Athena’s Heirs: The History of Medical Technology in Canada

Modern artificial kidneys have highly developed control systems. Input and output blood pressure, transmembrane pressure and temperature are carefully monitored, blood leaks are checked photometrically and air bubbles are checked by ultrasound. The dialyzing bath composition is checked continuously and can be altered in a variety of ways to meet the patient’s needs. The most important development has been the ability to control fluid removal precisely during dialysis.

As priming volume, efficiency, and ease of use became increasingly important criteria, the capillary flow dialyser, which readily achieves these objectives, has become the dialyser of choice. The hollow fibre capillary flow dialyser provided the most surface area for the minimum blood volume. This allows dialysis to be completed in four hours instead of twenty-four.

In the early days of dialysis, access to the circulation was obtained by inserting plastic tubes into an artery and a vein. These tubes could be used in acute renal failure but did not permit repeated dialyses for permanent renal failure. In order for chronic dialysis to become a reality, a means of gaining repeated access to the bloodstream was required. The problem was solved by the arteriovenous fistula.