EXTRACORPOREAL circulation produces trauma to the blood, and the by-products of this trauma may be deleterious to the body. The feasibility of diverting the animal's blood from the circulation while perfusing with an artificial-plasma red-blood-cell mixture and then removing this mixture while readministering the animal's unperfused blood was investigated. Such a technique should lessen the volume of harmful by-products of blood trauma remaining in the animal's body following extracorporeal circulation.
Artificial Plasma.—It was found necessary to modify the formula for the plasma substitute originally devised by Dahlback and his co-workers. Packed red blood cells were added to this solution in sufficient quantity to give a hematoerit level of 20% to 30% (Fig. 1). The pH of the cells was adjusted to 7.4 with tromethamine (Talatrol) prior to their addition to the solution.
Heart-Lung Machine.—A DeWall-Lillehei type bubble oxygenator was modified to provide a reservoir to receive and hold the