Over 10 years ago, I wrote about the differences of the Seattle program with Belding Scribner and the Boston, Peter Bent Brigham Hospital Nephrology group in a blog I called the Tale of Two Cities. This was the beginning of the debate between long, slow and more frequent dialysis against the short, fast and violent dialysis practice patterns prevalent today in the US. While exploring historical records of the start of chronic dialysis with the Scribner Shunt in 1960, it became clear that the well intentioned, but erroneous development of the Kolff Rotating Drum kidney and the Kolff Twin Coil kidney were based on high Urea clearances, with shorter dialysis sessions. These two Kolff kidney machines not only served as a basis of acute kidney care around the world during the 1950's, but it also paradoxically began the short and infrequent treatments that has led to the worst outcomes of all the High Income Nations.
Belding Scribner wrote an historical account of why the Seattle program chose long, slow and "frequent" (Thrice weekly). Scrib noted that all of the complications that were involved in the initial treatment protocols came from the first patient, Clyde Shields. Their decisions included:
1) Long treatments instead of short. This was chosen with the Kiil kidney because it allowed a single pool of dialysate for the entire treatment instead of redoing the pool every two hours as with the Kolff machines. The long and slow treatments serendipitously promoted clearance of the middle molecules involved in uremic toxicity.
2) Long and slow also promoted slower removal of excess fluid without causing cardiovascular collapse.
3) Thrice weekly, long and slow was chosen to overcome uremic neuropathy and became a physiologic measure of dialysis dose which is still used today.
Willem Kolff worked closely with the Boston program and John Merrill beginning in 1948. The primary focus that Kolff considered in his machine designs was improved removed of Urea. Both the Kolff rotating drum and the Twin Coil Kidney had three times the clearance of Urea than the Kiil dialyzer which at that time seemed to be an important consideration, but we now know that urea kinetics do not correlate closely to survival. TIME and Frequency of dialysis sessions are much more important, independent factors in survival. Scribner noted this in his historical account in 2004:
Scribner BH, Cole JJ, Ahmad S, Blagg CR. Why thrice weekly dialysis? Hemodial Int. 2004 Apr 1;8(2):188-92. doi: 10.1111/j.1492-7535.2004.01094.x. PMID: 19379416.
"The fact that creation of our continuous flow hemodialysis system preceded development of the arteriovenous Teflon shunt for chronic dialysis unknowingly provided a great advantage over other dialysis programs that were using the Kolff rotating drum dialyzer or the twin-coil system. These dialyzers were very useful in the treatment of acute renal failure but unsuited to the treatment of chronic renal failure. Both required a dialysate bath change every 2 hr for a 6-hr dialysis and the twin-coil system also required a blood pump, adding complexity to the treatment. Furthermore, these dialysizers needed to be primed with 1 unit or more of blood, most of which could not be returned to the patient at the end of the dialysis. Although both had urea clearances more than three times that of the Skeggs-Leonards and the Kiil dialyzers, the total urea clearance per treatment was very similar.
Although we did not realize it at the time, our continuous-flow system also allowed a slight but perhaps crucial increase in the removal of toxic middle molecules as a result of dialyzing for 24hr once a week compared with 4 to 6hr treatments with the twin-coil system."
Thus began the debate on urea kinetics vs longer, slower and more frequent as the correct measure of dialysis dosage. There is little doubt that Scribner in retrospect chose well, and Kolff chose poorly in designing his machines based on urea removal which can occur rapidly and thoroughly with little time or frequency. While the rest of the developed nations followed the lead of Scribner and the Seattle program with longer, slower and more frequent treatment protocols, the US followed the lead of Kolff and Brigham nephrology doctors who used the Kolff twin-coil kidneys for nearly a decade of the chronic kidney programs. The Harvard/Brigham influence over US dialysis policy based on shorter and less frequent 9-12 hour weekly treatments began with Kolff who had 8-12 hours of treatment with his twice weekly 4-6 hour twin-coil kidney treatment protocols. These machines and schedules were excellent at removing urea and normalizing other laboratory parameters, but they were not based on the same clinical goals of the Scribner program to alleviate all symptoms of uremia with treatment including relief of HTN and improvement of uremic neuropathy.
We are still reaping death and deficiency from the decision by Willem Kolff believing that more rapid removal of urea would improve access, reduce costs and provide optimal care to more people. While Kolff did improve access and reduce costs, by focussing on a laboratory parameter, urea removal, Kolff inadvertently began a debate that remains unsettled and littered with the bodies of tens of thousands of patients suffering from the effects of too short and too infrequent dialysis sessions even though "the labs all look good."
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