Landé-Edwards membrane oxygenator without pump as total lung prosthesis.

Fourteen anesthetized dogs remained in apnea for 1 to 4 hours on total extracorporeal breathing through a Landé-Edwards membrane oxygenator (LEMO). The LEMO was directly perfused by the right heart in total pulmonary bypass, without a pump or reservoir, as an external artificial lung. A 2 sq. M. LEMO proved adequate for a dog weighing 10 kiolgrams. Pulmonary arterial pressure increased 60 per cent of the base-line value at the start of bypass because of transitory LEMO resistance, three times the normal pulmonary resistance; the pressure then returned to the initial value. Systemic arterial pressure dropped to 61 per cent on bypass. The heart did not fail. Cardiac output, central venous pressure, and the electrocardiogram remained unchanged. PO2 at the LEMO outlet was more than 200 mm. Hg. Oxygen transfer was less than 20 ml. per minute per square meter because of hemodilution and hypothermia. Dogs survived if bypass was arrested after 1 hour; if not, they died after an average of 3 hours, 20 minutes on bypass.