1. Do we know what we mean?

2.  There are more than 35 definitions of AKI (formerly acute renal failure) in literature!  Mehta R, Chertow G: Acute renal failure definitions and classification: Time for change? Journal of American Society of Nephrology 2003; 14:2178-2187.

3.  RIFLE classification  AKIN classification

4. 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.

5.  Modification of the RIFLE classification by Acute Kidney Injury Network (AKIN).  Recognizes that small changes in serum creatinine (>0.3 mg/dl) adversely impact clinical outcome.  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; 50:712- 720.

6. AKIN stage Serum Creatinine Criteria Urinary Output Criteria Time 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 AKIN classification * 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.

7.  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 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.

8. 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.

9.  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 50- 70%.  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; 294:813- 818. 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.

10.  Serum Creatinine  Urine Output  Time

11. 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.

12.  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.

13.  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.

14.  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.

15.  Recognition of underlying risk factors ◦ 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.

16.  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.

17.  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.

18.  Maintain renal perfusion  Correct metabolic derangements  Provide adequate nutrition  ? Role of diuretics

19.  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.

20.  Current studies do not include patients with established AKI.  The individual BP target depends on age, co- morbidities (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.

21.  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.

22.  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.

23.  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.

24.  “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.