Distribution of Pulmonary Blood Flow during the Valsalva and Müller Maneuvers

Abstract

During the Valsalva and Müller maneuvers, the effect of different levels of superatmospheric and subatmospheric alveolar pressures on the distribution of pulmonary perfusion was studied with the ¹³³Xe method in 14 healthy subjects in the sitting position. Significantly increased unevenness was found to attend alveolar pressures of +20 and +40 mm Hg, whereas negative alveolar pressures (-5 to -40 mm Hg) resulted in significantly decreased unevenness of perfusion. The results are interpreted as due mainly to alterations in venous return.

Key Words:

• Alveolar pressure
• mouth pressure
• Müller maneuver
• regional lung function
• Valsalva maneuver
• venous return
• Xenon