Hydrodynamic characteristics of artificial lungs

An artificial lung is used during cardiopulmonary bypass to oxygenate blood and to control blood temperature. The pressure drop-flow rate characterist ics of the membrane compartment in three hollow fiber membrane oxygenators were determined in vitro to characterize design features. Results are prese nted in a unique dimensionless relationship between Euler number, N-Eu (rat io of pressure drop to kinetic energy), and Reynolds number, N-Re (ratio of inertial to viscous forces), and are a function of the device porosity, ep silon, and a characteristic device length, xi, defined as the ratio of the mean blood path and manifold length: N-Eu . xi/epsilon(2) = alpha + beta/N-Re . epsilon . (1 - epsilon) This dimensionless approach allows us (1) to compare oxygenators independen tly, and (2) to relate water tests to blood.