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Sleep Disorders & Study FAQ's for Physicians

Below, we answer some of the more frequently asked questions we receive from physician offices about sleep disorders testing.

Frequently Asked Questions (FAQ's)

Which patients need sleep tests?
In general, patients with likely sleep apnea need a polysomnogram (PSG) to test for sleep apnea and to determine its severity, and often a second PSG for CPAP initiation. Patients with severe sleepiness, who are not chronically sleep deprived and who have no other apparent cause of sleepiness, usually need testing. These patients usually need a PSG to determine whether they have sleep apnea or periodic limb movements of sleep; in addition such patients usually need a Multiple Sleep Latency Test (MSLT) to determine their degree of sleepiness and to determine whether they have sleep-onset REM periods, as do most narcolepsy patients. Patients with insomnia usually need diagnostic testing only if the insomnia has persisted despite more than 6 months of treatment.

Which sleep test should I order?
Polysomnography (PSG) alone is adequate to assess most people with suspected sleep apnea. The Multiple Sleep Latency Testing (MSLT) is used selectively to further evaluate patients for sleepiness and for other sleep disorders.

A split-night study is especially useful after the physician has thoroughly discussed sleep apnea treatment options with the patient, and when the patient has a good idea of the nature, inconvenience and treatment value of CPAP. A split-night study, when successful, allows diagnosis of sleep apnea and treatment with CPAP during a single night. During a split-night study the technologist is instructed to perform a standard diagnostic PSG for at least two hours of sleep. American Academy of Sleep Medicine consensus statements recommend that CPAP be initiated for patients with the following polysomnographic results:

  • An apnea plus hypopnea index of at least 40 per hour, documented during a minimum of two hours of polysomnography.
  • An apnea plus hypopnea index of 20 to 40 if there are repetitive long obstructions and major desaturations, or other documented reason why less than a full night study is warranted.

A split-night protocol may halve the cost of diagnosis and treatment initiation for sleep apnea patients, but it requires that the technologist make the initial diagnosis based on an incomplete recording. Since apneic episodes often are more frequent or more severe during REM sleep, and since REM sleep usually predominates in the latter half of the night, a two-hour initial baseline PSG may underestimate significantly the baseline severity of apnea. The effects of body position on breathing may be missed during an abbreviated diagnostic study, and there may be insufficient time during CPAP titration to be certain that breathing has been corrected in all positions and sleep stages. Despite these limitations split-night studies are a valuable tool to help reduce costs, however, insurance approval is required.

Some patients may sleep poorly in the sleep center, and they may not complete two hours of sleep until three, four or more hours have elapsed. CPAP will not be started for those patients, since there is not time enough left to allow a complete and accurate determination of the best CPAP treatment pressure. Some patients have mild sleep apnea, but still may benefit from CPAP treatment. We do not start CPAP if the RDI is below 20-40/hour during the baseline, partly because those patients may choose alternate treatment such as dental appliance therapy, and partly because a half-night study may miss the most severe apneic episodes occurring later in the night.

Should patients take their usual medicines before sleep testing?
Many medications such as antidepressants and benzodiazepines, may change the natural sleep structure; on the other hand, let's remember that the sleep test itself usually changes the natural sleep structure. Antidepressants may worsen snoring, sleep apnea and PLMS. Benzodiazepines may worsen snoring and sleep apnea, but they may improve PLMS. In general, since the referring physician wishes to answer a clinical question about a patient's sleep under their daily conditions, we usually recommend that patients take all their daily medications before sleep testing.

Alcoholic beverages may worsen snoring and sleep apnea, and many patients routinely drink several each night. We do not allow alcoholic beverages in our facilities, and we do not encourage patients to drink them before driving to our centers.

If a patient has very significant insomnia at home but requires testing for possible sleep apnea, then we often prescribe a short-to-medium duration hypnotic medication. The patient fills the prescription at a pharmacy, brings it to the sleep center, and takes it after arrival. In this case the patient may need a ride home in the morning. The referring physician weighs the small possibility that medications may affect sleep stages and respiration, against concerns that the testing may not be diagnostic if the patient does not sleep long without the medication.

How will my patient learn their sleep testing results?
We expect that the patient will learn the results as they would learn the results of any diagnostic procedure, such as an imaging study, serum testing, or genetic screening test. We will report the results to your office, and we encourage the patient to contact you. If a patient specifically requests a copy of the sleep testing report, we provide one.

How do I make a referral to one of the sleep centers?
To make a referral to Greater Washington Sleep Disorders Centers, please complete the order form on behalf of the patient you are referring and fax it directly to 301-251-1707. To obtain more order forms please call 1-AWAKEN1 (800-292-5361).

Typically what is the wait time for patients to be scheduled?
Patients usually can be scheduled within one to two weeks. Patients are scheduled for the first available appointment.

What insurances are accepted by the centers?
We accept Medicare and most other indemnity and managed care insurance payments, and those plans usually pay between 80 to 100 percent of the test costs. Please call us directly at 1-800-AWAKEN-1. (1-800-292-5361) to verify that we accept or participate in your patient's plan.

Will Medicare pay for CPAP?
Under a new 2002 policy, CMS approves CPAP payment for patients with an apnea/hypopnea index (AHI) of 15 or more, and for patients with an AHI of 5-14 with documented symptoms of excessive daytime sleepiness, impaired cognition, mood disorders or insomnia, or documented hypertension, ischemic heart disease or history of stroke. The AHI is equal to the average number of episodes of apnea and hypopnea per hour and must be based on a minimum of 2 hours of sleep recorded by polysomnography using actual recorded hours of sleep (i.e. the AHI may not be extrapolated or projected). Apnea is defined as a cessation of airflow for at least 10 seconds. Hypopnea is defined as an abnormal respiratory event lasting at least 10 seconds with at least a 30% reduction in thorocoabdominal movement or airflow as compared to baseline, and with at least a 4% oxygen desaturation. The polysomnography must be performed in a facility-based sleep study laboratory, and not in the home or in a mobile facility.

The specific policy wording is important. For patients to have coverage for CPAP, their diagnostic tests must be polysomnography with sleep staging, not sleep studies that measure only cardiopulmonary data, and split night studies must include a baseline of 120 minutes of recording. Most sleep centers have adopted the Medicare hypopnea definition for all patients, since it is almost impossible to use separate scoring rules only for Medicare patients. To reduce difficulty for the patient, DME provider and prescribing physician, our reports clearly state the AHI and a summary of patient symptoms.

Patients can be referred to the Free CPAP Clinic for desensitization. Call 410-787-4768 for an appointment.

What if patients who need CPAP do not qualify for insurance coverage?
There are some patients who benefit from CPAP for sleep-disordered breathing, but who do not meet the Medicare or private insurer coverage criteria. For example, some patients have very frequent arousals because of increased breathing effort, but do not have desaturations. Those patients will have a high respiratory disturbance index (RDI), but they may have a low number of apneas and hypopneas - their apnea/hypopnea index (AHI) will be low. Patients with upper respiratory resistance syndrome (URRS) - a type of sleep-disordered breathing - have a low AHI and also may have a low RDI. On CPAP these patients may have very significant improvement in sleep continuity and in alertness, but they may not qualify for CPAP coverage by Medicare criteria.

We cannot alter the medical data to meet the coverage requirements; we do ask Medicare patients in this situation to write to their Congressional Representatives and Senators to protest that the coverage requirements are too strict and do not allow for clinical exceptions. We advise privately insured patients to apply for coverage waivers.

How does the interpreting sleep doctor determine which CPAP pressure to recommend?
When we initiate CPAP during a polysomnogram (PSG), we raise CPAP pressure to eliminate apneas, hypopneas, desaturations, and snoring. The lowest pressure that eliminates all these events is the pressure we recommend for home CPAP. At too low a pressure, snoring or sleep-disordered breathing may persist; at too high a pressure, patients may tolerate CPAP less well, and central apneas may appear. Because tested pressures range from a low of about 4 cm H2O to a high of about 20 cm H2O, with many steps in between, the patient may sleep only a short time at each of a number of pressures, and the interpreting physician then may recommend a pressure that was effective at relieving sleep apnea when the patient was sleeping supine, during REM, when sleep disordered breathing is expected to be worst for many patients. Depending on clinical factors during treatment, the treating physician may adjust the CPAP pressure higher or lower than was originally recommended.

Commercial FDA-approved devices deliver CPAP pressures reliably as prescribed. The choice among machines is dictated by appearance, by associated features such as heated humidifiers on some machines, and by the brands carried by the durable medical equipment company which contracts with the patient's insurer.

What if the CPAP titration study fails, or if the sleep apnea is treated by CPAP, but the patient does not tolerate it well?
In one study, full-night CPAP titration failed on 16% of nights to find an effective CPAP treatment pressure, and the failure rate is higher for split-night studies - so this is a common problem. Without enough data to determine a likely effective pressure, the interpreting physician may recommend repeat testing; for example, if a patient did not sleep much with CPAP, a repeat test may be very helpful after the patient has taken a prescription hypnotic medication.

Several studies have demonstrated that many patients can be helped by CPAP even though the titration study is not perfect. In such cases, the interpreting physician may recommend a CPAP starting pressure, and may recommend repeat CPAP titration after the patient has become accustomed to using CPAP.

Will the sleep center order CPAP for my patient?
CPAP prescription requires a physician order. Sleep center physicians order CPAP on patients we have evaluated in consultation, after discussing the cause and medical complications of sleep apnea and alternative treatments. When we have not evaluated the patient in consultation, but rather have only interpreted a study, we do not order medication, surgery, dental appliance, or CPAP therapy.

How do I instruct my patients to get used to CPAP?
Long-term compliance with CPAP can be improved with good patient education and coaching. After using CPAP in the sleep center, about 70%-80% of patients accept a home trial. Those patients who will use CPAP usually develop a compliance pattern within the first 4 days. Of those using CPAP, 90% are still using it after 3 years and 85% after 7 years. Those who give up, usually do so within the first few months. In our practice we almost always prescribe a 20-minute ramp to full pressure, a baffle humidifier, a second CPAP mask as soon as possible, and gradual CPAP desensitization for all patients, after a method proposed by Edinger and Radtke:

  • STEP 1: Wear the CPAP mask or nasal pillows at home while awake in the evening and performing normal evening activities, for about one hour daily. When you can do this without anxiety or concern for several days, or up to five consecutive days, and then go to Step 2.
  • STEP 2: Connect the pressure device and tubing to the CPAP pressurize, at the pressure prescribed by your doctor. Turn on the machine, and breathe through it at home and at rest, for one hour daily. When you can do this without anxiety or concern for up to five consecutive days, and then go to Step 3. When you are getting used to CPAP in Step 1 and Sept 2, practice putting on the mask with your eyes closed. Experience how the pressure ramps up. Practice moving your head at full pressure, to get used to the mask leak and how to stop it. Let your bed partner and family members touch the CPAP so they are not afraid of it! Remember: CPAP is just pressurized air, not oxygen, so it isn't dangerous, and it won't blow up!
  • STEP 3: Wear the entire CPAP apparatus for a scheduled one-hour nap. When you can do this without anxiety or concern for five consecutive days, and then go to Step 4.
  • STEP 4: Wear the entire CPAP apparatus for 4-5 hours of sleep each night.  When you can do this without anxiety or concern for five consecutive days, and then go to Step 5.
  • STEP 5: Use CPAP for your entire night's sleep.

When patients have had no difficulty using CPAP in the laboratory, we recommend beginning at Step 2, then progressing quickly to Step 5. Call us for copies of general recommendations to patients about CPAP use and travel.

What if my patient still cannot use CPAP?
About 50% of patients, who fail CPAP initially, will still be able to use positive airway pressure. Try these steps:

  • Review the CPAP polysomnogram to determine whether lower pressures were effective in the laboratory.
  • Switch from Continuous PAP (CPAP) to Bilevel PAP (BiPAP). When starting BiPAP without a separate titration night for patients who have failed CPAP, we usually set the BiPAP inspiratory pressure at the prescription CPAP pressure, and set the expiratory pressure 4-6cm H2O lower.
  • Be sure the patient is using a humidifier. Consider using a heated humidifier, which is more effective for a small number of patients.
  • Switch to a different mask size or style.
  • Consider a trial of a prescription hypnotic medication to be taken before the PAP device is placed.
  • Consider measures to improve nasal potency, such as using a nasal steroid spray and oral decongestant agents.
  • Restart the desensitization program, as outlined above.

How does the dental appliance work for sleep apnea? When should I prescribe it?
Airway dilators (also referred to as dental devices or oral appliances), originally developed to correct occlusal disorders, have been approved by the FDA to treat sleep disordered breathing. These devices, inserted intraorally at night, anteriorly displace the mandible and tongue, enlarging the retroglossal space and reducing upper airway obstruction. The airway dilator can be constructed in a laboratory from impressions prepared in a dental office. Airway dilator treatment is generally well tolerated, safe, reversible and cost effective.

A task force of the American Academy of Sleep Medicine (AASM) has recommended that oral appliances are indicated for patients with primary snoring or mild OSA who do not respond to behavioral treatments or who are not appropriate candidates for behavioral treatments. The task force also recommended that oral appliances are indicated for patients with moderate to severe OSA who fail or refuse CPAP or surgical treatments (An American Sleep Disorders Association Report. Practice Parameters for the Treatment of Snoring and Obstructive Sleep Apnea with Oral Appliances. Sleep 18: 511-513, 1996). An AASM task force is reviewing this practice parameter during 2003-2004. Airway dilators should be prescribed cautiously in patients with temporomandibular joint (TMJ) dysfunction, dental complications such as bridges or implants, and bruxism.

A number of dentists fit and supply airway dilators in their offices, but patients may have difficulty arranging insurance coverage.

What is the difference between restless leg syndrome (RLS) and periodic limb movements of sleep (PLMS)?
RLS occurs in waking patients, and PLMS occurs in sleeping patients. Up to 10% of people experience a restless feeling, particularly in the legs, which usually becomes bothersome during the late evening hours. Patients describe numbness, cramping, or other symptoms, which improve when they move their legs. These symptoms often interfere with sleep onset and often lead to long awakenings after sleep onset. About 10% of people may have regular, repeated, uncontrollable leg jerks as they sleep, and the resulting arousals disturb sleep. Most people with RLS or PLMS have both disorders, and medical treatment usually is effective.

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