• Oliguria indicates a reduction in glomerular filtration rate or a mechanical obstruction to urine flow.
• Prerenal cause of oliguria means decreased blood flow to kidneys; renal cause means kidneys not filtering properly; postrenal cause indicates mechanical obstruction.

Clinical Findings

GI/GU: Urine output <500 mL in 24 hr or <30 mL/hr for more than 2 hours.

Possible Causes: Renal hypoperfusion (hypovolemia, congestive heart failure, sepsis, blood loss); renal arterial disease; acute glomerulonephritis; acute tubular necrosis; tubular, ureteral, or urethral obstruction; drugs (aminoglycosides, radiocontrast medium).

Collaborative Management

• Monitor BP, HR, capillary refill time, mental status.
• Palpate bladder; if distended, check urinary drainage system for kinks or proper placement.
• If distended but no urinary drainage system is in place, help Pt use commode. Note amount of urine voided, and check for residual urine with bladder scan.
• If bladder not distended, assess for decreased renal perfusion or renal injury.
• Assess BP with Pt sitting and standing (or lying flat and sitting up); note orthostasis.
• Assess HR, I&O for past 48 hr, baseline and current renal function tests (BUN/creatinine), and current electrolyte levels.
• Monitor for low urine output or residual urine >100 mL.
• Assess for CHF (JVD, peripheral edema, dyspnea, and rales), which can cause decreased renal blood flow.
• Assess for potential causes of acute renal failure such as recent history of blood loss or dehydration, kidney injury, fever/possible sepsis, ingestion of nephrotoxic substances such antibiotics, ibuprofen, ACE inhibitors, contrast, or poisons.
• Establish IV access and administer IVF as ordered.
• Monitor I&O and assess for fluid overload.
• Insert urinary catheter and monitor hourly urine output.
• Obtain urine samples for analysis, culture, other studies.
• Monitor BUN/creatinine, chemistries, CBC.
• Administer diuretics as ordered.
• Transfer Pt to ICU if invasive monitoring is required.