The circulation component will utilize readily available blood pumps that are currently in routine clinical use for a variety of indications.
In general, two types of blood pumps can be used. One type is that of a roller pump, while the other type is that of a centrifugal pump.
The various trade-offs between the two different types of pumps is well beyond the scope of this webpage. However, by considering an analogy known in electronics, one of the differences can be thought of as the difference between constant voltage versus constant current.
This difference becomes quite important because not only is blood being circulated extracorporally, a steady supply of high-flow oxygen gas must also be present, such that the semipermeable membrane separates these two compartments.
The requirement to maintain the structural integrity of an ultra-thin semipermeable membrane that also retains its planar shape without any significant mechanical deformation introduces yet another novel aspect into the invention.
The underlying principle here is that the pressure of the blood on one side of the semipermeable membrane must be equal to the pressure of the high-flow oxygen gas that is streaming on the other side of the semipermeable membrane.
The question then becomes as how to achieve this delicate balance?
The answer is that this can be achieved by using the advantage of the constant flow (“current”) provided by a centrifugal blood pump, together with the emerging technology of piezoelectric pneumatic valves. Along with many other favorable features, piezo valves demonstrate incredibly fast switching speeds that can easily reach into the sub-microsecond range.
Piezoelectric pneumatic valves are rapidly being applied in a variety of settings that include industrial adhesive applications, the production of semiconductors, ophthalmologic surgery, mobile medical ventilators, and in the case of this invention, flow control.