Oliguria or hypouresis is the low output of urine: specifically, more than 80 ml/day, but less than 400ml/day.
Beyond oliguria is anuria, which represents an absence of urine, clinically classified as below 80 or 100 ml/day.
The term oliguria is derived from oligo-meaning "small, little," + - uria, from the Greek word ouron, meaning "urine".
Definition
Oliguria is defined as a urine output that is less than 1 mL/kg/h in infants,
[ Free Full Text .] less than 0.5 mL/kg/h in children,
[ and less than 400 mL][ or 500 mL][ Merck manuals > Oliguria Last full review/revision March 2009 by Soumitra R. Eachempati] per 24h in adults - this equals 17 or 21 mL/hour. For example, in an adult weighing 70 kg it equals 0.24 or 0.3 mL/kg/h. Alternatively, however, the value of 0.5 mL/kg/h is commonly used to define oliguria in adults as well.[
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Diagnostic approach
Perform ultrasound examination of the kidney to rule out obstructive processes.
The mechanisms causing oliguria can be categorized globally in three different categories:
Postoperative oliguria
Patients usually have a decrease in urine output after a major operation that may be a normal physiological response to:
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fluid/ blood loss – decreased glomerular filtration rate secondary to hypovolemia and/or hypotension
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response of adrenal cortex to stress-increase in aldosterone (Na and water retention) and antidiuretic hormone (ADH) release
Babies
Oliguria, when defined as less than 1 mL/kg/h, in is not attributed to kidney failure.
See also
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Polyuria (excessive urine production)
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Anuria (absolute lack of urine output)
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Intra-abdominal hypertension (IAH) and Abdominal Compartment Syndrome (ACS)
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