Oliguria in critically ill patients: a narrative review

Area of Science:

• Critical Care Medicine
• Nephrology
• Clinical Pathophysiology

Background:

• Oliguria, defined as reduced urine output (UO), is common in critically ill patients.
• The clinical significance of transient oliguria (<0.5 ml/kg/h for ≥6 h) is debated, especially when serum creatinine remains normal.
• Pathophysiological variability in oliguria suggests differing clinical implications and reversibility.

Purpose of the Study:

• To investigate the clinical relevance of oliguria in critically ill individuals.
• To propose a diagnostic and therapeutic management pathway for oliguric critically ill patients.

Main Methods:

• Review of existing literature on oliguria in critical care.
• Analysis of clinical data to assess the impact of oliguria on mortality.
• Development of a proposed clinical pathway based on evidence and expert consensus.

Main Results:

• Isolated oliguria, even without increased serum creatinine, is linked to increased mortality.
• Underlying causes of oliguria can influence its reversibility and clinical importance.
• A structured approach to managing oliguria is necessary for improved patient outcomes.

Conclusions:

• Oliguria in critically ill patients warrants careful evaluation due to its association with adverse outcomes.
• Differentiating reversible causes from more severe conditions is crucial for effective management.
• The proposed clinical pathway aims to standardize the diagnostic and therapeutic response to oliguria in critical care settings.