Cardiopulmonary dynamics during pumpless arteriovenous bypass for respiratory assistance.

The effect of a pumpless arteriovenous bypass with a microporous membrane oxygenator (MO) on the cardiopulmonary dynamics of dogs revealed an increase in cardiac output and cardiac work proportional to the increase in extracorporeal blood flow. Several current MOs offer so little resistance to blood flow that shunt flows exceeding a third of the normal cardiac output can easily be obtained. This should be enough for CO2 extraction covering metabolic production, and would add a non negligible amount of O2 to the blood.