[Evaluation of ventilatory function of the small airways].

The results of functional tests and the values of flow-volume and spirometric parameters were reevaluated in 1174 randomly selected patients with no evidence of heart disease. There were 533 patients with normal ventilation and 327 patients with no restrictive disorders. In the latter group 11% of the patients had normal FEV1 and lowered FEF50 and FEF75 values. In those patients obstructive changes would not have been found if expiratory flow rates had not been taken into account as one of the criteria for evaluating airway obstruction. In further 13% of the patients a mild airway obstruction would have been found had only FEV1 been evaluated without taking account of expiratory flow rates. It is concluded that expiratory flow rates along with anamnestic data and clinical status are important indicators of obstructive changes of ventilation, especially as they serve to identify functional disorders while these are still reversible and therapy can be useful.