March 2019, Volume XXXII, No 12
Obstructive sleep apnea
Examining the adverse consequences
bstructive sleep apnea (OSA) is a common sleep disorder affecting at least 25 million adults in the U.S. Those at increased risk for OSA include males; post-menopausal women; overweight/obese individuals; and patients with larger neck circumference and crowded oropharynx, positive family history of OSA, and use of sedative hypnotics. Associated chronic medical conditions (e.g., atrial fibrillation, heart failure, diabetes mellitus, stroke, or obesity) also increase risk for OSA. There has been a rise in numbers over the last few decades in association with the obesity epidemic.
Untreated OSA is associated with adverse consequences, including cardiovascular and cerebrovascular complications such as hypertension, coronary artery disease, heart failure, arrhythmias, and stroke. Individuals often suffer from impairments in vigilance, concentration, and cognitive function. Evidence shows that there are higher rates of job-related and motor vehicle accidents due to excessive daytime sleepiness related to untreated OSA. People often experience a decline in their mental health, resulting in increased mood disorders such as depression, which are often more refractory to treatments with untreated OSA. There is also evidence that OSA is associated with metabolic dysregulation, affecting glucose control and risk for diabetes.
Obstructive sleep apnea is characterized by repetitive episodes with cessation of breathing (apneas) or partial upper airway obstructions (hypopneas). This narrowing of the upper airway results in increased breathing effort and impaired normal ventilation during sleep. These events are often associated with reduced blood oxygen saturation. Five or more respiratory events (apneas, hypopneas, or respiratory effort-related arousals/RERAs) per hour of sleep are required for diagnosis of OSA. The severity of the apnea is determined by the frequency of airway obstructions per hour (<5=normal, 5–15=mild, 15–30=moderate, >30=severe).
Patients who report sleep-related concerns—excessive snoring, frequent insomnia, or fatigue during the day—to their primary care doctor are often referred to a specialist in sleep medicine. These specialists may include neurologists, otolaryngologists, pulmonologists, dentists, and other physicians with additional training in the field. Neurologists can identify neurological issues that may affect sleep, as well as long-term risk of dementia and other conditions. Primary care doctors should follow up with these patients to ensure compliance with treatment regimens.
Diagnostic testing for OSA should be performed with a comprehensive sleep evaluation and adequate follow-up with a sleep specialist. The clinical evaluation for OSA should include a thorough sleep history and a physical examination that includes the respiratory, cardiovascular, and neurologic systems. Sleep specialists should inquire about snoring, witnessed apneas, nocturnal choking or gasping, restlessness, insomnia, waking unrefreshed, and/or excessive sleepiness. A complete sleep history is essential, since many patients suffer from more than one sleep disorder or present with atypical sleep apnea symptoms.
Sleep specialists should screen for medical conditions associated with increased risk for OSA, such as obesity, atrial fibrillation, hypertension, stroke, and congestive heart failure. The evaluation should serve to establish a differential diagnosis, which can then be used to ensure that the appropriate diagnostic testing is performed to address OSA, as well as other comorbid sleep complaints such as insomnia, REM behavior disorder, parasomnias, restless limbs syndrome and periodic limb movement disorder, nocturnal seizures, and/or pathologic hypersomnia. Follow-up under the supervision of a board-certified sleep medicine physician ensures that study findings and recommendations are relayed appropriately, and that appropriate therapy is made available to the patient.
Many patients suffer from more than one sleep disorder.
Sleep apnea-focused questionnaires lack diagnostic accuracy, making direct measurement of patient sleep patterns necessary to establish a diagnosis of OSA. This may take two forms:
Home sleep testing (HST) is performed in the patient’s residence with a portable monitor that records sleep patterns for subsequent review by a physician specializing in sleep medicine. Some insurance companies require an HST as an initial sleep test. While the home equipment is considered an alternative initial method to diagnose OSA in adults, it cannot diagnose the majority of sleep disorders, and should be followed with an in-lab sleep study when home studies have not adequately confirmed or ruled out OSA.
Polysomnogram (PSG), performed overnight in a sleep study lab with an attendant on hand, is the gold standard for diagnostic testing of OSA. In-lab PSGs can also identify co-existing sleep disorders.
Another benefit of doing in-lab PSG monitoring is that positive airway pressure (PAP) therapy (described below) may be initiated during the test. This allows for more precise treatment and potentially better compliance, by determining appropriate follow-up therapy (e.g., selecting a PAP machine and masks, identifying individualized airflow pressure settings, and addressing challenges encountered in using PAP therapy). It also allows patients to determine if PAP therapy is a desired treatment or whether other options should be pursued early on.
Disadvantages of PSG include the cost associated with evaluating all patients suspected of having OSA with PSG, limitations with insurance coverage, and potentially restricted access to in-laboratory testing in some regions. HST may be less costly and more efficient for some populations.
There are a variety of treatment options available for OSA, including both surgical and nonsurgical options.
Nonsurgical treatment options
The most widely used nonsurgical treatment for moderate and severe OSA in adults is positive airway pressure (PAP) machines, which deliver gently pressurized room air or oxygen through a mask attached to the patient’s nose and/or mouth, ensuring that airways remain open during sleep. Modern technology offers PAP machines that are compact and quiet. New models include modem capability, allowing the provider and patient to continue close monitoring without the need to transport the machine back to the clinic.
The mandibular advancement device (MAD), an oral appliance that increases airway diameter, is another nonsurgical treatment option employed both as primary or as adjunctive treatment for OSA. MAD is beneficial in that it is compact and portable, making it easy to travel with. This therapy is more discreet and allows individuals to be more intimate with their bed partner (no machine in the way). No electricity is needed, which can be ideal for camping, cabins, and travel. Consequences of MAD that need to be monitored include TMJ (temporomandibular joint disorders) arthritis or arthralgia (pain); bite changes or teeth shifting; and hypersalivation, mouth dryness, and/or tooth discomfort.
If clinically indicated, patients should be encouraged to lose weight. Positional therapy (promoting lateral sleep and/or elevating the head of the bed) should also be considered for certain populations.
Untreated OSA results in significant cardiovascular and cerebrovascular complications.