Pulmonary and peripheral lymph protein clearance during bacteremia after surgery

An increase in pulmonary transvascular protein clearance is seen in sheep following postoperative bacteremia. We evaluated whether this increased protein clearance is specific for the lung by comparing in sheep the effect of postoperative bacteremia on both pulmonary and prefemoral lymph protein clearance. Fibronectin, implicated as a factor influencing vascular permeability, was also measured. After intravenous infusion of a sublethal dose of 5 x 10(8) live Pseudomonas aeruginosa (n = 10), pulmonary lymph flow (QL) increased 146% (P less than 0.01), and the lung lymph-to-plasma (L/P) total protein concentration ratio increased 21% (P less than 0.05). This resulted in a 208% elevation (P less than 0.01) in lung protein clearance (LPC = QL x L/P). In contrast, peripheral lymph flow and peripheral protein clearance were not altered. After intravenous infusion of a lethal dose of 5 x 10(9) live Pseudomonas (n = 7), QL rose 243-348% (P less than 0.025), whereas the lung L/P remained at base line, resulting in a 240-358% increase in LPC (P less than 0.025). Again, peripheral lymph flow and protein clearance did not increase. Plasma fibronectin declined slightly after low-dose bacterial challenge but decreased (P less than 0.001) 40% by 4-5 h after high-dose bacterial challenge. After both low- and high-dose bacterial challenge, fibronectin in pulmonary lymph increased (P less than 0.05) relative to total protein. In contrast, no change in peripheral lymph fibronectin was seen. Thus, while postoperative bacteremia increased lung protein clearance, it did not increase peripheral protein clearance, suggesting specificity with regard to the microvascular response to bacteremia.