PD and HD in combination

Peritoneal dialysis (PD) and hemodialysis (HD) are the most used therapies for endstage renal disease (ESRD). Peritoneal dialysis offers the advantages of long, slow, continuous ultrafiltration and preserve residual renal function (RRF) one of the most important factors affecting outcomes in PD. In contrast, HD offers superior solute removal but with undesirable cardiovascular tolerance of high rates of sodium and water removal. Peritoneal dialysis (PD) represents an effective way to maintain residual renal function and should be the first choice dialysis technique. However, with the loss of RRF, some limitations of PD alone in controlling the uremic state appear. Combination of the two techniques therapies, PD + HD (also called bimodal dialysis BMD), is the simplest way to deal with these limitations. The general prescription for BMD should be 5-6 days of PD and 1 or 2 HD sessions weekly. One of the most important controversy is how to evaluate the adequacy of the combined treatment: some Authors adopted the equivalent renal clearance (EKR), first transforming the weekly PD adequacy index (Kt/V), and then evaluating total clearance from both modalities. However, the EKR may overestimate the dialysis dose. Thus to accurately track dialysis dose some use the total effluent (PD, RRF, and HD) sampling method to yield Kt/Vef and creatinine clearance (CCref).