History of hemodialyzers' designs.

Accumulation of knowledge requisite for development of hemodialysis started in antiquity and continued through Middle Ages until the 20th century. Firstly, it was determined that the kidneys produce urine containing toxic substances that accumulate in the body if the kidneys fail to function properly; secondly, it was necessary to discover the process of diffusion and dialysis; thirdly, it was necessary to develop a safe method to prevent clotting in the extracorporeal circulation; and fourthly, it was necessary to develop biocompatible dialyzing membranes. Most of the essential knowledge was acquired by the end of the 19th century. Hemodialysis as a practical means of replacing kidney function started and developed in the 20th century. The original hemodialyzers, using celloidin as a dialyzing membrane and hirudin as an anticoagulant, were used in animal experiments at the beginning of the 20th century, and then there were a few attempts in humans in the 1920s. Rapid progress started with the application of cellophane membranes and heparin as an anticoagulant in the late 1930s and 1940s. The explosion of new dialyzer designs continued in the 1950s and 1960s and ended with the development of capillary dialyzers. Cellophane was replaced by other dialyzing membranes in the 1960s, 1970s, and 1980s. Dialysis solution was originally prepared in the tank from water, electrolytes, and glucose. This solution was recirculated through the dialyzer and back to the tank. In the 1960s, a method of single-pass dialysis solution preparation and delivery system was designed. A large quantity of dialysis solution was used for a single dialysis. Sorbent systems, using a small volume of regenerated dialysis solution, were developed in the mid 1960s, and continue to be used for home hemodialysis and acute renal failure. At the end of the 20th century, a new closed system, which prepared and delivered ultrapure dialysis solution preparation, was developed. This system also had automatic reuse of lines and dialyzers and prepared the machine for the next dialysis. This was specifically designed for quotidian home hemodialysis. Another system for frequent home hemodialysis or acute renal failure was developed at the turn of the 21st century. This system used premanufactured dialysis solution, delivered to the home or dialysis unit, as is done for peritoneal dialysis.