Blood-volume monitoring in paediatric haemodialysis

A correlation between relative blood volume (RBV) reduction and adverse intradialytic events has been reported in children. Our aim was to determine whether the shape of the RBV curve and the RBV thresholds discriminated between haemodialysis treatments where patients developed complications and those where they did not. We retrospectively reviewed blood volume records (n = 74), using the Fresenius module. "Treatment complications" were defined as hypotension and/or intradialytic symptoms requiring nursing intervention. Treatments with complications were significantly associated with changes in heart rate (P = 0.05) and steeper decline of the RBV curve in the first hour (P = 0.01), but the final RBV measurement was not predictive (P = 0.27). When receiver operator characteristic (ROC) analyses were used, cut-off RBV thresholds of 88% at the end of the first hour, 84% at the end of the second hour, and 82% at the end of the third hour of dialysis, were able to discriminate between treatments with and without complications, but no RBV values at the end of the fourth hour of dialysis were discriminatory. The RBV curve differed in polyuric patients, such that complications occurred at lower RBV thresholds than in oliguric patients. Evolution of tachycardia and a steeper RBV fall in the first hour of dialysis predicted the occurrence of treatment complications.