Diagnostic performance of lung volumes in assessment of reversibility in chronic obstructive pulmonary disease

Abstract Background Reversibility measured by spirometry in chronic obstructive pulmonary disease (COPD) is defined as an increase forced expiratory volume first second (FEV1) that both more than 12% and 200 mL above the pre-bronchodilator value response to inhaled bronchodilators. FEV1 only may not fully reverberate changes caused reduction air trapping or hyperinflation. To date, studies examined effect of bronchodilators (BD) on residual (RV) total lung capacity (TLC) are limited. This study was carried out assess differences between flow responses after bronchodilator reversibility testing patients with different COPD GOLD stages (GOLD stage I IV). Spirometry whole body plethysmography were done before 15 min inhalation 400 μg salbutamol. Results Majority (53.3%) cases responders, 18.7% 20% 8% non responders. Significant Δ FEV1% found 15% while 55% showed a significant FVC ( P = < 0.001). Mean difference (L) post BD significantly increased advancing 0.03). A cutoff point > for RV% had 70% sensitivity 60% specificity TLC% 90% 45% prediction clinically based FEV1. 18% 78% 29% 14% 50% FVC. Conclusion ΔFEV1 underestimates true stage. Measurement volumes addition standard spirometric indices recommended when determining patients.