Effects of blood flow reduction and lymphatic ligation on coronary transport in dogs

Changes in regional plasma extravasation in rats following endotoxin infusion

Regional differences in plasma extravasation during endotoxin shock in rats and a possible relationship with changes in regional blood flow were studied with radioactive isotopes (125I-HSA, 51Cr-labeled red blood cells, microspheres) in anesthetized rats (pentobarbital). Shock was induced by intravenous infusion of endotoxin (Eschericia coli; 10 mg X kg-1) for 60 min (starting at t = 0); at t = 120 min, the experiments were terminated. These rats (n = 8) were compared with time-matched control rats (n = 8). A third group (rats killed 7.5 min after injection of 125I-HSA, i.e., no extravasation; n = 8) served as baseline. The amount of plasma extravasated in 2 hr of endotoxin shock was significantly increased over control values in skin (by 67%), colon (88%), skeletal muscle (105%), stomach (230%), pancreas (300%), and diaphragm (1300%). Losses of 125I-HSA into intestinal lumen and peritoneal cavity had also increased over control values by 146 and 380%, respectively. Blood flow was compromised in most organs except heart and diaphragm. Extravasation when normalized for total plasma supply was correlated with total blood supply; the more the blood supply decreased, the higher the normalized extravasation. In the diaphragm, however, blood supply and plasma leakage increased together. Decreased blood supply and plasma extravasation may be related but they could also be simultaneously occurring independent phenomena with a common origin.

Lung vascular transport at controlled pressures with reduced coronary flow in sheep

This study was performed to measure the effects of sustained coronary flow reduction on lung lymph flow and protein clearance at normal and elevated lung microvascular pressures. Eleven halothane-anesthetized sheep were provided with lung lymph and carotid-to-left-anterior-descending coronary artery cannulas. Six sheep (ischemic group) were observed in a protocol of five periods, each of 2 hr duration: baseline, left atrial pressure (PLA) increased by mitral valve obstruction, return to baseline, reduced coronary flow, and reduced coronary flow plus increased PLA. Five sheep (control group) were studied in an identical protocol except that coronary flow was not reduced. PLAS were equal in the second and fifth periods. Lung lymph flow QL and protein clearance (QL times the lymph-to-plasma protein concentration ratio) normalized to second baseline were greater during ischemia than in the comparable control period, and clearance was also greater during the second increased-pressure period. We conclude that reduced coronary flow is related to sustained, significant increases in lung vascular transport at elevated as well as at normal vascular pressures.