Journal of Applied Physiology, Vol 56, Issue 4 979-985, Copyright © 1984 by American Physiological Society
Lung fluid balance, vascular permeability, and gas exchange after acid aspiration in awake goats
R. Winn, J. Stothert, B. Nadir and J. Hildebrandt
Lung injuries were produced by instilling 2.5 ml/kg of 0.1 N HCl into the
trachea of lightly anesthetized goats with previously implanted lung lymph
fistulas. Lymph flow (QL), lymph-to-plasma protein concentration ratio
(L/P), pulmonary arterial and wedge pressures (Ppa, Pw), percent shunt
(Qs/QT), and postmortem extravascular lung water (EVLW) were then measured
for up to 48 h. QL began to increase within 15 min of injury from a
baseline value of 7.2 ml/h to reach a peak of 231% of base line by 1.5 h,
then decreased to 160% at 24 h and returned to base line by 48 h. Average
L/P increased from 0.66 to a peak of 0.73 at 2 h. Ppa increased from 17.0
cmH2O to a first peak of 25.3 cmH2O at 15 min, then decreased to base line
by 75 min. There was a second rise that peaked at 3 h before returning to
base line at 24-48 h; Pw was unchanged throughout. Qs/QT increased from 8.5
to a peak of 34% at 1 h, then decreased to 15% at 4 h, and stabilized at
17-20% at 48 h. EVLW was 237% of base line at 4 h and declined somewhat but
remained elevated at 194% of base line at 24 and 48 h. Qs/QT was less than
expected based on the reduction in lung volume after aspiration. We
conclude that microvascular permeability was increased after acid and that
a protective vasoconstriction, probably due to local hypoxia, directed
blood away from nonventilated alveoli.
