Question: Emphysema is a disease process that can be caused by cigarette smoking. Not only are the lungs more inflated at rest due to loss of elasticity (elastic recoil), but the alveoli are also reduced in numbers as fewer, large diameter alveoli replace more numerous, smaller diameter alveoli. As a consequence, patients with emphysema are often given supplemental oxygen to assist with their changed breathing pattern. What is the main objective in administering supplemental oxygen?
Hint: Effects of emphysema on pulmonary gas exchange.
Emphysema affects both the ventilation of alveoli and the surface area of the alveoli available for pulmonary gas exchange. Consequently, both the PO2 in the alveoli and the total surface area available for oxygen diffusion are reduced.
A) Increase the PO2 of pulmonary blood above 100 mm Hg so that more oxygen can be carried as dissolved oxygen in the plasma.
B) Increase the PO2 of pulmonary blood above 100 mm Hg so that more oxygen can be carried by hemoglobin.
C) Increase the PO2 in the alveoli to decrease the alveolar PCO2.
D) Increase the PO2 in the alveoli to increase the diffusion of oxygen across the respiratory membrane.
