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Split Night

Sleep Study

What is it?

A Split night study is a combination of a Diagnostic study and a Titration study. It is performed when a pt shows signs of severe Obstructive Sleep Apnea. You would be started as a Diagnostic Sleep Study and if you show enough Obstructive Sleep Apnea events ( Apneas are total airway collapse, Hypopnea’s  are partial airway collapse) within the first 2 hours of sleep ( emergency setting would  show symptoms of more than 20 events or more of airway or partial airway collapse per hour). You would  be started on the treatment portion of the Sleep Study  which is called a Titration(using Cpap)  Some Physicians will also order a Split night Polysomnogram if they feel that the patient might be severe enough to warrant immediate treatment

Who gets it?

A Split night Polysomnogram is often used in the following cases:

  • To look for sleep-related breathing disorders, such as sleep apnea that might be severe (over 20 times per hour)

  • To set the correct levels of continuous positive airway pressure (CPAP) in patients with sleep related breathing disorders


Your doctor will want to order a Split night 0-0olysomnogram if he or she thinks you have any of these problems. You might also have a sleep study if you are already being treated for a sleep disorder but you are not getting better. The sleep study can help your doctor see why the treatment is not working.

What happens when I have it?

The technicians at the sleep center will go out of their way to make you feel relaxed. You will be asked to come to the center in the evening. Some time will be given for you to make yourself at home in the bedroom. No other patients will be in the room with you.

You will not feel any pain during the polysomnogram. The sensors are gently placed on your skin and connected to a computer. The wires are long enough to let you move around and turn over in bed. You will be asked to move your eyes, clench your teeth and move your legs. This will make sure that the sensors are working.

You are free to read or watch TV until your normal bedtime. Then the lights are turned out and it is time for you to try to fall asleep. A low-light video camera allows a technologist to see you from a nearby room. He or she will have to enter your room if a sensor comes loose. He or she will also have to detach the wires if you need to go to the bathroom during the night.

The Split night Plysomnogram is not a test that you can fail. Nearly everyone falls asleep during the study. Most people do not sleep as well as they do at home. This will not affect the results. In most cases, you do not need to sleep for a full eight hours to find the source of your problem.

In the morning you will test the sensors again, and then they will be removed. This will complete the study, and you will be free to go. You can return to normal activities on the day after a sleep study.

Who reads it?

A technologist is the first one to look over the data from a sleep study. First, he or she will chart your sleep stages. Then, he or she will look for any events of abnormal breathing or leg movement. The results will be given to a doctor. The doctor will review the study to find out what kind of sleep problem you may have and what treatment level was beneficial.


Occasionally you might have to return for further treatment as time can run out before the technicians can obtain an optimal pressure setting, or you might need more involved therapy options.

Many sleep centers are accredited by the American Academy of Sleep Medicine (AASM). The AASM sets strict standards for centers to maintain. This is to make sure that patients with sleep disorders get the highest level of care. In these centers, the results of a sleep study are always reviewed by a board-certified sleep specialist.

How do I get the results?

It usually takes about two weeks to get the results of a sleep study. At times the doctor who takes a look at the study needs to get more information. He or she may talk to the technologist or to the doctor who sent you to the center.

The Sleep Physician will discuss the results with you. Your Physician who ordered it, will have the results sent to him or her.

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