A split night sleep test is an overnight sleep test done in a sleep testing facility. It is usually a planned change in the testing no later than half way through the night. It occurs when a certain level of Obstructive Sleep Apnea is found during the first few hours of the sleep test. On some tests, the night will be split when severe apnea is discovered although it was not planned.
The first few hours of the test is performed to observe and record your usual sleep. Sleeping while wearing the diagnostic monitors may not feel like normal sleep to you, but sleep observed while wearing those monitors is usually representative of your typical sleep. The diagnostic portion of the study will be stopped when a certain level of apnea is observed. You physician usually determines the level of apnea at which the study will be split.
For the remaining portion of the test time, treatment with positive airway pressure will be started and continued through the night of the test. Thus, the first half of the night is used to establish the diagnosis of obstructive sleep apnea while the second half is used to determine how much pressure will be needed to treat the apnea.
The pressure test performed during the second half of the night is called a Positive Airway Pressure titration or more commonly a PAP Titration. A PAP titration is performed to measure the effect of breathing air at a slightly higher pressure. During this stage of the test, the sleep technician monitors your measurements for obstructive apnea and gradually increases the amount of pressure to determine the pressure required to control the obstructions.
A person with sleep disordered breathing problems might be able to be diagnosed and have treatment assessed in one night when a split night test is performed. However, realize that you may still have significant sleep apnea even though you did not have a split night study.
Sometimes a scheduled split night test does not get split. This can occur when no apnea is observed, when the amount of apnea observed does not reach the level required to meet the criteria, or when there was not enough time left in the study to complete the titration.
Page thought –Positive airway pressure treatment is the first treatment considered for apnea because it is the safest most effective therapy for obstructive sleep apnea.