Question

A 50 per cent fall in the ventilation/perfusion ratio in one lung would 

A. Lower systemic arterial oxygen content. 

B. Have effects similar to those of a direct right to left atrial shunt. 

C. Increase the physiological dead space. 

D. Lower systemic arterial carbon dioxide content. 

E. Be compensated (with respect to oxygen uptake) by a high ratio in the other lung.

Answer 1

A. True It constitutes a physiological shunt. 

B. True This would be an anatomical shunt. 

C. False Physiological dead space is relatively over ventilated. 

D. False It would tend to raise it. 

E. False Increased ventilation cannot increase oxygen saturation; compensation for carbon dioxide retention can occur.