Evaluation and diagnosis of sleep-disordered breathing

Sleep-disordered breathing is defined as abnormal breathing patterns that disrupt sleep [1]. There are several types of sleep-disordered breathing patterns including hypopneas, apneas, and respiratory effortrelated arousals. Apnea is defined as a cessation of airflow for 10 or more seconds [2,3]. Partial obstructive events called hypopneas have historically been defined differently by different sleep disorders centers and sleep specialists. Because of a lack of uniformity in definitions, and partly because of difficulties in diagnosing and treating Medicare patients, the American Academy of Sleep Medicine has recently redefined hypopneas as abnormal respiratory events lasting at least 10 seconds, with at least a 30% reduction in airflow or thoracoabdominal movement with at least a 4% oxygen desaturation. The associated arousals historically associated with hypopneas have now been eliminated from the definition. This new definition is based on epidemiological data relating to sleep-related breathing disorders and cardiac disease [2]. The data relating to obstructive sleep apnea syndrome, and to both cardiovascular and cerebrovascular disease, is growing. Another abnormal breathing pattern is termed upper airway resistance syndrome. It is diagnosed in patients who present with daytime sleepiness caused by a narrowing or increased resistance of their upper airway when sleeping without diagnosable apneas or hypopneas. These patients generally have brief electroencephalography (EEG) arousals that may fragment sleep and cause the complaint of daytime sleepiness [4]. Common characteristics of patients who present for an apnea consultation include obesity, sleepiness, snoring, snorting, gasping, choking, and witnessed apneas at night. Hypertension, nocturia, and morning headaches may also be experienced. Patterns of apnea