Extravasation of albumin in tissues of normal and septic baboons and sheep.

Extravasation of albumin was measured in the tissues of normal and septic baboons and sheep. A group of normal animals (4 baboons, 4 sheep) was anesthetized for 6 hr and then given radioactively labeled albumin and red blood cells intravenously. The labeled albumin and red blood cells were allowed to equilibrate for exactly 15 min, at which time the animals were deliberately killed. Volumes of distribution of labeled albumin and red blood cells were then determined in the lungs, heart, liver, spleen, brain, and skeletal muscle of the baboons and in the lungs, heart, liver, and spleen of the sheep. Another group of animals (6 baboons, 14 sheep) were made septic by infusing live Escherichia coli organisms. The animals were resuscitated and volumes of distribution of albumin and red blood cells determined as in the normal animals. The volume of distribution of albumin was greater than the volume of distribution of red blood cells in all tissues in both species, both in control animals and in septic animals, with the exception of the spleen and skeletal muscle of the baboons and the spleen of the sheep. That is, albumin extravasated readily in most of the tissues of the animals, even within only 15 min of equilibration. There was moderate but significant extravasation in the lungs, heart, and brain. There was marked extravasation in the liver. Extravasation tended to be more pronounced in the septic animals. With this extensive degree of albumin extravasation, administration of albumin to patients, especially septic patients, is unlikely to prevent edema except in the spleen and skeletal muscle.