Key messages? More patients develop AKI outside the ICU and present with it rather than developing AKI while in ICU.? Using oliguria in isolation as a trigger for intervention in ICU might lead to some patients receiving unnecessary Lapatinib order intervention and other patients not receiving potentially helpful intervention.? Oliguria is relatively frequent in ICU patients and most episodes are not followed by AKI.? Oliguria has only a fair predictive ability for subsequent AKI and lacks clinical utility as a test at the observed frequencies of AKI in the ICU.? Oliguria accompanied by hemodynamic compromise or increasing vasopressor dose may represent a clinically useful trigger for other early biomarkers of renal injury with the goal of achieving a more accurate and timely identification of patients at risk of AKI.

AbbreviationsAKI: acute kidney Injury; AKI-Cr: acute kidney injury defined by changes in serum creatinine; AKIN: Acute Kidney Injury Network; AUC: area under the curve; CI: confidence interval; GFR: glomerular filtration rate; IQR: interquartile range; RIFLE: Risk Injury Failure Loss End stage; RIFLE-I: RIFLE-Injury: RIFLE I[Cr]: RIFLE-Injury by serum creatinine criteria; ROC: receiver-operator characteristic; SAPS II: Simplified Acute Physiology Score II; sCr: serum creatinine; SIRS: systemic inflammatory response syndrome.Competing interestsThe authors declare that they have no competing interests.Authors’ contributionsJRP participated in study design, collected data, prepared data, performed statistical analysis and wrote the paper. YL and EL participated in study design and collected data.

SM collected data and was the center organiser (Edmonton). ME collected data and was the center organiser (Okayama). MH and AH-F collected data and were center organisers (Berlin). JK was the center organiser (Pittsburgh). CR and DC collected data and were center organisers (Vicenza). KT collected data and SU was center organiser (Jikei). RB conceived the study, coordinated study Brefeldin_A centers, participated in study design, and edited the final manuscript. All authors read and approved the final manuscript.AcknowledgementsSource of funding Austin ICU Research Fund. We are grateful to Dr Kenji Tsutsui, (Intensive Care Unit, Department of Anesthesiology, Jikei University School of Medicine, Tokyo, Japan) and Drs Aditya Uppalapati & Neeta Kannan, (UPMC McKeesport, McKeesport, PA) for their assistance in data collection for this study. MH is a Fellow of the Alexander von Humboldt-Foundation, Bonn, Germany and AHF is a Fellow of the Jackst?dt-Foundation, Essen, Germany, both non-profit organizations.