[Value of the flow-volume curve in the evaluation of non-obstructive dyspnea complaints]

The flow-volume curves of 246 patients with dyspnoea on exertion were analysed. In the presence of normal lung volumes and capacities and normal airway resistance, 52% of the patients were found already to have pathologically changed forced expiration figures. In patients with non-bronchogenic disorders, a predominately inspiratory reduction in flow was detected, in particular a reduction in maximum flow. Characteristic findings can be established already in the initial stage of ventilation disorders. Patients with diffuse pulmonary diseases are characterised by a virtually normal PEF, a steep decline in phase II of forced expiration, and a restriction in inspiration. Goitre-associated stenoses with a functional effect are characterised by a reduced expiratory peak flow, homogeneous expiration and reduced inspiratory flow. In patients with bronchial diseases, a functional overdistension can be detected even in the symptom-free stage with the aid of the quotient ITGV % MEF50% VC. In our opinion, the flow-volume curve should therefore be considered an indispensable investigation within the framework of pulmonary function diagnostic evaluation.