Safety and Performance Testing in a Full-Scale Novel Oxygenator

To prove safety and efficiency of a novel miniaturized oxygenator concept in in-vitro tests with animal blood using a real-sized prototype followed by acute animal trial. Current numerical simulations and in-vitro tests using downscaled prototypes showed feasibility of the concept.

Efficiency of oxygenators and a potential for miniaturization are strongly affected by the priming volume of the blood defining diffusion length for the oxygen transport. Since characteristic time for diffusion is a square of the diffusion length, the size of the device is strongly affected by this parameter. To develop a novel oxygenator and /or artificial Lungs (AL) with a small priming volume we propose to fill priming blood volume with microspheres ranging from 50 μm to 200 μm in diameter instead of fabrication of hollow fibers with much smaller diameter, which is currently an unsolved technological problem.

Then, blood flows then between hollow fibers and microspheres as a thin film. Thus, diffusion length will be significantly reduced allowing faster blood saturation with oxygen compared against current existing commercial oxygenators. In turn, this allows significant size reduction thus opening a way for the development of implantable ALs. The proposed idea to fill priming volume with microspheres may sound unreasonable since microspheres do not have any functional meaning.

Additionally, at first view microspheres increase the flow resistance and the risk of thrombus formation, that is the major obstacle on the road to develop any blood contacting artificial organ. However, reduced device length decreases the resistance and floating microspheres are able to rotate due to blood flow around them. This rotation prevents existence of stagnation flow conditions, which together with recirculation regions promote thrombus formation. A success of this principle was shown by a first artificial heart valve prosthesis developed in 50’s years of 20th century – the caged ball Starr Edwards mechanical heart valve.