[The early history of the artificial kidney].
Only very few remember Georg Haas as the scientist who--in 1924--was the first to successfully conduct an extracorporal hemodialysis on a patient in Giessen. Haas began his experiments in 1914 shortly after joining the Medical Clinic of the University of Giessen. Neither protocols nor any of the set-ups were preserved from these early experiments. In addition, the WW1 interrupted Haas' early experiments between 1917-1919. Until 1923 Haas himself never mentioned his early experiments. "Outside circumstances" and a "shortage of materials" (hirudin) prevented Haas from continuing his work on hemodialysis. Also, the early trials had disappointing results as the experimental animals, mostly dogs, died after a few hours. The hirudin preparations Haas had used turned out to be toxic. While the toxicity of the hirudin preparations prevented the application of dialysis in humans early on, the war with its many cases of nephritis provided new inspiration to develop dialyzing techniques. Haas experimented with reed tubes, calf peritoneum and paper membranes. None of these worked satisfactorily. Not until Pregl introduced collodion tubes was the first barrier overcome. Haas started experimenting with collodion tubes produced by himself. However, the toxicity problem with the hirudin preparations remained. Haas resumed the hemodialysis experiments in 1923. Significantly, 1923 was the year when Necheles published his work describing an alleged purified leech extract. Necheles' paper also described American experiments that focused on dialysis in animal trials. It was J. Abel of Baltimore who informed Haas that purified hirudin was available. After learning of this availability through the American studies in 1924, Haas conducted his first hemodialysis on a uremic patient in late 1924. This experiment lasted only 15 minutes and was without complications. A second dialysis attempt followed in 1925 and even lasted 30 minutes. Finally, four further experiments followed in 1926. The turning point was the availability of purified heparin from 1925 on. Haas, who in 1924 conducted the first dialysis using hirudin, in 1927 conducted the first hemodialysis using heparin. Further hemodialysis treatments followed. Haas concluded: "The problem of hemodialysis is still in the first steps of practical application. Nevertheless it could be shown that hemodialysis has developed sufficiently to find applicability even in patients with serious kidney ailments and irritable heart...Hemodialysis was not only well tolerated but also brought a temporary subjective improvement. Of course, the technical aspects of hemodialysis still need improvement and further development to qualify as detoxicant therapy." A look at the early history of the artificial kidney and its applicability to humans reveals that J. Abel conducted the first hemodialysis on experimental animals. It also becomes evident that Haas conducted the first hemodialysis in humans. The American experiments pursued the quantitative optimization of the method in animal trials, while Haas' experiments focused on the development of a therapeutic method following the principle "primum nil nocere."