title: The detection of sleep apnea in the awake patient. The 'saw-tooth' sign.
abstract: We studied 21 subjects, 13 of whom had the sleep apnea hypersomnolence syndrome associated with upper airway obstruction during sleep (SAHS-UAO) to determine if "saw-toothing" on the flow-volume loop was significantly associated with the phenomenon of airway occlusion during sleep. A "saw-tooth" pattern was present on the flow-volume loop in 11 of 13 subjects with SAHS-UAO. The presence of saw-toothing correlated with fluttering of tissue that was visualized in the upper airway via the fiberoptic bronchoscope. The specificity of the saw-tooth pattern for SAHS-UAO was 100%. Generalized obesity may indirectly influence the presence of saw-toothing due to deposition of what appeared to be adipose tissue in the pharyngeal walls. Although the number of subjects in this study is small, saw-toothing on the flow-volume loop appears to be an important aid in the diagnosis of SAHS-UAO.
mesh_terms: D000293:Adolescent; D000328:Adult; D000402:Airway Obstruction / Q000150:complications; D001835:Body Weight; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008722:Methods; D008875:Middle Aged; D012891:Sleep Apnea Syndromes / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D013577:Syndrome; D014797:Vital Capacity; D014851:Wakefulness