Journal of Applied Physiology, Vol 68, Issue 3 1233-1240, Copyright © 1990 by American Physiological Society
Concentration of aerosolized 99mTc-albumin in the pulmonary lymph of anesthetized sheep
B. T. Peterson and K. D. Dickerson
Department of Physiology, University of Texas Health Center, Tyler 75710.
We examined the lymphatic concentration of 99mTc-albumin deposited in the
air spaces of anesthetized sheep to determine whether changes in the
concentration reflected changes in lung epithelial function. Five control
sheep were ventilated with an aerosol of 99mTc-albumin for 6 min, and the
lung lymphatic concentration of the tracer was monitored for the next 2 h.
During the last 45 min the lymphatic concentration stabilized at a value
that was 0.03 +/- 0.01% of the estimated value in the air spaces. Pulmonary
vascular hypertension, induced in seven sheep by increasing the left atrial
pressure 20 cmH2O for 4 h, increased the lung lymph flow from a base-line
value of 3 +/- 2 to 21 +/- 14 ml/h. This caused the concentration of the
99mTc-albumin in the lymph to double to 0.07 +/- 0.03% of the air space
concentration (P less than 0.01). Lung injury induced by infusing 0.08-0.10
ml/kg oleic acid intravenously in seven other sheep increased the lymphatic
concentration of the 99mTc-albumin 10-fold to 0.31 +/- 0.09% of the air
space concentration (P less than 0.01). The increased tracer concentration
in the sheep with pulmonary vascular hypertension could be the result of
the increased lymph flow causing a diversion of tracer into the lymphatics.
However, a mathematical model showed that the 10-fold increase in the
lymphatic concentration in the sheep with lung injury was primarily the
result of an increase in both permeability and surface area of the
epithelium that participated in the transfer of the 99mTc-albumin from the
air spaces into the lung tissue drained by the lymphatics.(ABSTRACT
TRUNCATED AT 250 WORDS)
