Characterization of bronchodilator response by spirometry and whole body pletysmography
Authors: Raquel Barros, Carina Neves, Diana Fernandes, Paula Pinto, Cristina Bárbara
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Background: After the detection of airway obstruction it is common to administrate a bronchodilator and then evaluate the response to the therapeutic. Most societies consider that a positive response to the bronchodilator exists when FEV1 and/or FVC increased 12% and 200mL.
Objeticve: To characterize the response to the bronchodilator according to criteria found in the literature.
Method: Cross-sectional study. The sample included 52 subjects who performed lung function tests, and in whom an airway obstruction was detected with subsequent administration of bronchodilator. The sample was divided according to criteria of bronchodilator response and pulmonary hyperinflation proposed by ATS/ERS (Miller et al., 2005a; Miller et al., 2005b).
Results: For the totality of the sample, the criterion which was able to detect the largest number of subjects with positive response to the bronchodilator was the increase of FEF25-75% ≥10% (63,5%). For the group with the presence of ATS/ERS criteria it was the increase of IC≥10% (76,9%) and for the group without this criteria it was the increase of FEF25-75% ≥10% (61,5%). For the group with pulmonary hyperinflation the best criteria were the increase of FEF25-75% ≥10% (66,7%) and the reduction of RV≥10% (66,7%), and for those without pulmonary hyperinflation it was the increase of FEF25-75% ≥10% (62,2%).
Conclusion: The criterion which was able to detect the largest number of positive responses to bronchodilator was the increase of FEF25-75% ≥10%. However due to the existence of other criteria with good discriminative capacities we suggest a combination of several criteria for the correct characterization of airway reversibility.