<prompt> True about chronic obstructive pulmonary disease COPDFEVI 30 of predicted valueFEV1FVC0.7total lung capacity increasedAll  <response>: In COPD,airflow obstruction is demonstrated by spirometry in which the post- bronchodilator FEV1FVC is less than 70.The severity of COPD may be defined in relation to the post - bronchodilator FEV1 which is 30 predicted in very severe type.Measurement of lung volumes provides an assessment of hyperinflation.COPD is characterised by increase in residual volume,residual volumetotal lung capacity ratio,and progressive hyperinflationincreased total lung capacity late in the disease. source : Harrison 20 th edition. 