2. Definition of decreased urine output
(oliguria)
Questions to consider when first
presented with oliguria
Recognizing causes of oliguria
Focused review of history and physical
Management of oliguria
◦ Recognizing life threatening
complications
3. Oliguria = Urine output <400cc/day
(<20cc/hr)
◦ Another def: urine output <0.5ml/kg/hr
Anuria = no urine output
◦ Can signify complete mechanical
obstruction of bladder outlet or a blocked
Foley
4. Does the pt have a foley catheter?
YES NO
FLUSH FOLEY CATHETER
WITH 30-50CC NS
OBTAIN PVR (w/ US or cath
[will provide urine sample])
URINE OUTPUT IMPROVED? PVR ≥ 100? (≥ 50 in younger pts)
YESYES NO NO
FOLEY LIKELY
CLOGGED
WITH
SEDIMENT
PROCEDE
WITH
FURTHER
MANAGEMENT
START FOLEY
& PROCEDE W/
FURTHER
MANAGEMENT
PROCEED
WITH
FURTHER
MANAGEMENT
5. Consider the pathophysiology/causes of
decreased urine output. Three categories of
causes:
Prerenal:
◦ Volume depletion/dehydration/inadequate fluid
maintenance/Infection/sepsis
◦ Reduced cardiac output
ICU setting: mechanical ventilation can
also lead to low cardiac output
◦ Drugs
◦ Does the pt have liver cirrhosis
8. Review chart to look for clues that may elicit
etiology (see previous slide)
History (sepsis, CHF, tumors, renal failure…etc)
Meds: diuretics, ace,
aminoglycosides/vancomycin, iv contrast, NSAIDs
Old Labs: BUN/Cr (ratio); urine lytes; blood
cultures; vanco trough levels
9. Obtain new vitals, including orthostatics
Look for:
◦ Jaundice
◦ Crackles, pleural effusion
◦ JVP, CVP if pt has central line
Especially useful in ICU for pt with central line: for
example a CVP of 2 can be good evidence for
hypovolemia
◦ Palpate Kidneys and Bladder
◦ Prostate/Cervical Exam
◦ Rash
10. -Vitals: orthostatics can signify hypovolemia;
Tachycardia - hypovolemia/infection; Fever –
infection/UTI
-Jaundice (liver cirrhosis – hepatorenal)
-Crackles, pleural effusion (CHF, volume
overload)
-JVP, CVP if pt has central line (will help assess
fluid status)
-Palpate Kidneys and Bladder (hydronephrosis,
enlargement in obstruction/post-renal)
-Prostate/Cervical Exam (again for
obstruction/post-renal)
-Rash (AIN, embolic renal failure)
11. If not already done, order basic
electrolytes, CMP (monitor changes in
Cr/GFR), and urine studies (U/A, Na,
BUN, Cr), to further help classify etiology
Adjust/replace/discontinue and
nephrotoxic agents. Also, renally dose the
non-toxic meds
12. -Urine studies: U/A – look for proteinuria,
hematuria, eosinophilia, evidence of
rhabdomyolysis,
RBC/WBC/Granular/Pigmented/epithelial
casts…etc.
-Urine lytes: e.g. urine sodium <20
(prerenal), FENa: <1? Vs >2%/ FeUrea: <35?
-Note: On CMP look for presence and degree
of renal insufficiency.
Also look for possible complications (especially one that can
be life threatening) of renal insufficiency (e.g. hyperkalemia,
metabolic acidosis…etc).
13. Early recognition and intervention of potential
life threatening complications (direct or indirect
causes – e.g. renal failure) is essential
◦ Hyperkalemia: obtain EKG if elevated
◦ CHF/Pulmonary Edema
◦ Metabolic acidosis; Uremia (encephalopathy,
pericarditis)
◦ Advanced complications of above may require dialysis
14. Prerenal:
◦ Treat underlying cause
◦ If volume depleted (see physical exam): NS
boluses (500-1000ml fluid challenges) –
can repeat until response (but need to
monitor for fluid overload)
◦ Avoid/be very cautious about giving
lasix (again investigation of underlying
cause should drive this decision).
15. Postrenal:
◦ Treat underlying cause
◦ Initiate Foley catheter (clear/flush
catheter if already in place)
◦ Obtain Renal Ultrasound to assess for
upper urinary tract problems
Intrarenal:
◦ Treat underlying causes (e.g. sever
sepsis/shock)
16. Verify urine output w/ definition of oliguria in
mind.
If pt has a Foley catheter, flushing Foley is a
good initial step. If no Foley, a PVR can help
assess the need for Foley.
A focused chart review along with a focused
history and physical can help clue in on the
pathophysiology including pre-
renal/intrinsic/post-renal causes.
Recognizing life threatening complications (e.g.
hyperkalemia, acidosis, uremia) is an essential
component of acute/early management.
17. Decreased urine output does NOT mean
lasix deficiency. Administering lasix may
actually exacerbate problem. However very
specific causes may require lasix.
Fluid boluse(s) is a good initial step (be very
cautious in CHF).
Ultimately, regardless of pathophysiology,
treating underlying cause is key for both
acute and long term management.