lung and airway disorders
Sleep Apnea
Diagnosis of Sleep Apnea
Doctor's evaluation Polysomnography Sleep apnea is suspected on the basis of the person's symptoms. Sometimes doctors use questionnaires to help screen for symptoms, such as excessive daytime sleepiness, which may be due to obstructive sleep apnea. The diagnosis is usually confirmed and severity is best determined by monitoring the person's breathing during sleep. The first step is usually monitoring at home with portable equipment that the person wears for several nights. This equipment can monitor breathing, heart rate, airflow through the nose, and oxygen levels. A more thorough test can be done using a polysomnography, during which the person sleeps overnight in a sleep laboratory. This evaluation can help doctors distinguish between obstructive and central sleep apnea. Inpolysomnography: Electroencephalography (EEG) is used to monitor the person's brain waves to detect changes in levels of sleep and eye movements. Oximetry, in which an electrode is placed on a fingertip or an earlobe, is used to measure the level of oxygen in the blood. Airflow is measured with devices placed in front of the nostrils and mouth. Motion and pattern of breathing are measured with a monitor placed around the chest. The sleep tests determine theapnea-hypopnea index(AHI). The AHI represents the average number of episodes of nonbreathing (apnea) and decreased breathing (hypopnea) occurring per hour of sleep time. The more events that occur, the more severe the sleep apnea and the greater the likelihood of adverse effects. Doctors use the AHI plus the person's symptoms to diagnose sleep apnea. Sometimes additional testing is needed to help doctors determine the cause. People with sleep apnea may be tested for complications, such as high blood pressure and atrial fibrillation. If doctors suspect central sleep apnea, testing may rarely be needed to determine the cause. 