Beyond Kt/V: redefining adequacy of dialysis in the 21st century.

I presume that every dialysis patient needs a minimal amount of dialysis, since less dialysis will lead to death. Until we come up with a better index, for hemodialysis, I propose that we should return to Scribner's 1974 recommendation on adequacy of dialysis and concentrate on the homeostatic function of the kidney, as indicated in Table 1. For those who still want to measure dialysis dose by Kt/V, the optimal dose for HD is a Kt/V of 1.2/treatment and for PD 1.7/week. None of these would be adequate without good UF and control of patients' fluid status. Frequent (4, 5, 6 or 7 days/week) and prolonged dialyses (5-8 hours) should be the norm and I believe that the Hemodialysis Product should be used as a guide, pending confirmation by prospective studies. A high hemodialysis product reflects much more closely the function of the normal kidneys than 3-4 hours of dialysis three times a week with a Kt/V of 1.2 per session. Peritoneal dialysis that is already continuous needs to improve its efficiency. For PD patients, I believe that the total daily volume (Kt) might be a better index of adequacy, especially if it is combined with a good ultrafiltration (at least of 1 L/day) and blood pressure control. Of course, this has to be confirmed in the future. In the anuric patients, the daily volume can be kept to 8 L/day if the patient is free of symptoms, but should be increased to 10-12 L/day for CAPD and 15-20 L/day for APD patients if they develop symptoms of underdialysis and fluid overload.