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Fluid balance, change in serum creatinine and urine output as markers of acute kidney injury post cardiac surgery: an observational study Chau, Katrina; Schisler, Travis; Er, Lee; Jaswal, Dharmvir; Cheung, Christopher; Israel, Amanda; Bowering, John; Levin, A. (Adeera)

Abstract

Background: Acute kidney injury (AKI) is defined as oliguria or rise in serum creatinine but oliguria alone as a diagnostic criterion may over-diagnose AKI. Objectives: Given the association between fluid overload and AKI, we aimed to determine if positive fluid balance can complement the known parameters in assessing outcomes of AKI. Design: Prospective observational study. Setting: Teaching hospital in Vancouver, Canada. Patients: 111 consecutive patients undergoing elective cardiac surgery from January to April 2012. Measurements: Outcomes of cardiac surgery intensive care unit (CSICU) and hospital length of stay (LOS) in relation to fluid balance, urine output and serum creatinine. Methods: All fluid input and output was recorded for 72 hours post-operatively. Positive fluid balance was defined as >6.5 cc/kg. Daily serum creatinine and hourly urine output were recorded and patients were defined as having AKI according to the AKIN criteria. Results: Of the patients who were oliguric, those with fluid overload trended towards longer LOS than those without fluid overload [CSICU LOS: 62 and 39 hours (unadjusted p-value 0.02, adjusted p-value 0.58); hospital LOS: 13 and 9 days (unadjusted p-value: 0.05, adjusted p-value: 0.16)]. Patients with oliguria who were fluid overloaded had similar LOS to patients with overt AKI (change in serum creatinine ≥ 26.5 µmol/L), [CSICU LOS: 62 and 69 hours (adjusted p value: 0.32) and hospital LOS: 13 and 14 days (adjusted p value: 0.19)]. Patients with oliguria regardless of fluid balance had longer CSICU LOS (adjusted p value: 0.001) and patients who were fluid overloaded in the absence of AKI had longer hospital LOS (adjusted p value: 0.02). Limitations: Single centre, small sample, LOS as outcome. Conclusions: Oliguria and positive fluid balance is associated with a trend towards longer LOS as compared to oliguria alone. Fluid balance may therefore be a useful marker of AKI, in addition to urine output and serum creatinine.

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Title
Fluid balance, change in serum creatinine and urine output as markers of acute kidney injury post cardiac surgery: an observational study
Creator
Chau, Katrina; Schisler, Travis; Er, Lee; Jaswal, Dharmvir; Cheung, Christopher; Israel, Amanda; Bowering, John; Levin, A. (Adeera)
Publisher
BioMed Central
Date Issued
2014-09-02
Description
Background: Acute kidney injury (AKI) is defined as oliguria or rise in serum creatinine but oliguria alone as a diagnostic criterion may over-diagnose AKI. Objectives: Given the association between fluid overload and AKI, we aimed to determine if positive fluid balance can complement the known parameters in assessing outcomes of AKI. Design: Prospective observational study. Setting: Teaching hospital in Vancouver, Canada. Patients: 111 consecutive patients undergoing elective cardiac surgery from January to April 2012. Measurements: Outcomes of cardiac surgery intensive care unit (CSICU) and hospital length of stay (LOS) in relation to fluid balance, urine output and serum creatinine. Methods: All fluid input and output was recorded for 72 hours post-operatively. Positive fluid balance was defined as >6.5 cc/kg. Daily serum creatinine and hourly urine output were recorded and patients were defined as having AKI according to the AKIN criteria. Results: Of the patients who were oliguric, those with fluid overload trended towards longer LOS than those without fluid overload [CSICU LOS: 62 and 39 hours (unadjusted p-value 0.02, adjusted p-value 0.58); hospital LOS: 13 and 9 days (unadjusted p-value: 0.05, adjusted p-value: 0.16)]. Patients with oliguria who were fluid overloaded had similar LOS to patients with overt AKI (change in serum creatinine ≥ 26.5 µmol/L), [CSICU LOS: 62 and 69 hours (adjusted p value: 0.32) and hospital LOS: 13 and 14 days (adjusted p value: 0.19)]. Patients with oliguria regardless of fluid balance had longer CSICU LOS (adjusted p value: 0.001) and patients who were fluid overloaded in the absence of AKI had longer hospital LOS (adjusted p value: 0.02). Limitations: Single centre, small sample, LOS as outcome. Conclusions: Oliguria and positive fluid balance is associated with a trend towards longer LOS as compared to oliguria alone. Fluid balance may therefore be a useful marker of AKI, in addition to urine output and serum creatinine.
Subject
Acute kidney injury; Diagnosis; Fluid resuscitation; Cardiac surgery
Genre
Article
Type
Text
Language
eng
Date Available
2016-01-25
Provider
Vancouver : University of British Columbia Library
Rights
Attribution 4.0 International (CC BY 4.0)
DOI
10.14288/1.0223767
URI
http://hdl.handle.net/2429/56709
Affiliation
Anesthesiology, Pharmacology and Therapeutics, Department of; Medicine, Department of; Medicine, Faculty of; Other UBC
Citation
Canadian Journal of Kidney Health and Disease. 2014 Sep 02;1(1):19
Publisher DOI
10.1186/s40697-014-0019-4
Peer Review Status
Reviewed
Scholarly Level
Faculty
Copyright Holder
Chau et al.; licensee BioMed Central Ltd.
Rights URI
http://creativecommons.org/licenses/by/4.0/
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Attribution 4.0 International (CC BY 4.0)