controversy persists concerning the mechanisms of edema reabsorption
from the lung and the effect of mechanical ventilation on this process.
Lymphatic drainage probably plays a relatively minor role in
reabsorbing excess fluid, and it has not been possible to show that
increasing serum protein concentrations enhance dehydration of the
interstitium. Simultaneous increases in airspace and pleural pressure
(Pa and Ppl) at constant lung volumes should increase
interstitial pressure, and this would result in the reabsorption of
fluid in accordance with Starling principles if interstitial pressures
rise above pressures in the vasculature. However, increases in
Pa and Ppl above pressures in the vasculature also compress
septal vessels, preventing fluid reabsorption.