THIS PAPER is a general review of the development of the artificial heart-lung to facilitate open-heart surgery. At the close of World War II many centers began investigating the possibility of total cardiac bypass. Oven the past decade, pump oxygenerators of various types have become popular and recent clinical successes throughout the world have given further impetus to the study of problems posed by the artificial heart-lung apparatus.
The subject divides itself into three separate parts, the first two being concerned with the maintenance of life in an experimental animal during a total cardiac bypass. One must take all the blood from the animal and return it to the animal by means of a pump. Secondly, one must oxygenate the blood before returning it. The third part of the problem confronting the surgeon is the selection of cases and correction of defects in human subjects.
The pumping mechanism must duplicate as nearly as possible the action of the chambers of the heart. Pumping action must be smooth so as to prevent hemolysis and to avoid turbulence with thrombosis. It is not difficult to construct a pump with which hemolysis can be kept to relatively negligible amounts. Most of the pumps in use throughout the world give an hemolysis of less than 50 mg of hemoglobin per 100 ml of blood, which is perfectly safe. Turbulence with thrombosis can be overcome by removing valves inside the stream and placing valves outside of, rather than within the stream of blood. Furthermore, heparinization of the blood lessens the tendency to thrombosis.
- Copyright © 1957 by the American Academy of Pediatrics