• DOI:10.1093/NDT/GFL541
• Corpus ID: 9320138

Urinary biochemistry in experimental septic acute renal failure.

@article{Langenberg2006UrinaryBI,
  title={Urinary biochemistry in experimental septic acute renal failure.},
  author={Christoph Langenberg and Li Wan and Sean M. Bagshaw and Moritoki Egi and Clive N. May and Rinaldo Bellomo},
  journal={Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association},
  year={2006},
  volume={21 12},
  pages={
          3389-97
        }
}

• C. Langenberg, L. Wan, +3 authors R. Bellomo
• Published 1 December 2006
• Medicine, Biology
• Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association

BACKGROUND
Several biochemical urine tests and derived indices are reported as useful in the diagnosis of acute renal failure (ARF) and its classification in prerenal (hypoperfusion) or intrarenal (acute tubular) necrosis. However, they have not been adequately studied in sepsis, the most frequent cause of ARF in ICU.

METHODS
In 10 female Merino ewes, we implanted flow probes around the pulmonary and renal arteries to measure cardiac output and renal blood flow (RBF) continuously. Cardiovascular variables were monitored and urine samples collected during a 48 h control period and one week later during a 48 h period of hyperdynamic sepsis induced by an infusion of live Escherichia coli.

RESULTS
Infusion of live E. coli induced systemic hyperdynamic sepsis with renal vasodilatation and increased RBF. Serum creatinine increased from 73.3 +/- 15.1 to 276.9 +/- 156.3 micromol/l (P < 0.05) and creatinine clearance decreased from 84.6 +/- 21.4 to 27.5 +/- 21.4 ml/min (P < 0.05). Urine sodium concentration (UNa) decreased significantly from 164.5 +/- 50.4 to 14.6 +/- 14.3 mmol/l, fractional excretion of sodium (FeNa) from 1.5 +/- 0.17 to 0.12 +/- 0.11%, fractional excretion of urea nitrogen (FeUn) from 62.7 +/- 9.5 to 11.5 +/- 15.4%, and urine osmolality from 724.8 +/- 277.1 mosmol/l to 329.0 +/- 52.1 mosmol/l. The u/p creatinine ratio did not change.

CONCLUSION
Sustained Gram-negative sepsis induced a hyperdynamic state and hyperaemic ARF. Despite increased renal perfusion, UNa, FeNa and FeUn decreased significantly. Our findings suggest that, in sepsis, these urinary biochemical changes are not reliable markers of renal hypoperfusion.