How does dialysis work?
To put it simply, dialysis cleans our blood of toxins so that our kidneys will no longer be overloaded by the job. Our kidneys are the organs that filter our blood and absorb the toxins so they do not hurt our body. Unfortunately, especially over time and without proper eating and water-drinking habits, our kidneys can get overloaded with toxins. Just like an overloaded vehicle’s engine would break under the strain, our kidneys start to fail from handling too much toxins.
Dialysis reroutes our blood through cleansing instrument outside our bodies, and returns clean blood into our bodies. The overloaded kidneys have a chance to recover, or at the very least our bodies are not hurt by the toxins entering them. Besides kidney failure, there is also chronic kidney disease, and end-stage renal disease.
When was kidney function discovered?
Our kidneys were suspected as filters for our blood as early as 130–201 AD, by Galen of Pergamum. By studying the anatomy of other mammals, as well as blood flow and the production of urine, early physicians knew quite early on about kidney problems.
To bring it from there to dialysis, however, is a whole other story.
The Father of Dialysis
Thomas Graham, a Scottish chemist in the 19th century, is called the Father of Dialysis. His contribution was not towards solving kidney diseases, but to the science of dialysis itself. He observed that body fluids could be passed through semi-permeable membranes in order to filter them of impurities. Because of this scientific discovery, dialysis was performed on some animals by John Abel and others in 1913 to clean their blood of impurities, although not necessarily to treat kidney failure.
Treating Blood Outside the Body
The moment our blood exits our body, our bodies register the loss as an injury and immediately fights to clot the blood to keep it from flowing out. As a result, even in the early days of dialysis, scientists were aware they had to use blood thinners. This stopped the blood from clotting, and allowed it to flow freely through the dialysis machine. They used hirudin, which is also what leeches use to stop blood from clotting while they drink.
Georg Haas, a German doctor, was the first to use a dialysis machine to cleanse blood outside the body and return it to treat kidney failure. His first patient, it was believed, was in 1924. Over the next four years, he used dialysis treatment for 6 patients suffering from kidney diseases, and was successful in none of them. However, he discovered that heparin makes a better blood thinner or anticoagulant, because it was already produced in mammals. Humans responded better to this than to an element found in leeches.
In 1945, Dutch doctor Willem Kolff developed a “drum kidney” that not only filtered the blood but rinsed it as well in an electrolyte solution. The science of plastics and other artificial materials had also advanced to the point that less toxins or impurities from the instruments themselves were passing into the blood, which was one of the problems Georg Haas faced. Kolff’s first patient recovered from acute kidney failure, and their kidneys were functioning normally at the time of discharge.
Cleaning Blood of Excess Water
The kidneys cleanse our blood of toxins and also drain it of excess water, so that it can be passed through the body as urine. After the first blood treatments were done, scientists and doctors realized that a non-functioning kidney would also not be able to drain the blood of excess water.
In addition to cleansing the blood, Swedish chemist Nils Alwall proposed a new design that would both clean and drain the blood. The kidney’s function would be so closely mimicked that the body would have nothing to complain about, so to speak, after the cleansing.
Uninterrupted Blood Flow
Dialysis replicates the kidney’s function as closely as possible. Ideally, the body should never even realize that it is not functioning the way a normal body would. Blood flow, cleansing, and filtration are meant to be uninterrupted in the body. How could doctors do more than one dialysis while making the body feel like there was nothing different?
An American scientist, Belding Scribner, discovered one method in 1960. It was a shunt, or a “circulatory short circuit,” that attached one vein to one artery through tubing outside the body stabilized on a small plate. When it was time for dialysis, the shunt would be connected to the dialysis machine, and blood would flow into the machine and then back into the body in as smooth a sequence as possible.
However, this method was prone to infection, as an open wound was in effect being maintained at all times. In 1966, physicians Michael Brescia and James Cimino used needles to draw and then restore blood only when dialysis was needed. This method was less intrusive, did not require open wounds, and was much more sanitary.
The History of Dialysis: Celebrating Our Kidneys
Dialysis is a brilliant invention that saves many lives. However, its development only creates a deeper and deeper regard for our kidneys, which perform the same functions so automatically. The more we know about how our kidneys work, the better we will inevitable become at treating illnesses that relate to these.