ESPN 50th Annual Meeting

ESPN 2017


 
DEFINING OPTIMAL WEIGHT IN CHILDREN WITH CHRONIC KIDNEY DISEASE AND ON DIALYSIS: A COMPARISON OF TECHNIQUES
CAROLINE SY ENG 1 DEVINA BHOWRUTH 3 MARK MAYES 2 LYNSEY STRONACH 2 AMY BARBER 2 JOHN DEANFIELD 3 LESLEY REES 2 RUKSHANA C SHROFF 2

1- PAEDIATRIC NEPHROLOGY UNIT, TUANKU JA’AFAR HOSPITAL, SEREMBAN, MALAYSIA
2- DEPARTMENT OF PAEDIATRIC NEPHROLOGY, GREAT ORMOND STREET HOSPITAL FOR CHILDREN, LONDON, UNITED KINGDOM
3- UCL INSTITUTE OF CHILD HEALTH, VASCULAR PHYSIOLOGY, LONDON, UNITED KINGDOM
 
Introduction:

Fluid balance is pivotal in the management of children with chronic kidney disease (CKD) and on dialysis. Although many techniques are available to assess fluid status, there are few studies in children.

Material and methods:

We performed a longitudinal study in 30 CKD children and 13 age-matched healthy controls (71 measurements) to determine a correlation between optimal weight by bioimpedance spectroscopy (Wt-BIS) and clinical assessment (Wt-CA). The accuracy of Wt-BIS (relative overhydration [Rel OH]) was compared against indicators of fluid status such as peripheral blood pressure, central blood pressure, N terminal pro-brain natriuretic peptide (NT-proBNP) levels and cardiovascular end-points namely pulse wave velocity (PWV) Z-score for age, left ventricular hypertrophy end diastolic distance (LVEDd) and left ventricular mass index (LVMI).

Results:

There was poor agreement between Wt-CA and Wt-BIS among children on dialysis when compared to CKD5 or control subjects (p=0.01). We developed a modified chart to plot Rel OH against systolic blood pressure (SBP) Z- score for the appropriate representation of volume status and blood pressure in children. A quarter showed SBP above 90th percentile but not with concurrent overhydration. Rel OH correlated with peripheral pulse pressure (p=0.03; R=0.3) , higher NT-proBNP (p=0.02; R=0.33) and LVEDd (p=0.05;R=0.38). Central aortic mean and pulse pressure did not correlate with Rel OH but significantly associated with LVEDd. (p=0.03;R=0.47 and p=0.01;R=0.50 respectively). Systolic BP correlated with PWV Z-score (p=0.04). 40% of children on HD and 30% on PD had increased LVMI.

Conclusions:

We report a marked discrepancy between BP and hydration status in children on dialysis, suggesting that an objective method for the assessment of hydration status of children on dialysis is necessary.