Anaphylactic Shock and Mechanical Obstruction of the Hepatic Veins in the Dog

Abstract

Summary Mechanical obstruction of the hepatic veins of the dog produces a fall in arterial blood pressure similar to, but not so marked as, that which occurs in anaphylactic shock. The injection of the homologous serum into a sensitized dog while the hepatic veins are mechanically obstructed does not cause an additional fall in blood pressure that can be attributed to the onset of anaphylactic shock. Peptone, on the other hand, does induce a further fall in pressure under these conditions as a result of peripheral dilatation. When the homologous serum is injected into a sensitized dog with the hepatic veins mechanically obstructed and, after an interval of from one to three minutes, the hepatic veins are released either indefinitely, or for fifteen to twenty seconds and then reconstricted, the ensuing fall in blood pressure is, in most animals, greater than that induced by the obstruction alone. Fifteen to twenty seconds is sufficient time for enough of the injected serum in the circulating blood of a sensitized dog to pass through the liver to initiate anaphylactic shock. It is suggested that in anaphylactic shock in the dog very little blood escapes from the liver into the vena cava. It is further suggested that in anaphylactic shock in the dog there is a peripheral dilatation such as occurs after injections of peptone. But before this peripheral effect is induced the injected serum must pass through the liver of the sensitized animal, while in peptone shock this is not necessary.