[The diagnosis of upper airway obstruction by flow-volume loops (author's transl)].

The recognition of upper airway obstruction (UAO) is occurring more frequently, especially after prolonged intubation for artificial ventilation. The diagnosis of UAO may be inferred by the clinical signs or spirometry; however, these methods are not reliable. We present 4 cases of UAO to illustrate the role of the flow-volume loop in securing the correct diagnosis. These cases demonstrate the utility of the flow-volume loop as a simple technique in confirming the presence of UAO.