An obese 50-year-old woman complains of insomnia, daytime sleepiness, and fatigue. During a sleep study she is found to have recurrent episodes of arterial desaturation —about 30 events per hour—with evidence of obstructive apnea. Which of the following is the treatment of choice for this patient?A) Nasal continuous positive airway pressure
This patient with multiple episodes of desaturation has obstructive sleep apnea (OSA). In OSA, upper airway muscle tone decreases as the patient achieves deep stages (stages 3 and 4) of sleep; the soft palate falls against the base of the tongue, leading to obstruction of air flow and snoring. Microawakening occurs, leading to improvement in muscle tone but at the cost of shallow unrefreshing sleep. This leads to daytime somnolence (due to sleep deprivation), hypertension (due to hyperadrenergic state), and even cor pulmonale and chronic hypercarbia (due to hypoxia). At present fewer than five apneic episodes per hour are considered normal. The severity of sleep apnea is graded using the apnea/hypopnea index. Mild sleep apnea is 5 to 15 events per hour; moderate sleep apnea is 16 to 30; severe apnea is greater than 30 events per hour Continuous positive airway pressure is the recommended therapy. Weight loss is often helpful and should be recommended as well. However, weight loss alone will take significant time and may not be sufficient. Uvulopalatopharyngoplasty, when applied to unselected patients, is effective in less than 50%. A trial of CPAP is indicated before surgical therapy. Tracheostomy is a treatment of last resort in severe and refractory sleep apnea; it does provide immediate relief of the upper airway obstruction. Oxygen alone is less effective than CPAP.