Journal of Applied Physiology, Vol 69, Issue 4 1460-1466, Copyright © 1990 by American Physiological Society
Effects of ligation and embolization on Kf and multiple tracer measurements in dog lungs
J. D. Bradley, R. E. Parker, T. R. Harris and K. A. Overholser
Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37235.
In isolated blood-perfused dog lungs, the capillary filtration coefficient
(Kf) and the permeability-surface area product of urea (PS) were measured
to determine their responses to two different methods of altering
filtration area: lobe ligation (LL, n = 5) and glass bead embolization
(GBE, n = 4) during constant perfusion rates (700 +/- 45 ml/min). When two
of three lobes were ligated, Kf decreased (1.36 +/- 0.13 to 0.58 +/- 0.23
g.min-1.cmH2O-1; P less than 0.05), but PS did not change (2.02 +/- 0.4 to
1.71 +/- 0.3 ml/s). Kf per gram of perfused blood-free dry lung weight was
unchanged by LL (0.051 +/- 0.17 to 0.052 +/- 0.18 g.min-1.cmH2O-1),
indicating that surface area per gram measured by Kf remained the same.
However, PS per gram dry lung doubled (0.07 +/- 0.016 to 0.146 +/- 0.06
ml/s; P less than 0.05) after LL, suggesting that recruitment occurred in
the remaining lobe. When three lobes were embolized with 200-microns glass
beads (0.48 +/- 0.01 g beads/kg body wt), PS decreased (2.1 +/- 0.22 to
0.94 +/- 0.09 ml/s; P less than 0.05), but Kf was not altered (1.01 +/-
0.17 to 1.04 +/- 0.18 g.min-1.cmH2O-1). The constancy of Kf after GBE
implies that the vascular pressure increase during the Kf measurement was
transmitted to both blocked and flowing vessels and thereby measured the
same filtration area before and after GBE. PS decreased significantly after
GBE because of a loss of perfused surface area by the beads blocking flow
in small arterial vessels.(ABSTRACT TRUNCATED AT 250 WORDS)
