Obstructive Sleep Apnea - OSA

Diagnosis and Treatment of a Nocturnal Breathing Disorder

Obstructive sleep apnea is a problem with breathing and sleeping that can have serious consequences.

Obstructive sleep apnea (OSA) is the cessation of breathing during sleep due to a partial or complete collapse of the upper airway. It is an increasing problem that occurs in approximately 2 to 10% of adults. Fortunately, it can be evaluated and treated to prevent further complications.

Causes

A common factor for OSA is obesity, because the accumulation of fat in the neck makes the upper airway flabby and prone to collapse. A variety of other anatomical factors can lead to OSA, including but not limited to a posteriorly displaced jaw (retrognathia), a small jaw (micrognathia), an enlarged tongue base, an elongated palate, tumors, and swollen tonsils. Other causes are nonanatomical, such as alcohol and sedatives that relax upper airway muscles.

Clinical Manifestations

While asleep, a patient with OSA may have loud snoring, breathing cessation (apnea), and/or sudden awakening due to choking or gasping. He or she may often be unaware of these symptoms unless a bed partner is present to witness them. After waking up, the patient may experience excessive daytime sleepiness, impaired concentration, and fatigue, which increase the risk of serious and fatal accidents, especially those involving motor vehicles.

In the long term, OSA leads to increased blood pressure in the lung circulation (pulmonary hypertension) because small lung arteries clamp down in the absence of oxygen. OSA also causes right-sided congestive heart failure and high blood pressure in the rest of the circulatory system (systemic hypertension).

Diagnosis

A clinician considers the diagnosis of OSA when a patient history reveals the characteristic symptoms of OSA and a physical exam presents possible risk factors for OSA. The diagnosis is confirmed with a sleep study, also known as a polysomnography. This procedure involves the patient sleeping overnight at a clinical facility with collection of various data, including but not limited to apnea, slow breathing (hypopnea), rapid eye movements, seizures, and blood oxygen saturation.

OSA is measured by the apnea-hypopnea index (AHI), which is the total number of episodes of apnea and hypopnea divided by the number of hours of sleep. OSA occurs when the AHI is at least 5. Moderate OSA is defined as an AHI of at least 15, and severe OSA is characterized by an AHI of at least 30.

Treatment

To correct disordered breathing during sleep, the patient wears a nasal mask connected to a continuous positive airway pressure (CPAP) machine. The CPAP machine works by constantly delivering air into the upper airway to keep it open and prevent apneic episodes. Oral appliances to keep the jaw and tongue forward are another option.

In the long term, however, these options are not a substitute for addressing the underlying cause. The patient must still refrain from alcohol and sedatives, lose weight if he or she is obese, undergo surgical uvulopalatopharyngoplasty (UPPP) for anatomical abnormalities of the airway, and have other treatments as needed.