Acute Renal Failure in ICU

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Acute Renal Failure in ICU

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Definition of ARF

• Serum creatinine (Scr), absolutely increase of
  0.5-1.0 mg/dl, a relative increase of 25-100
  over 24 hr
• Normal 0.6-1.5 mg/dl
• Mortality 30-50

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Manifestations

• Accumulation of nitrogenous waste BUN/Cr
• Oliguria U/O lt 400-500 ml/day, may or may not
  present

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Risk Factors for AKD

• Hypovolemia
• Hypotension
• Sepsis
• Frequently as part of multiple organ failure
• Pre-existing renal, hepatic, or cardiac
  dysfunction
• Diabetes mellitus
• Exposure to nephrotoxins
• Aminoglycosides, amphotericin, immunosuppressive
  agents, nonsteroidal anti-inflammatory drugs,
  angiotensin converting enzyme inhibitors,
  intravenous contrast media
• Two or more risk factors are usually present.

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Sepsis

• ARF19 in sepsis, 23 in severe sepsis, 51 in
  septic shock
• Mortality 74.5
• Hypoperfusion and compromised blood flow ?ARF
• Early goal-directed therapy for low BP,
  intravascular volume, ScvO2, decrease mortality
• Daily dialysis shorten duration of ARF

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Hepatorenal syndrome

• Profound renal vasoconstriction
• Type 1 rapid and profound deterioration,
  extremely high mortality
• Type 2 insidious onset
• Therapy mesenteric vasoconstrictors (midorine,
  octreotide, terlipressin), NAC
• Transjugular intrahepatic portosystemic shunt
  (TIPS)
• Liver transplantation

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Types of Acute Kidney Dysfunction

• Pre-renal (40 - 80)
• renal artery disease
• systemic hypotension
• Dehydration
• Intra-renal (10 - 50)
• acute tubular necrosis
• interstitial nephritis
• Post-renal (lt 10)
• obstruction

Significant overlap
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Diagnosis
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Management of Radiocontrast nephropathy

• Hydration NaHCO3 more effective than NaCl
• N-Acetylcysteine (NAC) antioxidant
• Diuretics
• Vasodilators Fenoldopam
• Dialysis

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Prevention of AKDGoals of therapy are to prevent
AKD or need for RRT

• Effective
• Hydration
• Prevent hypotension
• Avoid nephrotoxins
• Unknown
• N-acetylcysteine
• Sodium Bicarbonate
• Prophylactic Hemofiltration

• Ineffective/harmful
• Diuretics
• Dopamine
• Other renal vasoactive drugs
• DA-1 agonists
• PDE inhibitors
• Ca blockers
• Adenosine antagonists
• Natriuretic peptides

Kellum JA, Leblanc M, Venkatraman, R. Clinical
Evidence. 2004111094-118.
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Risks of Low-dose Dopamine

• Bowel mucosal ischemia
• Pro-arrhythmic
• Hypo-pituitarism (inhibition of TSH release from
  the pituitary)
• Immune suppression (inhibition of T-cell
  lymphocyte function)
• Bad medicine

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Treatment of AKDGoals of therapy are to prevent
death, reduce complications, hasten/permit renal
recovery

• Effective
• Hemodialysis
• Biocompatible membranes
• More dialysis
• Unknown
• CRRT vs. IHD
• Earlier dialysis

• Ineffective/harmful
• Diuretics
• Dopamine

Diuretics are never a treatment for oliguria
but are sometimes required for management of
volume overload.
Kellum JA, Leblanc M, Venkatraman, R. Clinical
Evidence. 2004 111094-118.
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Treatment Diuretics

• Diuretics Effects on outcome (large
  observational studies)
• 4-center, retrospective analysis of patients
  referred for nephrology consults (1989 - 1995 n
  552)
• With adjustments for co-variates and propensity
  score, diuretic use was associated with
• Significantly increased risk of death or
  non-recovery of renal function (odds ratio 1.77
  95 CI 1.14 - 2.76)
• Mehta et al. JAMA. 20022882547-53.
• 52-center, prospective inception cohort of ICU
  patients (n 1743)
• No differences in mortality, or renal recovery,
  even after adjustment for the same co-variates
  and propensity score
• Odds ratio 1.22 (p 0.15)
• However, no benefit associated with diuretics
  either!
• Uchino et al. Crit Care Med. 2004321669 77.

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Nephrotoxins

• Aminoglycosides once-daily dosing, used lt 5
  days, decrease toxicity
• Amphotericin B 30 toxicity
• Acyclovir crystal nephropathy (15-45),
  intravascular volume replacement, increasing
  urinary flow, slow infusion

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Indications for acute dialysis (AEIOU)

• Acidosis
• Electrolytes hyperkalemia
• Intoxication
• Overload (pulmonary edema)
• Uremia (altered mental status, seizures,
  pericarditis)

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Renal replacement therapy

• Peritoneal dialysis
• Hemodialysis
• Continuous renal replacement therapy (for
  hemodynamic unstable patients)

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Management of the complications of ARF

• Volume overload
• Hyponatremia
• Metabolic acidosis
• Hyperkalemia
• Hypermagnesemia
• Hyperphosphatemia
• Anemia

• Encephalopathy
• Decreased drug elimination
• Uremic pericarditis
• Bleeding abnormalities
• Infectious complication
• Nutritional support

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Conclusions/Recommendations

• For Treatment of AKD in the ICU
• Avoid further injury from nephrotoxins,
  hypotension, and dehydration.
• - Grades B - D for various options
• Dont use dopamine or other vasoactive drugs.
• - Grade A
• Avoid diuretics.
• - Grade D
• Use biocompatable membranes.
• - Avoid cuprophane (Grade A -)
• - Avoid all cellulosic membranes (Grade C)
• Use 35 ml/kg/min for CRRT and possibly daily
  dialysis for IRRT.
• - Grade B
• Use CRRT?
• - Grade D

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Case 1

• 53 y/o male, poorly controlled H/T, fever and
  cough for 2 days, CXR RLL infiltrate, BP 88/54
• Cr 1.5 mg/dl, BUN 42
• U/O 20-30 ml/hr
• After fluid challenge, BP 110/60

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Case 1

• U/O lt 0.5 ml/kg/hr
• UCr 50 mg/dL, FeNa 0.5, prerenal disease
• BUN/Cr 40/1.8, BUN/Cr gt20
• BP 90/55
• Lactate 2.7, SvO2 72, CVP 14
• Levophed infusion, activated protein C

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Case 1

• Next day, Cr 2, BP improves
• Complete recovery

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Case 2

• 64 y/o female, H/T, TVD, EF 20, 80 kg
• Undergo CABG
• Postop U/O 30-40 ml/hr, Cr 1.5 ? 2.0 mg/dl,
• C.I. 2.2, on epinephrine and dobutamine infusion
• Diagnosis ATN

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Case 2

• Next day, Cr 3.0, BUN 65, U/O 300 ml/day, I/O
  11L, 90 kg, edema
• Lasix no response, Cr 4.0, CVVH
• Next 5 days, 8L fluids removed, cardiac function
  improved, intermittent HD
• 1 week later, renal function improved
• 1 month later, Cr normal