Dr Farmer Prevention and Treatment of Acute Kidney Injury in the ICU Prevention and Treatment of Acute Kidney Injury in the ICU J Christopher Farmer Learning Objectives To discuss… – – – – Pathophysiology, risk factors, and etiologies of AKI Current and emerging methods of early diagnosis Prevention of AKI Treatment of AKI Epidemiology and Pathophysiology Increasing Incidence of AKI Nash, et al: Am J Kidney Dis; 2002, 39:390 Arterial Vasodilatation and Renal Vasoconstriction in Patients with Sepsis Diagnosis and Classification of AKI Diagnostic Criteria for AKI An abrupt (within 48 hours) reduction in kidney function currently defined as: 1.An absolute increase in serum creatinine of more than or equal to 0.3 mg/dl, or 2.A percentage increase in serum creatinine of more than or equal to 50% (1.5 fold from baseline), or 3.A reduction in urine output (documented oliguria of less than 0.5 ml/kg per hour for more than hours) Mehta et al: Critical Care; 2007, 11:R31-R39 “RIFLE” Criteria for AKI Bellomo & the ADQI workgroup: Critical Care; 2004, 8:R204-R212 Future “Cardiac Biomarkers” of AKI? Parikh et al: KI; 2006, 70:199 -203 Coming soon? Biomarker Sample Source Assay Commercial Development NGAL plasma Western blot In development (Biosite) NGAL urine Western blot In development (Abbott) IL-18 urine ELISA NONE KIM-1 urine ELISA NONE Cystatin-C plasma Immunonephelometry In development (DadeBehring) Prevention of AKI Prevention of AKI ➼ ? X Venkataraman, et al: Crit Care Med; 2008, 36:S166-S171 Maintaining Renal Perfusion Pressure      No absolute number is considered adequate with regard to mean arterial pressure, and target mean arterial pressure should be individualized based on the patient's baseline physiology Vasopressors should be used to improve perfusion pressure only after adequate volume repletion is accomplished No reliable evidence that norepinephrine is associated with increased risk of AKI when used to treat arterial hypotension Intra-abdominal hypertension is associated decreased renal perfusion and may result in AKI Prompt recognition, monitoring, and early surgical treatment offer the best potential for recovery Role of Loop Diuretics in AKI   maintaining a greater urine flow to flush out the tubules with loop diuretics has been advocated to prevent AKI Two meta-analyses have pooled studies evaluating the role of loop diuretics in the prevention of AKI – – The first systematic review compared fluids alone with diuretics in people at risk for AKI from various causes and found no benefit from diuretics with regard to its incidence, need for dialysis, or mortality In the second recent meta-analysis (RCTs, n = 849 patients), no difference among patients treated with loop diuretics was found in hospital mortality, need for renal replacement therapy, or number of dialysis sessions needed Treatment of AKI Principles of Solute Transport in Hemodialysis and Hemofiltration John et al: Chest 2007;132:1379-1388 Hemofiltration versus Hemodiafiltration Definitions of RRT Modalities Pannu et al: JAMA; 2008, 299: 793-805 Renal Replacement Therapy in Patients with Acute Renal Failure Pannu et al: JAMA; 2008, 299: 793-805 Standard IHD versus Slow Low Efficiency Dialysis (SLED) Initiation of RRT John, S et al Chest 2007;132:1379-1388 Potential Complications with CRRT Conclusions  Prevention of AKI is better than treatment of AKI – –  Prognosis and mortality Maintain renal perfusion status, treat sepsis promptly, avoid nephrotoxins Be familiar with the various modalities of renal replacement therapies