The bacteriology of the blood of dogs with Eck fistula

Abstract

There is an impression, supported by considerable evidence, that organisms from the bowel often enter the portal stream and in the liver are effectively disposed of. In order to test this point it was thought that Eck fistula dogs might furnish proper conditions; at least, it would be of interest to note whether or not bacteria appeared in the general circulation or possibly caused occasional infections in the lungs or elsewhere in such animals. An Eck fistula is an artificial communication between the portal vein and the vena cava with the portal vein ligated above the anastomosis just at the hilus of the liver. This operation destroys the portal circulation so far as the liver is concerned, in that now the flow of blood from the abdominal viscera (except the kidneys and the suprarenal glands) is returned to the general circulation without passing through the capillaries of the liver; in other words, the liver is shunted out of the portal circulation and receives its sole blood supply by way of the hepatic artery, which carries about one-fifth of the quantity of blood that is carried by the portal vein. The anatomic situation of the liver naturally suggested to investigators a protective function. Under normal condition all the products of intestinal digestion and other absorbable substances (except the greater part of the fats) must first pass through the liver capillaries before reaching the tissues in general, while under the conditions imposed by an Eck fistula they reach the tissues first. It has been amply proved that the liver exercises a protective function against certain poisons absorbed from the alimentary tract, especially against certain of the products of protein digestion, such as ammonia. In fact, dogs with Eck fistulas will not tolerate a heavy meat diet. To prove whether or not bacteria actually pass the bowel wall into the circulation and, if so, what influence the liver has on them, we instituted the following experiments on dogs with Eck fistula.