EFFECT OF OXYGEN ON THE REGIONAL DISTRIBUTION OF VENTILATION AND PERFUSION IN THE LUNG

Abstract

Xenon¹³³ was used to measure distribution of ventilation and perfusion in the upper, middle, and lower lung zones of 12 upright healthy male subjects, at rest and during exercise, while breathing room air and after breathing 100% oxygen for 20 minutes. During the breathing of both air and 100% oxygen, ventilation and perfusion increased from the apex to the base of the lung, the differences between upper and lower zones becoming less pronounced during exercise. Oxygen breathing did not appear to affect distribution of regional ventilation or perfusion in normal upright man, either at rest or during exercise. This negative result is of importance in relation to the possible role in intact man of homeostatic mechanisms of adjusting perfusion and ventilation, which are sensitive to oxygen tension.