In the mild asthmatic attacks, partially treated asthma, early stages of bronchial asthma and in between the
asthmatic attacks, sometimes we find patients with a history suggestive of asthma and normal PFT (FEV1
+FEV1/FVC > 80% of the predicted value).
This study investigated the value of FEF 25-75 measurement as a predictor of the presence of a reversible
airway obstruction (RAO) in adult patients with clinical features of asthma and normal pulmonary function test.
64 patients with clinical features suggestive of asthma and normal pulmonary function test were included in the
study. These patients were subdivided into three groups, group 1 were those with normal pulmonary function
test and FEF 25-75>70%, group 2 were those with normal pulmonary function test and FEF 25-75< 70%>55%
and group 3 are those with normal pulmonary function test and FEF 25-75<55%.each of the study group was
compared with 35 sex and age matched healthy volunteers. Forced expiratory volume in 1 second (FEV1),
forced vital capacity (FVC), FEV1/FVC and FEF25 – 75 were measured before and 10-20 minutes after
salbutamol administration (by nebulizer).
Of the 64 subjects, the percentage of subjects with RAO (FEV1 increase after bronchodilator >12 %) was lower
(11%) in the group 1 (27 subjects) and higher (44%) in the subjects of the group 2 (23 subjects) and highest
(52%) in the subject of group 3 (14 subjects ). FEF25-75 percent predicted is a good predictor of the presence of
reversible airways obstruction in asthmatic patient with normal PFT.