Achieving euvolemia in peritoneal dialysis patients: a surprisingly difficult proposition

Preservation of residual renal function and reduced early mortality rates are likely to reflect the relative ease with which euvolemia can be achieved in peritoneal dialysis (PD) patients. Yet, there is concern that these patients are frequently fluid loaded, fuelled by the problems of ultrafiltration failure and worse survival observed in anuric patients with low fluid removal. In reality, the proportion of PD patients that are overhydrated is not dissimilar to hemodialysis but the challenges in achieving euvolemia might be different. These include (i) the undesirability of driving down the dry weight, in part to avoid excess glucose exposure, in part because there is a trade off in preserving residual renal function, (ii) limitations in our knowledge of how best to measure and apply measurements of fluid status in clinical practice, (iii) limitations imposed by the therapy itself (e.g., membrane function, sodium sieving), and (iv) the influence of hypoalbuminemia on fluid distribution. Treatment options that enable improved fluid management are available (e.g., automated peritoneal dialysis and icodextrin for rapid transporters, dietary salt restriction) or on the horizon (e.g., low sodium dialysates). We now need studies that aid clinicians in their decision making to enable best fluid management in their patients.