In Silico Simulation Of The Liquid Phase Pressure Drop Through Cylindrical Hollow-Fiber Membrane Oxygenators Using A Modified Phenomenological Model

Low blood pressure drop is an important performance characteristic of a hollow-fiber membrane oxygenator (HFMO). While the application of natural blood corresponds to complex handling procedures, the in vitro investigation of liquid pressure drop is mainly done using water or similar fluids (e.g., normal saline solution [NSS]). In this study, a comprehensive phenomenological model has been proposed to predict the liquid pressure drop through a cylindrical HFMO, considering viscous and inertial resistances in porous media, derived from literature. The results demonstrate that approaches based on Darcy-Weisbach phenomenological equation correlate the most with in vitro experimental investigations using NSS and native porcine blood, in both pediatric and adult commercially available cylindrical HFMOs. Remarkably, this study corroborates theoretically and experimentally that approaches based on Ergun semi-empirical equation fail to predict the liquid pressure drop in cylindrical HFMOs. Moreover, it is shown that the presented phenomenological model is also applicable to cylindrical hollow-fiber heat exchangers, and subsequently, its noticeable effect on total liquid pressure drop through cylindrical HFMOs is demonstrated. The results reveal that this component may contribute to almost half of total blood pressure drop, and therefore, it should be redesigned using other approaches than hollow fibers.