> What is OSA?

> Symptoms

> Morbidity

> Diagnosis

> Treatment


Historically, OSA has been diagnosed by polysomnography in a dedicated sleep lab. To accomplish this, patients are asked to travel to the sleep lab at night and go to sleep in an unfamiliar bed, where electrodes and wires are attached to almost every part of the body to measure:

• Brain activity (electroencephalogram [EEG])
• Eye movement (electrovulogram [EOG])
• Muscle activity (EMG)
• Heart rate and rhythm (electrocardiogram [EKG])
• Respiratory effort (using chest bands)
• The percentage of oxygen and carbon dioxide in your blood

Many patients have to wait weeks to be tested at a sleep lab.The test itself is costly. A significant number of patients are either unwilling to be tested in such an environment or fail to fall asleep even when they are tested.

Over the last few months, major insurers and Medicare have approved home sleep testing for the diagnosis of OSA. There are many innovative testing solutions on the market that non-invasively monitor multiple patient channels often with some combination of finger probes, nasal cannulas, and belts that measure respiratory movement. These can be done overnight in the comfort of one's own home. The results are run through a computer algorithm and analyzed once the testing unit is returned.

Multiple variables are measured to determine whether a patient actually has obstructive sleep apnea. The most common variable that is utilized is the AHI which is equal to the average number of episodes of apnea and hypopnea per hour of sleep. A patient is diagnosed with OSA if their AHI is greater than or equal to 15 events per hour with a minimum of 30 events or if their AHI is greater than 5 and less than 15 events per hour with a minimum of 10 events. At least one of the following is also met:

• Excessive daytime sleepiness (documented by either Epworth greater than 10 or Multiple Sleep Latency Test (MSLT) less than 6)
• Documented symptoms of impaired cognition, mood disorders, or insomnia
• Documented hypertension (systolic blood pressure greater than 140 mm • Hg and/or diastolic blood pressure greater than 90 mm Hg
• Documented history of stroke
• Greater than 20 episodes of oxygen desaturation (i.e., oxygen saturation of less than 85%) during a full night sleep study, or any one episode of oxygen desaturation (i.e., oxygen saturation of less than 70%).