Physicochemical Analysis of Blood and Urine in the Course of Acute Kidney Injury in Critically Ill Patients: a Prospective, Observational Study

Overview

Journal BMC Anesthesiol

Publisher Biomed Central

Specialty Anesthesiology

Date 2013 Oct 12

PMID 24112801

Citations 14

Authors

Alexandre Toledo Maciel

Marcelo Park

Etienne Macedo

Affiliations

Soon will be listed here.

Abstract

Background: Sequential physicochemical alterations in blood and urine in the course of acute kidney injury (AKI) development have not been previously described. We aimed to describe these alterations in parallel to traditional renal and acid-base parameters.

Methods: One hundred and sixty eight consecutive critically ill patients with no previous kidney disease, who had an indwelling urinary catheter at ICU admission and who remained with the catheter for at least two days without dialysis were included. A sample of blood and spot urine were collected simultaneously, once daily, until catheter removal or dialysis requirement. Traditional acid-base and renal parameters were sequentially evaluated in parallel to blood and urinary physicochemical parameters. Patients were classified during this period as having or not AKI and, for patients with AKI, duration (transient or persistent) and severity (creatinine-based AKIN stage) were evaluated.

Results: One hundred and thirteen patients (67.3%) had AKI: 92 at ICU admission and 21 during the observation period. AKI development was characterized in blood by increased values of phosphate and unmeasured anions (SIG), decreased albumin, and in urine by decreased values of sodium (NaU), chloride (ClU) as well as high urinary strong ion difference (SIDu). These alterations began to occur before AKI diagnosis, and they reverted in transient AKI but remained in persistent AKI. NaU, ClU and albumin decreased, and phosphate, SIG and SIDu increased with AKI severity progression. NaU and ClU values increased again when AKIN stage 3 was reached.

Conclusions: Simultaneous physicochemical analysis of blood and urine revealed standardized alterations that characterize AKI development in critically ill patients. These alterations paralleled AKI duration and severity. Future studies should consider including sequential evaluation of urine biochemistry as part of the armamentarium for AKI diagnosis and management.

Citing Articles

Introducing the "urine biochemical approach": an alternative tool for improving acute kidney injury monitoring in critically ill patients.

Maciel A Front Nephrol. 2025; 5:1525551.

PMID: 40046268 PMC: 11879783. DOI: 10.3389/fneph.2025.1525551.

Optimizing Postoperative Acute Kidney Injury Monitoring Using a Urine Biochemical Approach-Time to Bring More Dynamism to Serum Creatinine Evaluation!.

Maciel A Indian J Crit Care Med. 2024; 28(8):729-733.

PMID: 39239174 PMC: 11372670. DOI: 10.5005/jp-journals-10071-24771.

Low urinary sodium-to-potassium ratio in the early phase following single-unit cord blood transplantation is a predictive factor for poor non-relapse mortality in adults.

Takano K, Monna-Oiwa M, Isobe M, Kato S, Takahashi S, Nannya Y Sci Rep. 2024; 14(1):1413.

PMID: 38228718 PMC: 10791692. DOI: 10.1038/s41598-024-51748-7.

Urinary sodium excretion is low prior to acute kidney injury in patients in the intensive care unit.

de Morais D, Sanches T, Santinho M, Yada E, Segura G, Lowe D Front Nephrol. 2023; 2:929743.

PMID: 37675036 PMC: 10479577. DOI: 10.3389/fneph.2022.929743.

Urine biochemistry assessment in the sequential evaluation of renal function: Time to think outside the box.

Maciel A, Vitorio D, Osawa E Front Med (Lausanne). 2022; 9:912877.

PMID: 35957852 PMC: 9360530. DOI: 10.3389/fmed.2022.912877.

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