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. 2016 Feb 19:20:43.
doi: 10.1186/s13054-016-1225-5.

Daily urinary urea excretion to guide intermittent hemodialysis weaning in critically ill patients

Julien Aniort  1 , Ali Ait Hssain  2 , Bruno Pereira  3 , Elisabeth Coupez  4 , Pierre Antoine Pioche  5 , Christophe Leroy  6 , Anne Elisabeth Heng  7 , Bertrand Souweine  8   9 , Alexandre Lautrette  10   11
Affiliations

Daily urinary urea excretion to guide intermittent hemodialysis weaning in critically ill patients

Julien Aniort et al. Crit Care. .

Abstract

Background: There are no easily available markers of renal recovery to guide intermittent hemodialysis (IHD) weaning. The aim of this study was to identify markers for IHD weaning in critically ill patients with acute kidney injury (AKI).

Methods: We performed a retrospective single-center cohort study of patients treated with IHD for at least 7 days and four dialysis sessions for AKI between 2006 and 2011 in an intensive care unit (ICU) of a French university hospital. Blood and urinary markers were recorded on the day of the last IHD in the ICU for unweaned patients and 2 days after the last IHD for weaned patients. Factors associated with IHD weaning were identified by multiple logistic regression. The areas under the receiver operating characteristic curve (AUROC) and the characteristics of the best diagnostic thresholds were compared.

Results: Sixty-seven patients were analyzed, including thirty-seven IHD-weaned patients. Urine output [odds ratio (OR) 1.59, 95% confidence interval (CI) 1.20-2.10 (per ml/kg/24 h increase); P = 0.01] and urinary urea concentration [OR 1.29, 95% CI 1.01-1.64 (per 10 mmol/L increase); P = 0.04] were both associated with IHD weaning. The optimal diagnostic thresholds for IHD weaning were urine output greater than 8.5 ml/kg/24 h, urinary urea concentration greater than 148 mmol/L, and daily urea excretion greater than 1.35 mmol/kg/24 h, with accuracy of 82.1%, 76.1%, and 92.5% (P = 0.03), respectively. The AUROC of daily urinary urea excretion (0.96) was greater than the AUROC of urine output (0.86) or the AUROC of urinary urea concentration (0.83) (P < 0.001).

Conclusions: A daily urinary urea excretion greater than 1.35 mmol/kg/24 h was found to be the best marker for weaning ICU patients with AKI from IHD.

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Figures

Fig. 1
Fig. 1
Patient flowchart. AKI acute kidney injury, CRRT continuous renal replacement therapy, DFLST decision to forgo life-sustaining therapy, IHD intermittent hemodialysis, ICU intensive care unit, RRT renal replacement therapy, UO urine output
Fig. 2
Fig. 2
a Predictive ability for intermittent hemodialysis weaning. The area under the receiver operating characteristic curve values were 0.86 (0.79–0.94) for UO, 0.83 (0.74–0.92) for uUrea, and 0.96 (0.93–0.99) for eUrea. Thresholds with the highest accuracy are given for each variable. b Distribution of weaned and unweaned patients according to UO, uUrea, and eUrea. The blue curve corresponds to an eUrea of 1.35 mmol/kg/24 h and was obtained using the following equation: [UO (ml/kg/24 h)/1000] × uUrea (mmol/L) = 1.35 mmol/kg/24 h. eUrea daily urinary urea excretion, uUrea urinary urea concentration, UO urine output
See this image and copyright information in PMC

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