Bronchial responsiveness in patients with restrictive spirometry.

Background: Improvement in PFT after bronchodilators is characteristic of obstructive airway diseases such as COPD. However, improvement in patients with restrictive pattern is occasionally seen. We aim to determine the clinical significance of a bronchodilator responsive restrictive defect.
Methods: Patients with restrictive spirometry and a bronchodilator study were identified at the University of Oklahoma and Oklahoma City VAMC between September 2003 and December 2009. Restriction was defined as a decreased FVC and FEV1, with normal FEV1/FVC. Responsiveness to bronchodilators was defined as an improvement in FEV1 and/or FVC of at least 12% and 200 mL. Patients with lung volume measurements had their clinical and radiographic records reviewed.
Results: Twenty-one patients were included in the study. Most were current or ex-smokers, with most being on bronchodilators. The average FVC and FEV1 were 65 ± 11% and 62 ± 10% of the predicted, respectively. Most patients (66%) had a normal TLC, averaging 90 ± 16% of the predicted. RV, RV/TLC, and the TLC-VA values strongly suggested an obstructive defect.
Conclusions: Reversible restrictive pattern on spirometry appears to be a variant of obstructive lung disease in which early airway closure results in air trapping and low FVC. In symptomatic patients, a therapeutic trial of bronchodilators may be beneficial.