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The Association Between Urine Output, Creatinine Elevation, and Death.
Milo Engoren1, Michael D Maile1, Michael Heung2
1Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan.
The Annals of Thoracic Surgery
|October 9, 2016
Summary
Reduced urine output after cardiac surgery is a sensitive indicator of acute kidney injury (AKI). Low urine output, even without creatinine elevation, independently predicts mortality, highlighting its clinical significance.
Area of Science:
- Nephrology
- Cardiovascular Surgery
- Critical Care Medicine
Background:
- Urine output criteria may detect acute kidney injury (AKI) earlier than serum creatinine.
- The link between urine output, creatinine rise, and mortality post-cardiac surgery requires further characterization.
Purpose of the Study:
- To determine the association between degrees of reduced urine output and subsequent creatinine elevation and death.
- To evaluate the predictive accuracy of urine output for AKI and mortality.
Main Methods:
- Retrospective cohort study of adult patients undergoing cardiac operations.
- AKI defined as creatinine increase >0.3 mg/dL or >50% from baseline by postoperative day 3.
- Analysis of urine output in relation to AKI development and mortality.
Main Results:
- 25% of patients (1,061/4,195) developed AKI.
- Lower urine output and longer duration of oliguria were associated with increased odds of AKI and death.
- Urine output showed moderate discrimination for predicting AKI (C-statistic = 0.637).
Conclusions:
- Urine output corrected for actual weight is recommended for simplicity in predicting AKI.
- Low urine output is independently associated with subsequent AKI and mortality.
- Oliguria (<0.2 mL·kg⁻¹·h⁻¹) predicts mortality even without creatinine-defined AKI.
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