Am. J. Respir. Crit. Care Med., Vol 153, No. 6, 06 1996, 1965-1971.
Acid aspiration results in ileal injury without altering ileal V(O2)- D(O2) relationships
ED Crouser, MW Julian, SE Weisbrode and PM Dorinsky
Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43201, USA.
Systemic organ endothelial injury and V(O2)-D(O2) relationship alterations
occur frequently in the setting of acute lung injury, and they are believed
to play an important role in the pathogenesis of the multiple organ
dysfunction syndrome (MODS). However, the relationship, if any, between
systemic organ endothelial injury and V(O2)-D(O2) relationship alterations
remains unknown. We hypothesized that microvascular endothelial injury and
attendant interstitial edema would result in increased diffusion distances
for oxygen and altered systemic organ V(O2)-D(O2) relationships. To test
this hypothesis, we utilized the in situ autoperfused feline ileal
preparation to evaluate ileal V(O2)-D(O2) relationships in control animals
(n = 5) and in animals with HCl-induced acute lung and systemic organ
injury (n = 5). As expected, ileal endothelial protein permeability (CL/CP)
was increased in HCl-injured animals compared to control animals (0.187 +/-
0.024 versus 0.097 +/- 0.009; p < 0.01). However, contrary to our
original hypothesis and despite marked morphologic and endothelial protein
permeability alterations, ileal V(O2)-D(O2) relationships were not altered
in the HCl-injured animals. Moreover, V(O2)-D(O2) relationships in the
ileum remained unchanged even when ileal venous pressures were increased to
15 mm Hg. Taken together, these findings do not support an important role
for oxygen diffusion limitation in the pathogenesis of altered systemic
organ V(O2)-D(O2) relationships.
