Inspiratory capacity and forced expiratory volume in the first second in exacerbation of chronic obstructive pulmonary disease.

OBJECT: Periodic exacerbations of symptoms are the major cause of morbidity, mortality and health care costs in patients with chronic obstructive pulmonary disease (COPD). Dyspnea is the major factor affecting the comfort of patients in the exacerbation of COPD. In this study, we aimed to compare the value of forced expiratory volume in the first second (FEV(1)) and inspiratory capacity (IC) measured before and after treatment in exacerbations and in the improvement in dyspnea.

METHODS: Eighty-seven patients (male/female, 80/7; mean age, 63 +/- 7) with COPD exacerbation were included in this study. All subjects underwent spirometric tests on the first day and at the end of treatment. The subjects were asked to quantify the sensation of dyspnea that was described to them as a nonspecific discomfort associated with the act of breathing. The patients quantified dyspnea by pointing to a score on a large Borg scale from 0 to 10 arbitrary units. In the beginning and at the end of treatment, forced vital capacity (FVC), FEV(1), forced expiratory flow rate between 25% and 75% of FVC (FEF25-75), peak expiratory flow rate (PEF), IC and Borg score (BS) values were compared.

RESULTS: After treatment of COPD exacerbations, FEV(1), FEF25-75, PEF and IC significantly increased, and the BS significantly decreased compared to the initial values. The increase in IC was more significantly correlated with the improvement in BS compared with FEV(1). Admission and discharge day BS was negatively correlated with FEV(1), FEF25-75 and IC.

CONCLUSION: We have shown a more dramatic improvement in IC compared with FEV(1) in patients treated as a result of acute exacerbation of COPD. These data suggest that IC may be more useful than FEV(1) during acute exacerbation of COPD. Moreover, IC better reflects the severity of dyspnea in these patients.