[Assessment of total body water of patients on hemodialysis with urea kinetic model].
OBJECTIVE
To propose a method to evaluate the total body water (TBW) of patients on hemodialysis with urea kinetic model (UKM), and compare it with body surface bio-impedance spectrum (BIS) analysis.


METHODS
We enrolled 24 adult patients with end stage renal disease (ESRD) without hyper-catabolism in our dialysis center. All of them had been on hemodialysis for more than 3 months. TBW was measured with BIS analysis immediately before and after dialysis session, and one hour after hemodialysis session. Spent dialysate was collected; blood samples were taken before and one hour after hemodialysis session, TBW before hemodialysis session were calculated by UKM.


RESULTS
Patients were 6 men and 18 women, the average age was (51.2+/-13.5) years and the average time on dialysis was (33.2+/-36.7) months. Causes of ESRD included chronic glomerulonephritis (8 patients), diabetic nephropathy (1 patients), hypertensive renal damage (1 patients), interstitial nephritis(two patients), chronic pyelonephritis (two patients). The average ultrafiltration volume was (2.7+/-1.0) L (0.5-4.4 L) . Plasma urea concentrations were (23.06+/-5.76) mmol/L and (8.15+/-2.06) mmol/L before and one hour after hemodialysis session, respectively. There was no significant difference between TBW measured immediately after and one hour after hemodialysis session with BIS analysis [(29.9+/-8.8) L and (29.8+/-8.6) L, respectively; average difference was (0.1+/-0.9)L, P=0.70]. These two measurements correlated very well (Pearson r=0.99, P<0.05). There was no significant difference between UKM and BIS analysis [(31.4+/-7.3) L and (31.3+/-8.6) L, respectively; average difference was (0.2+/-4.5) L, P=0.87]. Results of these two methods correlated very well (Pearson r=0.86, r(2)=0.73,P< 0.05).


CONCLUSIONS
TBW measured with UKM in patients on hemodialysis provides theoretic basis for fluid status evaluation and dry body weight assessment.
Department of Nephrology, Peking University First Hospital, Beijing 100034, China. zuoli@medmail.com.cn
Li
L
Zuo
Mei
M
Wang
Hong
H
Wei
Jin-xia
JX
Peng
Li-li
LL
Feng
D000328:Adult; D000368:Aged; D001834:Body Water / Q000378:metabolism*; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000628:therapy* / Q000652:urine; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D006435:Renal Dialysis; D014563:Urodynamics