Increase in blood volume during dialysis without ultrafiltration

Combined dialysis and ultrafiltration leads to more frequent episodes of hy potension than isolated ultrafiltration, It has been suggested that decreas ed plasma volume preservation could be responsible for this phenomenon, The present study evaluates the effects of diffusive dialysis on the changes i n relative blood volume (RBV), Six stable hemodialysis patients, without th e need of ultrafiltration, were studied during 10 sessions of diffusive dia lysis (bicarbonate) lasting 4 h, REV was monitored continuously by measurem ent of hematocrit, During the Ist and 2nd h REV increased by 2.4 +/- 1,4 an d 2.5 +/- 0.8% respectively, returning to baseline levels at the end of dia lysis, No changes in blood pressure or heart rate were noted, We conclude t hat during diffusive dialysis without ultrafiltration REV is increased, A d ecrease in vascular resistance, or changes in regional blood distribution c ould explain these findings. Copyright (C) 2001 S. Karger AG, Basel.