(113b) The Evolution of Hemodialysis since Clark Colton's Doctoral Thesis

In 1969, Clark Colton developed the equations governing mass transport in hemodialysis in his Ph. D. Thesis at M.I.T. At that time, hollow fiber dialyzers were not yet available, Medicare did not yet pay for dialysis, and dialysis was provided only to those rich enough to pay for it or those considered most worthy for treatment by special committees.

In 2006, over 320,000 patients in the U.S. and about a million worldwide are kept alive by hemodialysis and peritoneal dialysis. Dialyzer companies worldwide characterize hemodialyzer performance by a so-called KoA, pronounced "Kay-Oh-Ay." Most nephrologists don't know that the "O" is really a subscript, that the K is an overall mass transfer coefficient, and that the A is membrane area, but they do know that bigger and more permeable dialyzers have higher KoA's and generally do a better job of cleaning a patient's blood. Nowadays, monthly urea kinetic modeling is performed on individual patients' data to monitor the adequacy of the dialysis treatment. For example, FMCNA, the largest dialysis provider in the country, uses two-pool urea kinetic modeling for monthly quality reporting. Literally tens of thousands of dialysis nurses and doctors use the terms "single pool Kt/V" and "equilibrated Kt/V" when discussing the adequacy of a hemodialysis dialysis treatment. How many other dimensionless groups have reached such a level of fame?

This talk will cover not only the growth of urea kinetic modeling, but also technological advances such as on-line clearance monitoring, high-flux hollow fibers, and undulated fibers for improved dialysate flow. Sound engineering, based on the concepts in Clark's thesis, has led to substantial improvement in dialysis care. This talk will also cover important trends such as the rise and fall of dialyzer reuse and the recent rebirth of home dialysis. Last, but not least, the audience will be challenged to address the unmet clinical needs that contribute to a mortality rate that remains at over 20% per year despite improvements in therapy.