Do we know what we mean?
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There are more than 35 definitions of AKI
(formerly acute renal failure) in literature!
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Mehta R, Chertow G: Acute renal failure definitions and classification: Time for change? Journal of American
Society of Nephrology 2003; 14:2178-2187.
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RIFLE classification
AKIN classification
Bellomo R, Ronco C, Kellum J, et al.: Acute renal failure-definition, outcome measures, animal models, fluid
therapy and information technology needs: The Second International Consensus Conference of the Acute Dialysis
Initiative (ADQI) Group. Critical Care 2004; 8:R204-R212.
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Modification of the RIFLE classification by Acute
Kidney Injury Network (AKIN).
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Recognizes that small changes in serum
creatinine (>0.3 mg/dl) adversely impact clinical
outcome.
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Uses serum creatinine, urinary output and time.
Coca S, Peixoto A, Garg A, et al.: The prognostic importance of a small acute decrement in kidney function in
hospitalized patients: a systematic review and meta-analysis. American Journal of Kidney Diseases 2007; 50:712720.
AKIN Serum Creatinine
stage Criteria
Urinary Output Time
Criteria
1
 Cr ≥ 0.3 mg/dL or 
≥ 150-200% from
baseline
< 0.5
mL/kg/hr
> 6 hrs
2
 Cr to > 200-300%
from baseline
< 0.5
mL/kg/hr
> 12 hrs
3
Cr to > 300% from
baseline or Cr ≥
4mg/dL with an acute
rise of at least 0.5
mg/dL
< 0.5
mL/kg/hr
or anuria
X 24 hrs
X 12 hrs
*Patients needing RRT are classified stage 3 despite the stage they were before starting RRT
Mehta R, Kellum J, Shah S, et al.: Acute kidney Injury Network: Report of an Initiative to improve outcomes in
Acute Kidney Injury. Critical Care 2007; 11: R31.
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AKI is an abrupt (within 48 hrs) reduction in
kidney function currently defined as an
absolute increase in serum creatinine of ≥
0.3 mg/dL (≥ 26.4 μmol/L), a percentage
increase in serum creatinine of ≥ 50%, or a
reduction in urine output (documented
oliguria of < 0.5 mL/kg/hr for > 6hrs.
Mehta R, Kellum J, Shah S, et al.: Acute kidney Injury Network: Report of an Initiative to improve outcomes in
Acute Kidney Injury. Critical Care 2007; 11: R31.
AKI occurs in
 ≈ 7% of hospitalized patients.
 36 – 67% of critically ill patients (depending
on the definition).
 5-6% of ICU patients with AKI require RRT.
Nash K, Hafeez A, Hou S: Hospital-acquired renal insufficiency. American Journal of Kidney Diseases 2002;
39:930-936.
Hoste E, Clermont G, Kersten A, et al.: RIFLE criteria for acute kidney injury are associated with hospital mortality
in critically ill patients: A cohort analysis. Critical Care 2006; 10:R73.
Osterman M, Chang R: Acute Kidney Injury in the Intensive Care Unit according to RIFLE. Critical Care Medicine
2007; 35:1837-1843.
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Mortality increases proportionately with
increasing severity of AKI (using RIFLE).
AKI requiring RRT is an independent risk
factor for in-hospital mortality.
Mortality in pts with AKI requiring RRT 5070%.
Even small changes in serum creatinine are
associated with increased mortality.
Hoste E, Clermont G, Kersten A, et al.: RIFLE criteria for acute kidney injury are associated with hospital mortality in critically ill patients:
A cohort analysis. Critical Care 2006; 10:R73.
Chertow G, Levy E, Hammermeister K, et al.: Independent association between acute renal failure and mortality following cardiac
surgery. American Journal of Medicine 1998; 104:343-348.
Uchino S, Kellum J, Bellomo R, et al.: Acute renal failure in critically ill patients: A multinational, multicenter study. JAMA 2005; 294:813818.
Coca S, Peixoto A, Garg A, et al.: The prognostic importance of a small acute decrement in kidney function in hospitalized patients: a
systematic review and meta-analysis. American Journal of Kidney Diseases 2007; 50:712-720.
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Serum Creatinine
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Urine Output
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Time
Dennen P, Douglas I, Anderson R,: Acute Kidney Injury in the Intensive Care Unit: An update and primer for the
Intensivist. Critical Care Medicine 2010; 38:261-275.
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Sepsis
Major surgery
Low cardiac output
Hypovolemia
Medications (20%)
Uchino S, Kellum J, Bellomo R, et al.: Acute renal failure in critically ill patients: A multinational, multicenter study.
JAMA 2005; 294:813-818.
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Hepatorenal syndrome
Trauma
Cardiopulmonary bypass
Abdominal compartment syndrome
Rhabdomyolysis
Obstruction
Dennen P, Douglas I, Anderson R,: Acute Kidney Injury in the Intensive Care Unit: An update and primer for the
Intensivist. Critical Care Medicine 2010; 38:261-275.
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NSAIDs
Aminoglycosides
Amphotericin
Penicillins
Acyclovir
Cytotoxics
Radiocontrast dye
Dennen P, Douglas I, Anderson R,: Acute Kidney Injury in the Intensive Care Unit: An update and primer for the
Intensivist. Critical Care Medicine 2010; 38:261-275.
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Recognition of underlying risk factors
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Diabetes
CKD
Age
HTN
Cardiac/liver dysfunction
Maintenance of renal perfusion
Avoidance of hyperglycemia
Avoidance of nephrotoxins
Dennen P, Douglas I, Anderson R,: Acute Kidney Injury in the Intensive Care Unit: An update and primer for the
Intensivist. Critical Care Medicine 2010; 38:261-275.
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Avoid use of intravenous contrast in high risk
patients if at all possible.
Use pre-procedure volume expansion using
isotonic saline (?bicarbonate).
NAC
Avoid concomitant use of nephrotoxic
medications if possible.
Use low volume low- or iso-osmolar contrast
Dennen P, Douglas I, Anderson R,: Acute Kidney Injury in the Intensive Care Unit: An update and primer for the
Intensivist. Critical Care Medicine 2010; 38:261-275.
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Intravenous albumin significantly reduces the
incidence of AKI and mortality in patients
with cirrhosis and SBP.
Albumin decreases the incidence of AKI after
large volume paracentesis.
Albumin and terlipressin decrease mortality
in HRS.
Sort P, Navasa M, Arroyo V, et al.: Effect of intravenous albumin on renal impairment and mortality in patients with
cirrhosis and spontaneous bacterial peritonitis. New England Journal of Medicine 1999; 341:403-409.
Gines P, Tito L, Arroyo V, et al.: Randomised comparative study of therapeutic paracentesis with and without
intravenous albumin in cirrhosis. Gastroenterology 1988; 94:1493-1502.
Gluud L, Kjaer M, Christensen E: Terlipressin for hepatorenal syndrome. Cochrane Database Systematic Reviews
2006; CD005162.
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Maintain renal perfusion
Correct metabolic derangements
Provide adequate nutrition
? Role of diuretics
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Human kidney has a compromised ability to
autoregulate in AKI.
Maintaining haemodynamic stability and
avoiding volume depletion are a priority in
AKI.
Kelleher S, Robinette J, Conger J: Sympathetic nervous system in the loss of autoregulation in acute renal failure.
American Journal of Physiology 1984; 246: F379-386.
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Current studies do not include patients with
established AKI.
The individual BP target depends on age, comorbidities (HTN) and the current acute
illness.
A generally accepted target remains MAP ≥
65.
Bourgoin A, Leone M, Delmas A, et al.: Increasing mean arterial pressure in patients with septic shock: Effects on
oxygen variables and renal function. Critical Care Medicine 2005; 33:780-786.
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SAFE study – no statistical difference between
volume resuscitation with saline or albumin in
survival rates or need for RRT.
Post – hoc analysis – albumin was associated
with increased mortality in traumatic brain
injury subgroup and improved survival in
septic shock patients.
Finfer S, Bellomo R, Boyce N, et al.: A comparison of albumin and saline for fluid resuscitation in the intensive
care unit. New England Journal of Medicine 2004; 350: 2247-2256.
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Fluid conservative therapy decreased
ventilator days and didn’t increase the need
for RRT in ARDS patients.
Association between positive fluid balance
and increased mortality in AKI patients.
Wiedeman H, Wheeler A, Bernard G, et al.: Comparison of two fluid management strategies in acute lung injury.
New England Journal of Medicine 2006; 354:2564-2575.
Payen D, de Pont A, Sakr Y, et al.; A positive fluid balance is associated with worse outcome in patients with acute
renal failure. Critical Care 2008; 12: R74.
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There is no evidence that from a renal
protection standpoint, there is a vasopressor
agent of choice to improve kidney outcome.
Dennen P, Douglas I, Anderson R,: Acute Kidney Injury in the Intensive Care Unit: An update and primer for the
Intensivist. Critical Care Medicine 2010; 38:261-275.
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“Renal” dose dopamine doesn’t reduce the
incidence of AKI, the need for RRT or improve
outcomes in AKI.
It may worsen renal perfusion in critically ill adults
with AKI.
Side effects of dopamine include increased
myocardial oxygen demand, increased incidence of
atrial fibrillation and negative immuno-modulating
effects.
Lauschke A, Teichgraber U, Frei U, et al.: “Low-dose” dopamine worsens renal perfusion in patients with acute
renal failure. Kidney 2006; 69:1669-1674.
Argalious M, Motta P, Khandwala F, et al.: “Renal dose” dopamine is associated with the risk of new onset atrial
fibrillation after cardiac surgery. Critical Care Medicine 2005; 33:1327-1332.