From the Guidelines
Oliguria is defined as urine output less than 0.5 mL/kg/hour in adults, indicating potential kidney dysfunction, as stated in the most recent and highest quality study 1.
Definition and Management of Oliguria
The definition of oliguria is crucial for identifying potential kidney dysfunction. According to the study published in the Journal of the American College of Radiology in 2021 1, oliguria is defined as a urine output of less than 0.5 mL/kg/hour. This definition is essential for clinicians to identify patients at risk of acute kidney injury (AKI) and to initiate prompt management.
Causes and Assessment
The causes of oliguria can be multifactorial, including hypovolemia, renal disease, or urinary tract obstruction. Initial assessment should include vital signs, physical examination for volume status, and laboratory tests (BUN, creatinine, electrolytes) 1.
Management
For hypovolemic oliguria, prompt fluid resuscitation with isotonic crystalloids (normal saline or Ringer's lactate) at 500-1000 mL over 1-2 hours is recommended, followed by reassessment 1. If oliguria persists despite adequate volume restoration, a trial of diuretics may be appropriate, typically furosemide 20-40 mg IV, which can be increased to 80-160 mg if needed 1.
Monitoring and Advanced Interventions
Continuous monitoring of fluid balance, vital signs, and kidney function is essential. For patients not responding to initial management, more advanced interventions may be necessary, including nephrology consultation and consideration of renal replacement therapy if there are signs of fluid overload, severe electrolyte abnormalities, or uremia 1.
Prevention of Further Kidney Injury
Preventing further kidney injury by avoiding nephrotoxic medications, maintaining adequate blood pressure (mean arterial pressure >65 mmHg), and treating underlying conditions is crucial 1. Oliguria requires urgent attention as it may signal acute kidney injury, which can progress rapidly and significantly increase morbidity and mortality.
From the Research
Definition of Oliguria
- Oliguria is defined as a decreased urine output, typically less than 400 milliliters per 24 hours in adults 2, 3.
- It is a common complication in critically ill patients and can be caused by a variety of factors, including dehydration, kidney injury, and certain medications.
Management of Oliguria
- The management of oliguria depends on the underlying cause and may involve fluid resuscitation with crystalloids such as normal saline or lactated Ringer's solution 4, 3.
- The choice of fluid may depend on the patient's individual needs and the clinical context, with some studies suggesting that lactated Ringer's solution may be associated with improved outcomes in certain situations 3, 5.
- Other management strategies may include the use of diuretics, vasopressors, and other medications to support kidney function and blood pressure.
Fluid Resuscitation
- Fluid resuscitation is a critical component of the management of oliguria, and the choice of fluid can have important implications for patient outcomes 2, 4, 3.
- Normal saline and lactated Ringer's solution are both commonly used for fluid resuscitation, but they have different electrolyte compositions and may have different effects on kidney function and acid-base balance 2, 4, 3.
- Some studies have suggested that lactated Ringer's solution may be associated with improved outcomes in patients with sepsis-induced hypotension and acute pancreatitis 3, 5.