Exclusion of Heart and Lungs From Circulation in the Hypothermic, Closed-Chest Dog by Means of a Pump-Oxygenator

Abstract

The safety and efficiency of a pump-oxygenator based on the principle of gas dispersion in blood has been tested in the closed-chest dog by perfusing blood from artery to artery and from vein to artery without and with oxygenation. It could be shown that full oxygenation by the instrument is necessary if dogs are to survive the shunting of large amts. of venous blood into the arterial tree for prolonged periods of time. The heart and lungs of dogs were excluded from the circulation by occluding the venous return to the right heart with specially designed cellophane balloon catheters and by maintaining circulation and oxygenation of blood by means of the pump-oxygenator. If hypothermia was induced by cooling the blood in the extracorporeal circuit, the flow rate could be reduced to the diminished cardiac output prevailing at that low body temp. Thus, at 30[degree]C body temp., half of the normal cardiac output was required to pump and oxygenate outside the body in order to cover the O2 requirement of dogs and to effect consecutive survival.