PMID- 10469385
OWN - NLM
STAT- MEDLINE
DCOM- 19991021
LR  - 20131121
IS  - 0085-2538 (Print)
IS  - 0085-2538 (Linking)
VI  - 56
IP  - 3
DP  - 1999 Sep
TI  - Quest for postdialysis urea rebound-equilibrated Kt/V with only intradialytic 
      urea samples.
PG  - 1149-53
AB  - BACKGROUND: Postdialysis urea rebound (PDUR) is a cause of Kt/V overestimation 
      when it is calculated from predialysis and the immediate postdialysis blood urea 
      collections. Measuring PDUR requires a 30- or 60-minute postdialysis sampling, 
      which is inconvenient. Several methods had been devised for a reasonable approach 
      to determine PDUR-equilibrated Kt/V in short dialysis without the need for a 
      delayed sample. The aim of our study was to compare these different Kt/V methods 
      during the longer eight-hour hemodialysis sessions, and to determine the optimum 
      intradialytic urea sample time that fits best with PDUR. METHODS: The study 
      included 21 patients (mean age 71.9 years) who were hemodialyzed for 60+/-60 
      months at three times eight hours weekly, using bicarbonate dialysate and 
      cellulosic membranes. Blood urea samples were obtained at onset, and then at 17, 
      33, 50, 66, 75, 80, 85, and 100% of the dialysis session times, after 30 seconds 
      of low flow, and then at 60-minutes postdialysis. All patients had a meal during 
      dialysis. We compared four different formulas of Kt/V [(a) Kt/V-Smye with a 33% 
      dialysis time urea sample, (b) two-pool equilibrated eKt/V, (c) Kt/V-std 
      (Daugirdas-2) obtained with an immediate postdialytic sample, and (d) the 
      different intradialytic urea samples for Kt/V (50, 66, 75, 80, and 85% of 
      dialysis time)] with the equilibrated 60-minute PDUR Kt/V (Kt/V-r-60) formula as 
      the reference method. RESULTS: The mean PDUR was 17.2+/-9%, leading to an 
      overestimation of Kt/V-std by 12.2%. Kt/V-r-60 was 1.68+/-0.34. Kt/V-std was 
      1.88+/-0.36 (Delta = 12.2+/-4.8%, r = 0.8). eKt/V was 1.77+/-0.3 (Delta = 5+/-5%, 
      r = 0.96), and Kt/V-Smye was 1.79+/-0.47 (Delta = 5.2+/-14%, r = 0.9). The best 
      time for the intradialytic sampling was 80% (that is, at 6 hr and 24 min). The 
      Kt/V-80 was 1.64+/-0.3 and was best fitted with Kt/V-r-60 (Delta = -1.8+/-8%, r = 
      0.91). The mean intradialytic urea evolution showed a three-exponential rate, in 
      discrepancy with the two-exponential rate theoretical model. CONCLUSIONS: These 
      results confirm that a significant postdialysis rebound exists in an eight-hour 
      dialysis. An intradialytic urea sample taken at 80% of the total session time 
      permits an estimation of the 60-minute Kt/V-rebound without the necessity of 
      taking a delayed sample, with better accuracy than eKt/V or especially Kt/V-Smye. 
      This may be related to a particular urea kinetics curve on the longer dialysis 
      duration, which needs to be studied further.
FAU - Jean, G
AU  - Jean G
AD  - Centre de Rein Artificiel de Tassin, Tassin la Demi-Lune, France. 
      GJean14357@aol.com
FAU - Charra, B
AU  - Charra B
FAU - Chazot, C
AU  - Chazot C
FAU - Laurent, G
AU  - Laurent G
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - United States
TA  - Kidney Int
JT  - Kidney international
JID - 0323470
RN  - 8W8T17847W (Urea)
SB  - IM
MH  - Aged
MH  - Female
MH  - Humans
MH  - Kinetics
MH  - Male
MH  - Middle Aged
MH  - Models, Biological
MH  - *Renal Dialysis/statistics & numerical data
MH  - Urea/*blood
EDAT- 1999/09/01 00:00
MHDA- 1999/09/01 00:01
CRDT- 1999/09/01 00:00
PHST- 1999/09/01 00:00 [pubmed]
PHST- 1999/09/01 00:01 [medline]
PHST- 1999/09/01 00:00 [entrez]
AID - S0085-2538(15)46395-1 [pii]
AID - 10.1046/j.1523-1755.1999.00616.x [doi]
PST - ppublish
SO  - Kidney Int. 1999 Sep;56(3):1149-53. doi: 10.1046/j.1523-1755.1999.00616.x.