Evaluation of the Severity in Patients with Bronchial Asthma Using FEF25-75%

Jung, Sun Yoon; Lee, Eun Sil; Lee, Young Hwan; Moon, Han Ku

Abstract

PURPOSE
Spirometry, because of its simplicity and reproducibility, has been used to evaluate pulmonary function in childhood asthma. We investigated whether FEF25-75% is the most sensitive parameter among other spirometric parameters in the diagnosis of pulmonary function and airway obstruction.
METHODS
This study included 32 children with asthma. We recorded values of spirometry(FVC, FEV1, PEFR, and FEF25-75%) before and after symptomatic improvement and compared them. The values were recorded as a percent of the predicted normal value.
RESULTS
The FEV1 value before and after symptomatic improvement was 71.7+/-15.6% and 83.8+/-12.8%, respectively; PEFR was 75.4+/-18.3% and 85.0+/-16.0%; and FEF25-75% was 60.8+/-17.9% and 81.5+/-16.3%. According to symptomatic improvement, FEF25-75% improved more than the other spirometric parameters. Of the 40 cases of spitometric measurement before symptomatic improvement, abnormal FEV1, PEFR, FEF25-75% values were observed in 25, 17 and 28 cases, respectively. There was statistically significant difference between FEF25-75% and PEFR(P=0.005), but not between FEF25-75% and FEV1(P=0.091). After symptomatic improvement, abnormal FEV1, PEFR, and FEF25-75% values were observed in 14, 12 and 9 cases, respectively. There was statistically significant difference between FEF25-75% and FEV1(P=0.044) but not between FEF25-75% and PEFR (P=0.097). The cases of normalized values with symptomatic improvement, 11 in FEV1, 7 in PEFR and 19 in FEF25-75%.
CONCLUSION
FEF25-75% showed the most improvement rate before and after symptomatic improvement. FEF25-75% was helpful in the assessment of treatment effectiveness and reversible bronchial responsiveness. However, this study did not suggest that FEF25-75% is the most sensitive measurement of airway obstruction.