1. Continuous Positive Airway Pressure for Sleep Apnea
CLINICAL THERAPEUTICS, Continuous Positive Airway Pressure for Obstructive Sleep Apnea, R.C. Basner, Extract | Full Text | PDF | PPT Slide Set

A 48-year-old man reports that his wife tells him he snores loudly and that he has been falling asleep whenever sedentary during the day. His body-mass index is 32, and he has hypertension. How should he be evaluated and treated?

Clinical Pearls

Obstructive Sleep Apnea and Obstructive Sleep Apnea-Hypopnea Syndrome
Obstructive sleep apnea, defined as the presence of at least five obstructive events (apnea and hypoapneas) per hour during sleep, is found in 9 to 26% of middle-aged people who lack specific risk factors for the disorder. The obstructive sleep apnea-hypopnea syndrome, defined as the presence of at least five obstructive events per hour with associated daytime sleepiness, is present in 2 to 4% of the same population. The prevalence in men is almost three times that in premenopausal women and twice that in postmenopausal women. Other factors associated with an increased prevalence are obesity, older age, and systemic hypertension.

Treatments for Obstructive Sleep Apnea
Continuous Positive Airway Pressure (CPAP) is considered first-line therapy for severe obstructive sleep apnea and for obstructive sleep apnea with concomitant cardiovascular disorders. Weight-loss counseling should be considered an important part of treatment. Other therapies include oral appliances, sleep positioning, and uvulopalatopharyngoplasty. Tracheostomy is reserved for patients with severe obstructive sleep apnea and cardiorespiratory compromise in whom CPAP is neither tolerated nor effective.

Figure 1. Polysomnogram of a Patient with Severe Obstructive Sleep Apnea, Using CPAP.

Health Risks of Severe Obstructive Sleep Apnea
Excessive daytime sleepiness and impairments in the ability to sustain attention to tasks, in working memory, and in the quality of life are consistently demonstrated in obstructive sleep apnea. Sleep apnea is also associated with an increased risk of motor vehicle accidents. An increased prevalence of cardiovascular and cerebrovascular disease, as well as insulin resistance, are associated with obstructive sleep apnea. Untreated male patients with severe obstructive apnea have significantly greater risks of fatal and nonfatal cardiovascular events than healthy controls.

Morning Report Questions

Q: What physiological changes cause stimulation and awakening in a sleeping patient with obstructive sleep apnea?

A: Progressive upper-airway closure during the transition to sleep is accompanied by complete obstruction of airflow (apnea) or partial obstruction (hypopnea). Hypercapnia and acidosis resulting from hypoventilation stimulate arousal centers in the central nervous system, leading to increased respiratory and pharyngeal-muscle activity. These changes in neurologic function, further stimulated by increasing ventilatory effort itself, ultimately overcome the obstruction, and ventilation resumes. The patient then returns to sleep, the pharyngeal musculature relaxes, and the cycle repeats itself.

Q: What are commonly reported side effects of continuous positive airway pressure (CPAP) therapy?

A: Commonly reported adverse effects of CPAP include irritation, pain, rash, or skin breakdown at mask contact points, particularly the bridge of the nose, or within the nares when nasal pillows are used. Dryness or irritation of the nasal and pharyngeal membranes, nasal congestion and rhinorrhea, and eye irritation from air leakage are also common. Claustrophobia, gastric and bowel distention, and recurrent ear and sinus infections are less common effects. Proper adjustment and fitting of the interface, humidification, and careful adjustment of pressure levels are usually sufficient to allow continued use of CPAP.

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