Reperfused human umbilical cords: hydrodynamic and hemolytic analysis of the ex vivo model for umbilical cord ECMO cannulation.

BACKGROUND: A new type of umbilical vascular access routes is needed for the extracorporeal blood circuits, which are part of artificial placenta treatment. So far, devices and techniques for this purpose have been developed and tested only in large animal models or simulators. We have previously reported a test setup for the development and training of umbilical vessel cannulation on reperfused human umbilical cords. It allows the simulation of the insertion of large-bore cannulae into the perfused umbilical arteries and vein, as it is planned to be performed in an ex utero intra partum procedure. We present an evolved version of the test stand with reduced priming volume, resistance and hemolysis. METHODS: Standardization and optimization of cannulae and tubing reduced flow resistance and priming volume. Hematocrit was adjusted to 0.3. Fourteen umbilical cords were harvested, prepared, visually analyzed, and used to validate the setup. Seven circuits were primed with autologous placental blood at a hematocrit of 30%, and seven were primed with saline solution. A volume flow of 70 mL/min was targeted, and pressures and hemolysis were measured. RESULTS: Differences in vessel structure and coiling were identified. The measured pressure drops were in a physiological range. There was no significant hemolysis caused by the cannulas or the umbilical cord compared to the tubing, reservoir, and blood pump. CONCLUSION: The test stand for reperfused human umbilical cord specimens primed with autologous placental blood or saline solution can provide a biosimilar model for medical therapies with low ethical concerns and patient risk.