Role of Methacholine PC20 in FEF25-75% for the Diagnosis of Bronchial Asthma

Kyeong Min Son, Seung Hun Jang, Hye Ryun Kang, Boram Han, Joo Hee Kim, Hyun Sung Kim, Sung Hoon Park, Yong Il Hwang, Dong Gyu Kim, Ki Suck Jung
2009 Tuberculosis and Respiratory Diseases  
The methacholine bronchial provocation test is a useful tool for evaluating asthma in patients with normal or near normal baseline lung function. However, the sensitivity of this test is 82∼92% at most. The purpose of this study is to evaluate the clinical usefulness of FEF 25-75% in identification of airway hyperresponsiveness in patients with suspected asthmatic symptoms. Methods: One hundred twenty-five patients who experienced cough and wheezing within one week prior to their visiting the
more » ... heir visiting the clinic were enrolled. Results: Sixty-four subjects showed no significant reduction of FEV1 or FEF25-75% on the methacholine bronchial provocation test (Group I). In 24 patients, FEF25-75% fell more than 20% from baseline without a 20% fall of FEV1 during methacholine challenge (Group II). All patients who had more than 20% fall of FEV 1 (n=37) also showed more than 20% of reduction in FEF25-75% (Group III). Baseline FEV1/FVC (%) and FEF25-75% (L) were higher in group II than group III (81.51±1.56% vs. 75.02±1.60%, p<0.001, 3.25±0.21 L vs. 2.45±0.21 L, p=0.013, respectively). Group II had greater reductions of both FEV 1 and FEF 25-75% than group I at 25 mg/mL of methacholine (p<0.001). The provocative concentration of methacholine causing a 20% fall in FEF25-75% in group II was about three-fold higher than that in group III. Conclusion: A 20% fall of FEF 25-75% by methacholine provocation can be more sensitive indicator for detecting a milder form of airway hyperresponsiveness than FEV1 criteria.
doi:10.4046/trd.2009.67.4.311 fatcat:so6hrgqzcbeajd42czznmbmnmm