Rationale for early incremental dialysis with continuous ambulatory peritoneal dialysis.

There are good reasons to suspect that if a weekly Kt/V urea of <2.0 is inadequate for CAPD then it is also inadequate for CRF without dialysis. Spontaneous protein intakes tend to fall below 0.7-0.8 g/kg at these levels in both CAPD and CRF. Low protein intakes can be associated with deterioration in nutritional status and a falling serum albumin. Low serum albumin concentrations at the start of dialysis are associated with increased risk of death during dialysis. Some nutritional problems which develop during conservative management prior to dialysis initiation may not be completely reversible. Since both renal function and CAPD offer nearly continuous urea clearances, it makes sense that targets for adequacy in CAPD should also be targets for initiation of chronic dialysis. At this time, it seems that a weekly Kt/V urea of 2.0 is a reasonable value. There may be reasons why chronic peritoneal dialysis is more suitable than intermittent HD for the initiation of early incremental dialysis. These advantages have to do with the ease of providing small incremental dialysis doses as needed to maintain the Kt/V urea at a level of 2.0 for the kidney and dialysis combined. Early CAPD may be less threatening to residual renal function than HD. Daily CAPD allows early control of sodium and water balance. It also delays the use of blood access sites until larger dialysis doses achieved with HD are absolutely necessary. There may be cost advantages as well. We should abandon the philosophy of initiating dialysis after patients have already suffered the ravages of uraemia and related malnutrition.