Journal of Applied Physiology, Vol 57, Issue 3 772-776, Copyright © 1984 by American Physiological Society
Change in extra-alveolar perimicrovascular pressure with lung inflation
A. C. Jasper and H. S. Goldberg
In eight isolated dog lobes, we examined the change in extra-alveolar
perimicrovascular hydrostatic pressure (Pis) due to lung inflation. The
vasculature was filled with autologous plasma. Pulmonary arterial and
venous lines were connected to a common plasma reservoir. Perimicrovascular
volume change (delta Vis), compliance (Cis), and the microvascular
filtration coefficient (Kf) were derived from the change in lobe mass over
time following a step increase in vascular pressure (Piv). Initially,
transpulmonary pressure (PL) was 5 cmH2O and Piv = 0 cmH2O. At constant
Piv, two sequential 5-cmH2O increases in PL increased Vis; division of
delta Vis by Cis yielded the change in Pis attributable to lung inflation.
Cis was 0.035 +/- 0.018 g X cmH2O-1 X g dry mass-1 (mean +/- SD) at PL = 15
cmH2O. Kf was 0.019 +/- 0.023 g X min-1 X cmH2O-1 X g dry mass-1. With
inflation from PL = 5 to PL = 10 cmH2O, Pis = -2.15 +/- 1.76 cmH2O; from PL
= 10 to PL = 15 cmH2O, Pis = -2.25 +/- 1.50 cmH2O. This perimicrovascular
pressure change is very close to the perihilar interstitial pressure change
reported by others. Such near equality suggests that the stress of lung
inflation is very uniformly applied to the interstitial continuum.
