Which of the following is involved in hypoxia in a smoker with noticeable increase in anteroposterior chest width if oxygen therapy is effective? (AIIMS May 2013)
|A||Anaemia caused by blood loss|
|D||Right-to-left cardiac shunts|
a. Chronic pulmonary emphysema is characterized by distention of small air spaces distal to the respiratory bronchioles and destruction of alveolar septa. Long-term cigarette smoking is the usual cause.
b. The marked loss of lung parenchyma associated with emphysema leads to a decrease in the diffusion capacity of the lungs that reduces their ability to oxygenate blood and remove carbon dioxide, contributing to the "barrel chest" appearance of these patients.