Lung vascular permeability following progressive pulmonary embolization

Publisher Website
Google Scholar
Abstract
The effects of pulmonary microembolization on the lung fluid exchange were determined. Pulmonary lymph flow (.ovrhdot.Qlym) and lymph-to-plasma concentration ratios (L/P) of protein, albumin and globulin were determined in anesthetized unheparinized sheep after 3 successive i.v. injections at 120 min intervals of 0.3 g/kg of 100 .mu.m glass beads (E1, E2, E3). Steady-state pulmonary vascular resistance (PVR) increased after each embolization from 4.5 .+-. 0.7 Torr/l per min to 5.9 .+-. 1.3 to 11.3 .+-. 3.7 to 19.2 .+-. 3.6 Torr/l per min. .ovrhdot.Qlym increased after E1 from 7.1 .+-. 0.8 ml/h to 12.2 .+-. 2.2, increased further to 16.7 .+-. 2.9 after E2, but declined to 14.6 .+-. 1.5 following E3. L/P ratios for protein, albumin and globulin increased (P < 0.05) following E1 and remained above control levels. Lymph protein clearance (pulmonary lymph flow .times. L/P protein concentration ratio) showed changes parallel to .ovrhdot.Qlym. The decrease in .ovrhdot.Qlym and lymph protein clearance toward control may be due to severe reduction in the filtration area following E3. Microembolization-induced pulmonary edema is probably due to increased endothelial permeability. The finding that size of pores filtering proteins (i.e., increased L/P ratios) and lymph protein clearance increased following small initial increases in PVR suggests that increased pore size and permeability were not due to hemodynamic mechanisms but rather the release of humoral factors secondary to microembolization. Hemodynamic mechanisms may play a role in increasing lung vascular permeability following severe microembolization.

This publication has 0 references indexed in Scilit: