Effect of lysophosphatidylcholine on the filtration coefficient in intact dog lungs.

Lysophosphatidylcholine (lyso-Pc) is a lysophospholipid normally found in low concentrations in the lung. At high concentrations lyso-Pc, instilled into the airways, causes pulmonary edema. We tested the hypothesis that the edema caused by lyso-Pc was due to an increase in pulmonary microvascular membrane permeability. In 11 anesthetized dogs we continuously weighed the left lower lobes (LLL) while instilling lyso-Pc (20 mM) into the LLL airways. After 30 min we determined the microvascular membrane fluid filtration coefficient (Kf) from the relationship between the rate of LLL weight gain and the pulmonary microvascular pressure. Kf was not significantly different between the lyso-Pc-treated lobes (0.048 +/- 0.018 ml.min-1.mmHg-1) vs. control lobes (0.067 +/- 0.031 ml.min-1.mmHg-1). Our data do not support the hypothesis that lyso-Pc, instilled into the airways, causes an increase in pulmonary microvascular permeability.