposes of sleep (Type I - Sapphire PSG, Type II - Crystal Monitor PSG, and Type III - SleepScout).

Definitions according to Center for Medicare & Medicaid Services (CMS) Guidelines

Type I – Attended studies (Sleep studies that are preformed with the oversight of a sleep technologist.) with full sleep staging (Sleep staging monitors the transition through the sleep stages. Traditionally with the use of EEG electrodes that monitor the brain). Type I devices must includes the following channels:

• EEG
• EOG
• ECG/Heart rate
• Chin EMG
• Limb EMG
• Respiratory effort at thorax and abdomen
• Air Flow from nasal canula thermistor and/or X-Flow (AASM re- commends RIP technology
• Pulse Oximetry
• Additional channels for CPAP/BiPap levels, CO2, pH, pressure, etc.

(CPT #95810 Baseline PSG, 95805 MSLT, 95811 Titration)

Type II – Home sleep study test (HST) with type II portable monitor, unattended(Sleep studies that are preformed without the oversight of a Sleep Technologist.); minimum of 7 channels. Type II devices must includes the following channels:

• EEG
• EOG
• ECG/heart rate
• EMG
• Airflow
• Respiratory effort
• Oxygen saturation

(HCPCS #G0398)

Type III – Home sleep test (HST) with type III portable monitor, unattended; minimum of 4 channels. Type III devices must includes the following channels:

• 2 respiratory movement/airflow
• 1 ECG/heart rate
• 1 oxygen saturation

(HCPCS #G0399, CPT 95806)

Type IV – Home sleep test (HST) with type IV portable monitor, unattended; minimum of 3 channels. Type IV devices must allow channels that allow direct calculation of an AHI or RDI as the result of measuring airflow or thoracoabdominal movement. Alternatively devices that record other information to derive AHI or RDI must be approved by CMS through the review of published peer-reviewed medical literature.
(HCPCS #G0400)

Definitions according to American Academy of Sleep Medicine (AASM) Guidelines

Type I - Monitoring devices perform in-laboratory, technician-attended, overnight polysomnography (PSG) and are discussed separately. (CPT #95810 Baseline PSG Study, CPT #95805 MSLT Study and CPT #95811 Titration Study (CPAP))

Type II – Monitoring devices can perform full PSG outside of the laboratory. The major difference from type 1 devices is that a technologist is not present. These devices are called comprehensive portable devices. (CPT #95807)

Type III – Monitoring devices do not record the signals needed to determine sleep stages or sleep disruption. Typically channels include:

• Four physiologic variables are measured including:
• Two respiratory variables (eg, respiratory movement and airflow)
• Cardiac variable (eg, heart rate or an electrocardiogram)
• Arterial oxygen saturation
• Some devices may have other signals including a monitor to record snoring, detect light, or a means to determine the body position.

(CPT #95806)

Type IV – These devices are called continuous single or dual bioparameter devices. Monitoring devices record one or two variables and can be used without a technician. Typically channels include:

• Arterial oxygen saturation
• Airflow

In-lab sleep testing requires extensive resources: onsite staff, medical equipment, and a full bedroom set. Not only is this an additional expense for insurance payers, but the unfamiliar sleep setting can affect the patient’s normal sleep patterns and skew the test results. Expanding the labs to home sleep testing solves many of these problems.

Familiar Environment:

While some extreme conditions still require in-lab sleep testing, many patient populations are well suited for home sleep diagnostic testing. These groups include those tested for occupational reasons, patients with a high probability of sleep apnea, the home bound and those suffering from chronic pain. The unfamiliar in-lab environment can lead to increased anxiety for the patient and inconvenience to those caring for them. For patients with chronic pain who experience difficulty in traveling to a sleep lab. It also is more convenient for the patient’s caregiver who would normally be needed to accompany them during the overnight study. As the desire for home testing continues to grow, new technology will continue to improve diagnostic devices that will increase the reliability of home testing and will expand the number of patients that can be successfully tested in the home. Furthermore, moving a patient who requires a paid medical assistant can be expensive for the patient and/or the insurance payer.

Affordability:

The changing reimbursement and acceptance of home sleep testing by insurance payers and sleep professionals will open up opportunities for improved patient care and will provide sleep labs with a means to expand the reach of their sleep services.

Traditional Sleep Labs Can Expand:

In addition to these benefits for the patients, traditional sleep labs will also benefit from expanding their sleep services to include home testing. Typically overcrowded labs will only have deal with those who require in-lab testing, and they can service a larger total volume of patients since they do not all need to be onsite. Each patient population can then receive a faster diagnosis and therefore faster treatment initiation, without the need for additional beds for the sleep lab. The traditional sleep labs, by incorporating home sleep testing, dramatically improve the care for their patients and the ease of diagnosis for their staff.

Overall, home sleep testing will greatly improve the patient care, and new technologies will continue to improve the quality of at-home care.

This post draws on the experience of several experts at CleveMed and is an adaptation from “Home Sleep Testing Can Improve Patient Care,” by Sarah Weimer, as seen in Sleep Diagnosis and Therapy, January-February 2008

Sleep labs are beginning to take advantage of the added simplicity, patient comfort and cost savings associated with wireless technology. If a sleep lab is considering going wireless, it is important that they have each potential supplier in for an actual run through, and preferably allow a 30-day trial at their facility. Some wireless units, for instance Bluetooth devices, have a limited range and may not be suitable for labs with long hallways without added tools. Anyone who has ever lost a connection on a cell phone knows that wireless technology is not yet flawless. If a PSG study is interrupted several times through the night, typically since the amount of PSG data being transmitted is so large, even brief lapses can disrupt acquisition, annoy sleep techs and may affect data interpretation.

If your sleep lab is considering going wireless here’s an important list of questions you should ask potential wireless PSG equipment supplier:

1. What frequency range does the system operate in?
2. How far can the patient be from the monitoring room?
3. How many devices can we have working at one time without interference (cross-talk) risk?
4. What is the battery life of the device under continuous use? You need to make sure the device can stay on at least a full night. (Wireless technology can consume a lot of power).
5. What happens when there is interference – can the device retransmit data? Can it run a “spectrum sweep” of the environment?
6. How difficult is it to change the operating frequency to move away from the interference?

This post draws on the experience of several experts at CleveMed and is an adaptation from “Wireless Polysomnography” as seen in Sleep Diagnosis and Therapy, June⁄ July 2006.

When opening a new sleep lab, the cost of hard-wiring the rooms can be a significant portion of the cost of the installation. The installation team must work with hospital technical staff, often for a day or even two days before systems are up and running. Cabling must be run and tested.

Wireless Advantages:

On the other hand, wireless devices can transmit data through multiple walls without any cables running through ceiling tiles. There are often less components, meaning easier setup and lower risk of individual component failure. Setups outside of the lab become more feasible. For example, mobile diagnostic studies in hotels, long term care facilities or nursing homes mean that a comprehensive sleep diagnostic service can come to the patient instead of the patient having to come to the lab for a PSG. Hospital networks, wireless or intranets are used to transfer sleep studies from the bedside to the sleep lab. Technicians can monitor and respond to problems, yet the patient is still under the immediate supervision of skilled nurses.

Wireless Not Flawless:

But, anyone who has ever lost a connection on a cell phone knows that wireless technology is not yet flawless. If a PSG study is interrupted several times through the night, since typically the amount of PSG data being transmitted is so large, even brief lapses can disrupt acquisition, annoy sleep techs and may affect data interpretation.

Workarounds:

Wireless systems work by transmitting data via electromagnetic waves at a defined frequency. With so much congestion in the 2.4 GHz band (the most commonly used, from Wireless Local Area Network to microwave ovens), the probability of losing data due to radio frequency interference increases. In order to enhance their immunity to interference, most wireless devices operate in a pseudo-random fashion, a strategy known as “hopping“. Because this signal is not stationary, the approach works well for small and intermittent transmissions, like browsing the internet. Sleep studies however, have large data files that are continuously streaming for hours, which make the process of data recovery more difficult if not impossible. One potential way to mitigate this problem is to simultaneously store the PSG data in memory inside the bed-side unit and use the transmitted data only for basic patient status check and to confirm electrode connections.

Our next post:
Questions that you should definitely be asking your potential equipment supplier if your sleep lab is considering going wireless.

This post draws on the experience of several experts at CleveMed and is an adaptation from “Wireless Polysomnography” as seen in Sleep Diagnosis and Therapy, June⁄ July 2006.