Studies on the Hemodynamic Consequences of Partial Cardiopulmonary Bypass in the Lamb.

摘要

We studied the distribution of systemic blood flow during veno-arterial extracorporeal membrane oxygenation (ECMO) in newborn lambs. We employed a three compartment model which defined partitioning of blood flow to the heart, upper body (brachiocephalic trunk), and lower body (descending aorta). The method utilized concurrent left ventricular and arterial cannular injections of radiolabeled microspheres to calculate compartment flows and solve the system of equations which defined the partition model. Seven newborn lambs were studied. A baseline microsphere injection (left ventricle, LV) was performed and the animals were then placed on veno-arterial ECMO using right carotid and jugular vein cannulation. The arterial cannula was placed 2-3.5 cm above the aortic valve. After stabilization on ECMO flow rates of 50 and 100 mL/min/kg, differently labeled microspheres were injected simultaneously into the LV and arterial limb of the ECMO circuit. From the flow partition model distribution of blood flow was calculated. We found that ECMO did not change the overall distribution of blood flow to the three compartments studied.