Upper airway dysfunction detected by respiratory flow oscillations.

In 3 patients with chronic respiratory symptoms, we identified rapid flow oscillations on flow-time and flow-volume recordings, corresponding to fluttering of lax but otherwise normal-appearing upper airway structures at cinefluoroscopy and fiberoptic endoscopy. This entity of upper airway dysfunction was responsible for, or at least contributed to, the respiratory symptoms as evidenced by dramatic relief of dyspnea following tracheostomy in one patient, and significant improvement of flow rates following helium breathing in the other 2 patients. We suggest that identification of flow oscillations on flow recordings, in particular flow-volume loops, should lead to investigation of the upper airway. When fluttering is the only abnormality observed, it should not be disregarded, but rather considered as possibly contributing to airflow limitation.

Involvement of upper-airway muscles in extrapyramidal disorders. A cause of airflow limitation.

To identify the site and cause of airflow limitation in patients with parkinsonism, we tested pulmonary function in 27 patients with extrapyramidal disorders. In 24 patients, an abnormal flow-volume loop contour, showing either regular (18 patients) or irregular (6 patients) flow oscillations, was found. On direct fiberoptic visualization of the upper airway, these oscillations corresponded to either rhythmic (4 to 8 Hz) or irregular involuntary movements of glottic and supraglottic structures. Ten patients had physiologic evidence of upper-airway obstruction, which was symptomatic in four. We conclude that the upper-airway musculature is frequently involved in extrapyramidal disorders. This causes upper-airway dysfunction that can be severe enough to limit airflow.