Osmolality Changes during Hemodialysis

Abstract

The influence of both a high-glucose-concentration dialysate (717 mg/dl) and i.v. mannitol (1 g/kg) on the serum osmolality changes in stable patients on chronic dialysis was studied. During regular dialysis serum osmolality fell 10 mosmol/kg H2O. This fall was reduced to 5.2 mosmol/kg H2O when the high-glucose-concentration dialysate was used and to 4.3 mosmol/kg H2O when i.v. mannitol was used. When the 2 methods were combined, the serum osmolality fall was reduced to 1.7 mosmol/kg H2O. The clinical signs of disequilibrium declined (67-10%) in parallel with the decline in serum osmolality changes. This fall was independent of the ultrafiltration rate. A high-glucose-concentration dialysate and i.v. mannitol can each reduce the osmolality changes that occur during hemodialysis, but when used alone, i.v. mannitol was more effective of the two. The reduction of osmolality changes also led to reduction of the mild clinical signs usually associated with disequilibrium.