Technology: Kidneys–The Present of Dialysis

Abstract

Dialysis, in its routine 3 x week manifestation, undoubtedly is life saving. The therapy is limited by a number of factors that persist despite the development of safe machines and highly efficient dialyzers. The turnover of known, and very likely, many unknown uremic toxins, is rapid so that 3 x week dialysis is accompanied by relatively high levels of these substances. Only the lower part of the range of molecular weights of those putative uremic toxins, which are small proteins, are removed by current therapies. For substances such as phosphorus, long dialysis is successful in removing the excess retained dietary phosphorus, perhaps the only proven uremic toxin. The difficulty of achieving a normal extracellular volume is probably a major factor in the progression and poor outcomes of cardiovascular disease despite the potential improvement with management of hyperlipidemia, inflammation, potential arrhythmias, and cardiac failure due to other pathogenetic mechanisms. New developments in understanding of Vitamin D metabolism, Ca receptor inhibitor drugs, and control of hyperphosphatemia may reduce the problems of kidney bone disease and the adverse cardiovascular effect of calcium phosphorus disposition. Dialysis more frequent than 3 x week is already routinely, if only infrequently, used to deal with the very large volume or overhydrated patient. However, daily dialysis--whether short or long-is now beginning as a therapy with a large randomized NIH trial in the offing. Currently, the net growth of dialysis is approximately 4% a year, but it would not be surprising if there were a gradual increase in growth rates as CKD patients live longer due to control of cardiac disease. Eventually, the treatment of early kidney disease should reduce the dialysis population, particularly if diabetes can be better controlled or even prevented. The dialysis aspect of nephrology as a profession for physicians, nurses, and technicians appears to be on a long course with increasing demand and the need for applying what is already known, while awaiting new technical developments. Wearable artificial kidneys, involving the application of technology and use of new materials, are currently being investigated. The presence of nephrologists during the actual dialysis treatment is certainly not as evident as it was in the past. Reimbursement methodology has ensured at least a minimum of documented visits by nephrologists or nurse practitioners to the dialysis patient during treatment. It is controversial as to the value of this, but evidence has been presented that certain outcomes, such as use of appropriate dialysis dose and blood chemistries, are improved by more frequent visits. The present is over.