O volume expiratório forçado no primeiro segundo não é suficiente para avaliar resposta broncodilatadora em doença pulmonar obstrutiva crônica

Abstract

Objective: To assess the frequency of variation in forced expiratory volume in one second after bronchodilator use in a sample of patients with chronic obstructive pulmonary disease, correlating such variation with clinical and demographic variables and evaluating the frequency of response presented in forced vital capacity, slow vital capacity, inspiratory capacity, residual volume, airway resistance and specific airway conductance. Methods: A total of 64 patients with chronic obstructive pulmonary disease were submitted to whole body plethysmography, and reversibility of bronchoconstriction after the administration 400 µg of fenoterol was quantified. Results: A response in forced expiratory volume in one second was observed in 31% of the patients. Excluding patients presenting a response in forced expiratory volume in one second, 5% presented responses in 5 of the other 6 parameters, 10% presented responses in 4 parameters, 17.5% in 3 parameters, 27.5% in 2 parameters, and 25% in only 1 parameter. Conclusion: When included in the evaluation of bronchodilator response together with forced expiratory volume in one second, static lung volumes, airway resistance and airway conductance allowed a broader evaluation of those patients presenting a functional pharmacodynamic response. These results are in accordance with the observation that bronchodilator use provides clinical improvement and relief of dyspnea to many patients with chronic obstructive pulmonary disease, even to those in whom such treatment leads to no improvement in forced expiratory volume in one second. Original Article

Volume expiratório forçado no primeiro segundo e resposta a broncodilatador em doença pulmonar obstrutiva crônica: um ritual inútil?

“…the FEV 1 /FVC ratio does not change, demonstrating reduced air trapping caused by the concomitant increase in FVC. In the Tavares et al study, (13) the significantly higher rate of response in SVC and FVC by patients in the group that presented significantly elevated FEV1 is evidence of such volume recruitment.…”

“…Therefore, increases in IC after bronchodilator use are associated with better exercise tolerance. (9)(10)(11)(12) The study conducted by Tavares et al (13) and presented in this issue of the journal shows that 90% of patients with COPD responded in one or more functional parameters after bronchodilator use, although FEV 1 detected only 31% of the responses. Forced vital capacity (FVC) was the parameter that varied most frequently, followed by residual volume, specific airway conductance and SVC.…”