All the following are true regarding COPD EXCEPT

Ans. c (Decreased residual volume/total lung capacity ratio) (Ref. H-16,h/pg. no. 1542-47 ; Table 242-1)COPD# Pulmonary function testing shows airflow obstruction with a reduction in FEV/ and FEV/FVC.# With worsening disease severity, lung volumes may increase, resulting in an increase in total lung capacity, functional residual capacity, and residual volume.# In emphysema, the diffusing capacity may be reduced, reflecting the parenchymal destruction.# Degree of airflow obstruction is imp prognostic factor in COPD and is the basis for GOLD disease classification.# Computed tomography (HRCT) scan is the current definitive test for establishing the presence or absence of emphysema.Gold criteria for copd severityGold StageSeveritySymptomsSpirometry0At riskChronic cough, sputum productionNormalIMildWith or without chronic cough or sputum production predictedFEV1/FVC < 0.7 and FEV1 80%IIAModerateWith or without chronic cough or sputum production < 80% predictedFEV1/FVC < 0.7 and 50% = FEV1IIISevereWith or without chronic cough or sputum production< 50% predictedFEV1/FVC < 0.7 and 30%=FEV1IVVery severeWith or without chronic cough or sputum production predicted or FEV1 < 50% predicted with respiratory failure or signs of RHFFEV1/FVC < 0.7 and FEV1 < 30%Clinical Correlation: Changes in lung Compliance| ComplianceEmphysema# Less elastic recoil of lungs, so FRC |# Chest wall expands and becomes barrel-shaped# Also, | RV, | TLC,|FVC,| Raw|ComplianceFibrosis, respiratory distress syndrome# Tendency of lungs to collapse, so FRC |# Also, ||TLC, |RV, ||FVC