[Aerodynamic studies of the upper respiratory tract]

The usefulness of flow-volume curves for the assessment of upper airway function is emphasized. The different behaviour of intra- and extra-thoracic airways, submitted to different transmural pressures, results in the reduction of maximum expiratory flows in cases of variable intrathoracic airways stenosis, whereas in the presence of an extrathoracic stenosis, the inspiratory maximum flows are mainly affected. Sleep apnea syndrome and "asthma-like" syndromes with a glottic origin are further examples of the potentials of flow-volume loops in the assessment of upper airway function.