A bit of context
Hemodialysis is the most common treatment for kidney failure. It is done by circulating the blood through a semipermeable membrane to remove waste from the blood, thereby supplanting the function of the kidneys. Although in theory this is an easy process, in practice it is not so easy to create a hemodialysis machine. Proof of this is that the history of hemodialysis has only two hundred years. We’ll take a look at the most important milestones of its history in this post.
On the origins and early history of hemodialysis
Thomas Graham, a Scottish chemist and Fellow of the Royal Society of England, is considered by many as the father of dialysis. Graham laid the foundations of colloid chemistry demonstrating, among other things, that the vegetable parchment acted as a semipermeable membrane. He tightened this parchment on a cylindrical wooden frame and placed it in a bowl of water. After pouring on the parchment a liquid that contained crystalloids and colloids, he found that, over time, only crystalloids passed through the parchment.
In another experiment, he showed that the crystalloids in urine passed through a semipermeable membrane into the water, which left a residue of urea crystals once it evaporated. Graham gave this phenomenon the name of “dialysis” (from the Greek “dià”, meaning “through”; and “lỳsis”, meaning “splitting” or “loosening”). However the experiments conducted by Graham had no practical clinical application until half a century later.
In 1913, the American pharmacologist and biochemist John Abel and his colleagues performed the first dialysis in animals, and described a series of experiments with a primitive device which they called artificial kidney. But it was the German medical doctor Georg Haas who, based on the ideas of Abel, practiced in 1926 the first dialysis in a human being. The dialysis lasted 35 minutes, and, except for a febrile reaction, the patient managed to tolerate the procedure. Subsequently, Haas would perform another two dialysis sessions, with two uremic patients using the newly discovered heparin.
It is in the 1940s, with the advent of Willem Kolff’s rotating-drum kidney and the techniques developed by Gordon Murray when hemodialysis becomes an accepted procedure for clinical application. However, at first, it was not a widespread practice because of the many technical problems it had, mainly the lack of effective anticoagulation, the appearance of numerous infections and the fact of not having an efficient, stable vascular access that would allow the execution of hemodialysis as yet another substitute treatment.
The late twentieth century
In 1955, hemodialysis had already been implemented in a few hospitals, but only in exceptional cases, since many considered it a laborious, expensive and dangerous experimental procedure. However, the successful usage of this technique in many cases of acute renal failure prompted a new impetus for its development.
The application of hemodialysis in patients with chronic renal failure had to wait until 1960. That year, Belding Hibbard Scribner used the first external bypass, built with thin-walled Teflon. The Scribner bypass was a U-shaped cannula that connected the vessels at the wrist (radial artery and cephalic vein or ulnar artery and basilic vein) through an external, synthetic bridge (external arteriovenous fistula) permanently installed, so that the artificial kidney could be connected as often as necessary. The bypass was designed so that, when not in use, the cannula served as an extension of the circulatory system: the U-shaped section drove the artery blood back into the vein. When the dialysis was done, the U-shaped portion could be disconnected and the artery and vein connected to the artificial kidney. The bypass could be used immediately and did not require puncturing the vessels, since the disconnection from the bridge allowed the extraction of blood from the arterial branch, which after passing through the dialyzer, once purified, returned by the venous branch to the patient.
The appearance of Scribner’s bypass allowed repeated access to the bloodstream and the birth of the first regular hemodialysis program, which was created in Seattle in 1961, in the hospital of the University of Washington. A procedure to replace the kidney’s purifying function had finally been standardized, thus preventing the deaths of patients with chronic renal failure and, in a matter of years, many hemodialysis units were created.
However, the problem of finding a suitable vascular access was not completely solved, since the Scribner’s bypass limited the patient’s movements, required a meticulous cleaning and would often lead to infections and thrombosis. These problems were solved in 1966, when Cimino and Brescia describe the arteriovenous fistula (AVF), which allows for an adequate blood flow, has low incidence of infectious and thrombotic processes and is well tolerated by the patient.