Journal of Applied Physiology, Vol 52, Issue 1 260-266, Copyright © 1982 by American Physiological Society
Effect of interstitial fluid (kerosene) on pressure-volume characteristics of rat lung
W. F. Urmey, S. M. Scharf, R. Brown, D. Carlson and P. Song
Although pulmonary interstitial edema has been estimated to decrease
pulmonary compliance (CL), it has been experimentally difficult to
demonstrate whether the observed changes in CL are directly due to the
presence of interstitial fluid or if they result instead from concomitant
pulmonary vascular engorgement and/or alveolar edema. Since
kerosene-inflated lungs do not leak, we were able to use kerosene to
measure the effect on CL of the accumulation of interstitial fluid
(kerosene) in the postmortem rat lung. Pressure-volume (PV) studies of the
lung were done during the progressive increase in interstitial fluid
(kerosene). Analysis of the deflation limbs of the quasistatic PV curves
obtained following serial inflations with kerosene indicated that the
maximal volume of kerosene [MV35, equal to the maximum tissue plus airway
volume at a transpulmonary pressure (Ptp) of 35 cmH2O] was 3.8 +/- 1.2 ml
(31.0 +/- 11.8%) greater than TLC35 [air volume at Ptp of 35 cmH2O prior to
kerosene inflation]. The increases in interstitial kerosene volume had no
effect on kerosene PV characteristics, as was demonstrated by superimposing
lung PV curves obtained at various states of interstitial filling. We
conclude that the interstitial compartment is large and very compliant and
that the presence of even great amounts of fluid limited to this
compartment does not restrict lung expansion.
