Patients with Chronic Paralytic/Restrictive Ventilatory Dysfunction (3)
The diagnosis of OSAS is considered in the presence of characteristic symptoms including hypersomnolence, fatigue, and morning headaches, as well as in the presence of unexplained cor pulmonale. The usual presence of heavy snoring and observed periods of apnea often seen in patients with classic OSAS may not be present in patients using BVs. In either case, the condition is characterized by ten or more apneas plus hypopneas per hour during sleep. An episode of apnea has been defined as a cessation of airflow lasting at least 10 s. An episode of hypopnea has been defined as a decrease in tidal volume to one-third or less of the baseline value of the immediately preceding breaths that persists for greater than 10 s. Virtually every apnea and hypopnea is associated with a 4 percent or greater drop in oxyhemoglobin saturation (SaOa). Obstructive sleep apnea syndrome occurs in at least 3 percent of the population. buy cipro
Thirty or more apneas and hypopneas per hour and dSa02 to 60 percent or lower is not uncommon in severely symptomatic patients with OSAS.
Both apneas and hypopneas may be centrally derived or may result from upper airway obstruction. Obstruction occurs because of the tendency of the upper airway to collapse when a pressure gradient is created across it by the action of the inspiratory muscles.