Reversed Coil Artificial Kidney: Development of a Prototype

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THE artificial kidneys now in use have one common denominator: the blood is confined in a length of cellophane (tubing or sheets) immersed in dialyzing fluid. The reversed coil artificial kidney reverses this concept. The dialyzing fluid is confined within the tubing and the blood is on the outside of the tubing.

The goals of this technic are to reduce the amount of blood needed for priming, to reduce the resistance to blood flow, so that the dialyzer can be used without a blood pump, and to achieve sufficient dialyzance and variable ultrafiltration. The dialyzing unit should be inexpensive and be able to be sterilized after it has been assembled. To have a future in the United States, it must be able to have a long shelf life, be disposable, and be suitable for mass production. Above all other considerations it must be simple and safe to use.

Guarino1 designed an artificial kidney using the reversed technic. However, the dialyzing fluid was pumped through the cellophane tubes under pressure, thus a leak in the tubing would allow the dialyzing fluid to enter the blood undetected. Our reversed coil artificial kidney avoids this hazard by maintaining the dialyzing fluid at a pressure less than the blood pressure. If a leak should occur, blood would enter the dialyzing fluid where it can easily be detected. Collapse of the cellophane tubing is prevented by a supporting plastic screen core within the tubing. The pressure gradient from blood to dialyzing fluid is sufficient to. . .



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