The spectrum of clinical disorders related to sleep-induced upper airway obstruction is illustrated in

Fig. 67-5. Unfortunately, we lack good prospective studies characterizing the long-term clinical consequences of simple heavy snoring or mild sleep-disordered breathing in untreated individuals. Accordingly, we do not know exactly what indices of apnea frequency, oxyhemoglobin desaturation, and sleep fragmentation require treatment. Most symptomatic patients with more than 20 apneas and hypopneas per hour of sleep or severe oxyhemoglobin desaturation should be treated. However, symptomatic patients with fewer sleep-disordered breathing events may also benefit from treatment.

These patients may have debilitating sleepiness because of frequent arousals from sleep provoked by breathing efforts against a partially collapsed pharynx but few actual apneas or hypopneas. This is the so-called upper airways resistance syndrome (

see Fig. 67-5). On the other hand, levels of sleep-disordered breathing formerly considered pathologic (>5 apneas/hour of sleep) have been reported in healthy, asymptomatic persons, especially with aging. Therefore the decision to treat must be based on an overall assessment of the severity of sleepiness and related symptoms, cardiac sequelae, and the severity of sleep-disordered breathing and sleep fragmentation documented on polysomnography.