Anatomic distribution of pulmonary vascular compliance

Presson, Robert G., Jr., Said H. Audi, Christopher C. Hanger, Gerald M. Zenk, Richard A. Sidner, John H. Linehan, Wiltz W. Wagner, Jr., and Christopher A. Dawson. Anatomic distribution of pulmonary vascular compliance. J. Appl. Physiol. 84(1): 303–310, 1998.—Previously, the pressure changes after arterial and venous occlusion have been used to characterize the longitudinal distribution of pulmonary vascular resistance with respect to vascular compliance using compartmental models. However, the compartments have not been defined anatomically. Using video microscopy of the subpleural microcirculation, we have measured the flow changes in ∼40-μm arterioles and venules after venous, arterial, and double occlusion maneuvers. The quasi-steady flows through these vessels after venous occlusion permitted an estimation of the compliance in three anatomic segments: arteries >40 μm, veins >40 μm, and vessels <40 μm in diameter. We found that ∼65% of the total pulmonary vascular compliance was in vessels <40 μm, pres...