How is obstructive sleep apnea diagnosed?
The first clinical indicator of obstructive sleep apnea, loud snoring, is frequently reported by the patient’s sleeping part-ner. Definitive diagnosis is obtained by sleep studies, which look for apnea and hypopnea. Apnea is the total cessation of gas flow through the airway, despite attempts to breathe. Hypopnea is reduction of gas flow through the airway while breathing. Diagnostic criteria generally include five or more episodes of apnea lasting 10 seconds or more, associated with a 4% decrease in oxygen saturation by pulse oximetry (SpO2). Other criteria include 15 or more episodes of hypop-nea attaining at least a 50% decrease in flow lasting 10 sec-onds or longer, and associated with a 4% decrease in SpO2.
Although most patients with obstructive sleep apnea are morbidly obese, many lean patients suffer from this problem. It tends to occur in middle-aged and elder adults. Obstructive sleep apnea may be exacerbated by sedatives, hypnotics, alcohol, or muscle relaxants. Young patients with craniofacial abnormalities sometimes manifest obstructive sleep apnea, also.