Changes in body compartments on different types of haemodialysis.

Changes in plasma volume (PV), extracellular volume (ECV) and intracellular volume (ICV) were studied in seven patients on conventional haemodialysis (HD) and in six patients on stable hypertonic HD. Weight loss and ultrafiltration were similar in both groups. Before HD the spaces of 125RISA (PV), 35SO4Na2 (ECV) and 3H2) (total body water, TBW) were simultaneously determined ICV = TBW - ECV. At the end of HD the space of 35SO4Na2 was again tested. PV and ECV diminished more on conventional HD than on hypertonic HD, whereas ICV increased on conventional HD and decreased on hypertonic HD. The handling of plasma osmolality during HD is an effective method for modifying transcompartmental body fluid shifts in HD by distributing weight loss between intracellular and extracellular spaces allowing for a better maintenance of plasma volume.