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Sleep Center FAQs

Frequently asked questions about Sleep Centers

How do I get to the sleep lab/clinic?

What is a Sleep Study?

Sleep Study (Polysomnogram)

Sleep studies (polysomnograms) generally take place in a sleep lab during a person's normal sleeping period. The study records brain waves, breathing and and body activity that occur during sleep with the purpose of diagnosing and treating various sleep disorders.  A trained sleep technician will be with you in the sleep lab during the testing period. Physicians trained in sleep medicine evaluate test results to determine a course of action and resolve sleep related issues.

What is recorded in a sleep study?

The term "polysomnogram" indicates that there are multiple tests in a sleep study. Various body activities and indicators may be measured during a sleep study. Measurements may include:

  • Eye movements- to identify wake and different stages of sleep  
  • Brain activity (EEG)  - electrical currents of the brain
  • Limb movement - number and intensity of movements
  • Breathing patterns - number and depth of respirations. A sensor is placed by the nose and mouth for measurement of airflow. Belts are placed around the rib cage and abdomen for measurement of breathing movements.
  • Heart rhythm (ECG) - electrical activity of the heart
  • Oxygen saturation - percentage of oxygen in the blood
  • Sleep latency - time it takes to fall asleep
  • Sleep duration - period of time a person stays asleep
  • Sleep efficiency - ratio of the total time asleep to the total time in bed

Why do you need a sleep study?

Various sleep disorders can cause problems with sleep. Common reasons for a sleep study include:

  • excessive snoring
  • sleep apnea (periods where the breath stops during sleep)
  • daytime sleepiness
  • narcolepsy (sudden onset of sleep)
  • insomnia (inability to sleep)
  • abnormal movements during sleep- including kicking legs during sleep, sleepwalking, epilepsy, abnormal acting out of dreams etc.
  • There may be other reasons for your physician to recommend a sleep study.

Are there any risks with the procedure?

There are no known risks for a sleep study other than possible skin irritation due to the attachment of the electrodes to the skin.

Before the Procedure

  • Your physician will explain the procedure to you and offer you the opportunity to ask questions.
  • You will be asked to complete a sleep questionnaire or sleep diary to be completed ahead of time.  Do your best to provide the most accurate responses.
  • Please remember to bring any medical records and reports (such as sleep study report, notes from other physicians, etc)
  • You may be asked to restrict your sleep before the study, avoiding naps for example.
  • Notify your physician of all medications (prescription and over-the-counter) and herbal supplements that you are taking, as they may alter test results.
  • Avoid caffeine-containing products for several days before the testing as they may cause you to take longer to fall asleep.
  • Sedatives may not be allowed during the sleep study, unless prescribed by the sleep physician, as they can alter the results.
  • Showering before going to the sleep lab may be helpful; however, avoid using lotion or oil on your skin because the electrodes may not adhere to the skin.
  • You may bring your own pajamas and pillow.
  • If needed, you may be able to shower and dress for work the morning after the sleep study.
  • Based on your medical condition, your physician may request other specific preparation.

During the Procedure

A sleep study is generally performed on an outpatient basis at night. Procedures may vary depending on your condition and your physician's practices.

Generally, a sleep study follows this process:

  • You will be asked to remove any jewelry or other objects that may interfere with the procedure.
  • You will be asked to change into pajamas or a hospital gown.
  • Small metal discs, or electrodes, will be positioned on your head and body to measure EEG, ECG, eye movements and leg movements.
  • Pulse oximetry, which measures the oxygen level in the blood vessels, and air flow monitors, which measure breathing, will be applied to the finger and face, respectively.
  • The temperature of the room may need to be maintained at a certain level, but blankets can be adjusted as needed.
  • Lights will be turned off and monitoring will begin before you fall asleep.
  • For multiple sleep latency testing (MSLT), five short daytime nap periods will be assigned at specific intervals, following the previous night’s sleep study.
  • For multiple wake testing (MWT), you will be asked to try and stay awake for certain periods of time during the day.
  • When the study has been completed, the electrodes and other devices will be removed.
  • On certain occasions, you may be required to follow-up in the sleep clinic the day after your test.
  • CPAP study: For some patients who have sleep apnea, the effects of continuous positive airway pressure (CPAP) are evaluated. Patients, who have been diagnosed with sleep apnea during the initial part of the sleep study or on a prior sleep study, undergo a CPAP study. During the CPAP study, a mask is fitted around the nose and pressurized air is used to keep the airway open during sleep. The pressure level that holds the airway open during sleep and allows the patient to get a good night's sleep is the prescribed CPAP pressure.

After the Procedure

  • The results of the study may take several days to process.
  • The results and specific recommendations will be forwarded to your referring physician through the VA electronic computer record keeping system.
  • If you have obstructive sleep apnea, you will be notified by the respiratory therapist at your local VA Medical Center to pick-up your CPAP machine and receive training on how to use the machine.
  • Follow-up care will be arranged by the VA Medical Center or clinic near where you live.
  • Patients may also be scheduled for follow up at the Sleep Disorder Center in Detroit after installation of CPAP. Patients should bring their CPAP machine, mask and compliance card with them for the follow-up visit.


What preparations do I have to make before the study?

What is CPAP?

A continuous positive airway pressure (CPAP) machine is a mechanical device used as an effective mode of treatment for sleep apnea. The CPAP machine blows air at a prescribed pressure by delivering a stream of compressed air via a hose to a nose mask, nasal pillow or full-face mask, splinting the airway (keeping it open under air pressure) so that unobstructed breathing is possible during sleep. This eliminates Sleep Apnea and allows the patient to get a restful sleep and improve blood pressure. Many factors can affect your ideal pressure over time, like weight fluctuations and even sleeping positions.

CPAP or Bi-Level Positive Airway Pressure (BPAP) devices are also referred to as PAP (Positive Airway Pressure) devices.

When should I start feeling better after beginning to use my PAP?

Most patients begin feeling better within the first two weeks, though some patients may take a little longer.

Why is it hard to breathe out against the air flow?

This sensation will improve over time as you adapt to the therapy. If it does not then call your respiratory therapist.

Why do I have trouble falling asleep on PAP or feel uncomfortable when I first apply the air pressure at night? What should I do?

This is a common experience for first time CPAP users. It improves over time. You can turn on the ramp feature that is available on your PAP device. Use this feature to slowly raise the pressure to your prescribed pressure setting. But use it only when trying to fall asleep in the beginning of the night or after putting the mask back on if it was taken off for some reason. Overusing this feature may be detrimental for your sleep disorder.

Why can't I seem to adjust to using CPAP?

Most people will adjust to CPAP in about four to six weeks. Occasionally, it may take a little longer if, for example, you are very sensitive to the feel of the mask on your face or the sound of the device. Call the respiratory therapist at your VAMC if you are having problems adjusting to the treatment.

What if I still snore on PAP?

Snoring while on PAP should not occur. If it does, contact your doctor or respiratory therapist. Your mask may need to be adjusted, or there may be a leak through the mouth or the pressure level may need to be adjusted.

What if I lose or gain weight or my old symptoms reappear?

You may need to have your PAP pressure level adjusted if you lose or gain about 10% of your usual weight. Contact your primary care doctor.

My skin seems irritated, even bruised, or I have marks on my face?

Your mask may be too tight. If your mask has a forehead arm or adjustment feature try readjusting that first. Then, if necessary, readjust the headgear straps. It is possible that you may have the wrong mask size. Consult your VA respiratory therapist if the problem persists.

As I continue to use my PAP on a regular basis, will my medications need to be adjusted?

Please do not alter your medications without consulting your doctor. Discuss with your doctor if you are taking any sedating medications as these can worsen sleep apnea. DO NOT USE SEDATING MEDICATIONS IF YOU HAVE SLEEP APNEA.

If I need to be hospitalized for any reason, should I take my device with me and use it at night?

Yes. Also, if you are having surgery, it is important to tell the surgeon and the anesthetist that you are using a PAP at home. You should also inform the doctor treating you for sleep apnea that you are going into the hospital.

Should I use my PAP when I travel?

It is important that you use your PAP every night. Purchasing travel accessories will make it more convenient for you to travel with your PAP. Because of increased security measures at airports, it may be easier to travel if you have a copy of your prescription for your PAP machine with you. Call your airline ahead of time and ask if there is a special screening procedure required to carry on or check your PAP device.

How can I tell when my mask is worn out?

Inspect your mask for stiffness, cracks, or tears. You can get a replacement every six months, if necessary.

Air seems to be leaking around my mask. What should I do?

Check all the connections. If your mask has a forehead arm or adjustment feature, try readjusting that first to correct the leak. If there is no improvement with the above steps, readjust the headgear straps. The mask should be loose while still creating a seal. A mask that is too tight against the face can cause leaks to occur by creating folds in the material. Try another mask size or type if necessary.

My mask seems dirty. What should I do?

Wash your mask daily with a mild detergent. Dirty mask can lead to infections.

When should I change the mask to a new one?

Contact your respiratory therapist after about six months to change your mask. Contact your respiratory therapist anytime that your mask is worn out or is leaking air. You may need a replacement mask or may need to be refitted with a new mask.

It doesn’t seem as though enough air is flowing to me. Why is that?

Check that air from the machine is blowing. Check the air inlet and filter for obstruction or dust buildup. Check the hose for punctures. If you are still having problems, check with your respiratory therapist for assistance.

Why does my nose and throat feel dry? Why is my nose congested? Why do I have nosebleeds?

Try nasal saline spray before bedtime and upon awakening. Try adding heated humidification. (You will need to ask your doctor for a prescription.) You may change the temperature setting on the humidifier. Consult your doctor if symptoms persist.

My mouth is dry after using the PAP. What should I do?

You may be sleeping with your mouth open. Try a chin strap. If a chin strap is not helpful, a full face mask may be considered or you should consult with your respiratory therapist about adding heated humidification.

Why are my eyes are sore, dry, irritated, or swollen?

Air may be leaking into your eyes. Try pulling the mask away from your face and repositioning it. The mask may be too tight. Readjust headgear straps. Use the forehead adjuster, if applicable, to reduce leaks.

Why do I feel I feel gassy and bloated when I wake up in the morning?

Try sleeping with your head elevated. Try using a chin strap to prevent mouth breathing. This condition may improve over time. If it does not, then contact your respiratory therapist.

Why does the PAP hose fill up with water at night?

Condensation builds up because the air in the room may be cooler than the air coming from the machine. To prevent this condensation from forming, try placing the tubing under the covers to warm it. Drain out the moisture. Keep the CPAP machine at a lower level so that water does not enter the machine.

My machine does not seem to be working. What should I do?

Check the power cord to be sure it is firmly inserted into the back of the machine and the electrical outlet. Contact your respiratory therapist if you have any problems that you are unable to correct. Do not attempt to repair the blower unit yourself.

How should I maintain the machine mask?

CPAP filters should be replaced every 2-3 months. CPAP masks should be replaced every six months. Sinus infections and nasal congestion often result from the failure to replace disposable equipment regularly.

How do I care for my mask?

Masks should be washed daily in warm water with soft soap and left to air dry.

How do I care for the CPAP humidifier?

Change the water in the humidifier every day. Fill it with distilled water, not tap water.

What is a smart card?

A smart card is used to store data from the CPAP that can be downloaded to the computer.