Learning from history to improve the performance of blood purification devices and dialysis membranes: from engineering points of view.

Abel JJ, Rowntree LG and Turner BB (Baltimore Trio) proposed the concept of vividiffusion and developed a vividiffusion apparatus in 1912. In a 1914 paper, they laid out the most important rule of device design. We named this rule an ART law taken from the initials of the Baltimore Trio. The ART law means that a blood purification device with a shape that can secure as large a dialysis membrane area as possible for as small a volume of blood filling as possible will achieve high dialysis performance. Rather than using 8 mm inner diameter collodion tubes in the original vividiffusion apparatus, the solution to the device shape that fits this rule is to hold down the tube from both top and bottom to make it as flat as possible, or if it is a flat membrane, to bring two flat membranes as close together as possible, and in the case of tubes and hollow fibers, to make their inner diameter as small as possible of approximately 200 μm. In other words, the dialysis performance is greatly improved by narrowing the blood flow path. This is exactly the ART law, predicting the shape of today's blood purification devices.