Reliability of haemodialysis urea kinetic modelling in children

Abstract

The reliability of urea kinetic modelling (UKM) in paediatric haemodialysis was tested by comparing results of the classic variable volume model (UKM3), a recently introduced two-sample modification of this (UKM2) and direct quantification by a partial dialysate collection method (PDC). Urea generation rate (G) was also found from a 1-week collection of dialysate and urine (OWC). Nine children aged 2-18 years and weighing 10.6-39.9 kg were examined over 1 week (25 treatments). UKM3 and UKM2 gave almost identical results, but deviated from PDC and OWC. The two indirect methods overestimated G by 24% and 18%. However, the correlations between the results were very high for all variables and all methods (r > or = 0.96). Repeating UKM3 and UKM2 mid-week for 5 consecutive weeks, the following coefficients of variation were found: for the normalised whole body urea clearance (Kt/V) 10% and 11%, respectively; for normalised protein catabolic rate 17% and 14%. It is concluded that all tested methods can be used, but each method requires its own reference interval. Results of UKM seem to vary somewhat more than in adults. This should be considered when assessing children by such methods.

Glucose-charged dialysate for children on hemodialysis: acute dialytic changes

“…Although serum potassium was not significantly increased at the beginning of the dialysis session (Table 1), clinical symptoms of hypokalemia or profound hypokalemia were not observed at the end of the 40 dialysis sessions. These results suggest that the usual dialysate prescribed for children containing 2 mmol/l potassium [2,6] should be reduced for many patients, allowing an improvement of dialytic potassium removal.…”

“…The dialysis session duration was 3 h: dialysates contained bicarbonate (35 mmol/l) and were potassium free (0 mmol/l). The prescribed dialysis dose was kept constant over the study period, adjusted to an equilibrated KT/V of 1.3 [6].…”

“…Blood samples were taken from the arterial blood access line Pediatr Nephrol (1998) 12: 60 ± 62 Ó IPNA 1998 prior to dialysis (t0), 45 min after initiation of the session (t45), at the end of the 3-h session (t180), i.e., after 3 min of low blood flow, 50 ml/ min [6], and during the so-called post-dialytic rebound period, at 30 min and 60 min postdialysis (t180+30, t180+60). During this postdialytic period, dialysate flow was stopped and extracorporeal circulation was maintained at a low blood flow, i.e., 50 ml/min.…”

Comparing a urea kinetic monitor with Daugirdas formula and dietary records in children

“…The best agreement was reached when a postdialysis blood sample was taken 2 min post blood pump rate reduction and a correction factor was applied to give double-pool eKt/V [11]. In children, different results from formal UKM with direct quantification has led to the conclusion that Kt/V should be interpreted according to the method used [3]. No studies have compared the result of the DF with the OLM in children.…”

“…Recently, guidelines for minimal Kt/V(urea) for adults have been proposed based on several studies linking low Kt/V(urea) to high morbidity and mortality [2]. Although dialysis prescription guidelines for children are only based on opinion and not on experimental data, UKM has been applied in children [3][4][5].…”