A Polysomnogram is a common overnight sleep test that physicians often prescribe to patients that are suspected to have or are already known to have sleep disorders. The polysomnogram, often called a PSG measures and records activity during sleep. The PSG monitors many body functions including brain activity, chin and leg muscle activity, respiratory airflow, heart rhythm, eye movements, blood oxygen saturation and more during sleep. Polysomnograms are used to diagnose or rule out a wide range of sleeping disorders including sleep disorder breathing issues like sleep apnea, hypersomnia disorders like narcolepsy, circadian rhythm disorders like shift work sleep disorder and delayed sleep phase syndrome, movement disorders like Periodic Limb Movement Disorder, insomnias, parasomnias, and other sleeping disorders. It is important to remember that a polysomnogram is a not a test, but instead a painless, in-depth recording of how well you sleep. The polysomnogram will also reveal the severity of the disorder and give the physician guidance to the proper treatment to prescribe.
There are many variations to the Polysomnogram that can also be performed, such as with the use of supplemental oxygen for those known to have hypoxemia, with the use of a dental appliance used to advance the lower jaw forward, and when a patient has an existing trach that bypasses the upper airway and desires to have it removed but needs to evaluate the airflow through the upper airway when closed at night before performing the surgery to close up the hole.
One of the most common variations to a full night Polysomnogram is the “Split-Night” Polysomnogram. In a “Split-Night” sleep study, the first half of the night is performed as a diagnostic sleep study and the second half of the sleep study is performed with the use of Positive Airway Pressure, like CPAP. The technologist must follow a very specific protocol outlined by the sleep center’s supervising physician and may not be able to initiate the split if the conditions were not met in the first half of the Polysomnogram. Although “Split-Night” studies limit the amount of data collected for the reading physician there are times when such a study would be beneficial, such as in the event that significant or profound sleep disordered breathing is observed within the qualifying conditions.
Polysomnogram with Positive Airway Pressure (PAP)
If the results of your polysomnogram test reveal that you have sleep apnea, your doctor may recommend that you have a CPAP Titration. The CPAP Titration is identical to a polysomnogram with the addition of a medical device known as a continuous positive airway pressure machine (CPAP). This machine blows pressurized air into just the nose or nose and mouth at the same time via a mask in order to eliminate the snoring and pauses in breathing that sleep apnea produces.
The CPAP Titration is an overnight sleep study used to determine the most effective airflow setting for your CPAP machine, measured in centimeters of water or cmH2O. The test also ensures that you have been given an opportunity to be educated about how it works, desensitize you to the pressure and ensure that the right mask is chosen so that it will produce the best possible results while using it at home. CPAP Titrations are also often recommended for those who have been using the same CPAP machine on the same setting for over a year.
If you are current CPAP user, it is often beneficial to have yourself re-evaluated and/or your pressure settings re-titrated if you do not feel that it is still helping you sleep better at night and feel better during the day. Many insurance companies will also require you to be re-evaluated before approving the purchase of a new machine if it has been over a year since your last Polysomnogram. You may want to call your insurance carrier to see if such a requirement exists for you.
There are also variations in Positive Airway Pressure devices. The most common is Continuous Positive Airway Pressure, also called CPAP, and delivers a constant and continuous pressure while you breath in and breath out on the device. Another, more sophisticated device is called Bi-Level Positive Airway Pressure, often called BiPAP, and delivers two different pressures; a higher pressure while you breath in and a lower pressure while you breath out. This approach generally allows for greater comfort and compliance to those that have difficulty with CPAP. Most insurance will require evidence that CPAP was not effective or that you had issues using it before allowing BiPAP treatment.
In some instances, an auto-titrating device called Auto-PAP may also be prescribed for some people who tolerate CPAP well but may need different pressures in different stages of sleep or positions of sleep.