Acute renal failure is characterised by abrupt and sustained decline in glomerular filtration rate, which leads to accumulation of urea and other chemicals in the blood. The term acute kidney injury has been introduced to encompass a wide spectrum of acute alterations in kidney function from mild to severe. Acute kidney injury is classified according to the RIFLE criteria, in which a change from baseline serum creatinine or urine output determines the level of renal dysfunction.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent acute kidney injury in people at high risk? What are the effects of treatments for critically ill people with acute kidney injury? We searched: Medline, Embase, The Cochrane Library, and other important databases up to December 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 82 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: albumin supplementation plus loop diuretics (intravenous), aminoglycosides, aminophylline, amphotericin B, calcium channel blockers, contrast media, dialysis membranes, dopamine, early versus late dialysis, extended daily dialysis, fenoldopam, loop diuretics, mannitol, N-acetylcysteine, natriuretic peptides, renal replacement therapy, sodium bicarbonate-based fluids, sodium chloride-based fluids, and theophylline.
Acute renal failure (also called acute kidney injury) is characterised by abrupt and sustained decline in GFR, which leads to accumulation of urea and other chemicals in the blood.
It can be classified according to a change from baseline serum creatinine or urine output, with "Risk" being defined by either a 50% increase in serum creatinine, or a urine output of <0.5 mL/kg/hour for at least 6 hours; and "Failure" being defined by a three-fold increase in serum creatinine, or a urine output of <0.3 mL/kg/hour for 24 hours.
In people at high risk of developing acute renal failure, intravenous sodium chloride (0.9%) reduces incidences of acute renal failure compared with unrestricted oral fluids or 0.45% intravenous sodium chloride solution.
N-acetylcysteine plus intravenous fluids may reduce contrast nephropathy compared with intravenous fluids alone in people undergoing contrast nephrography, although data about prevention of renal failure are inconclusive.
Sodium bicarbonate may be as effective as sodium chloride but the evidence is conflicting so we cannot draw conclusions.
Low-osmolality contrast medium is less nephrotoxic compared with high-osmolality media, and iso-osmolar contrast media has similar nephrotoxicity to low-osmolar contrast media. We found insufficient evidence on the effects of prophylactic renal replacement therapy.
Single-dose aminoglycosides seem as beneficial as multiple doses for treating infections, but are less nephrotoxic.
Lipid formulations of amphotericin B may cause less nephrotoxicity than standard formulations, although the evidence for this is somewhat sparse.
Mannitol, theophylline, aminophylline, fenoldopam, and calcium channel blockers do not seem useful treatments for people at high risk of acute renal failure.
We don't know whether continuous renal replacement therapy is any more effective than intermittent renal replacement therapy. High-dose continuous renal replacement therapy was ineffective in treatment of people critically ill with acute kidney injury, and is also associated with an increased risk of hypophosphataemia, hypokalaemia, and hypotension.
Synthetic dialysis membranes may be associated with improved survival compared with cellulose-based membranes for treating people with acute renal failure; however, evidence is inconclusive and of variable quality.
Loop diuretics plus fluids seem to increase the risk of developing acute renal failure compared with fluids alone, both in high-risk and critically ill people, and do not seem to improve renal function or mortality compared with placebo in people with acute renal failure, but may increase the risks of ototoxicity and volume depletion.We found no evidence that examined whether intravenous albumin supplementation improved the effects of loop diuretics, or whether continuous infusion was any more effective than bolus injection in the treatment of people critically ill with acute renal failure.
Neither natriuretic peptides nor dopamine seem beneficial in either high-risk or critically ill people, and both are associated with significant adverse effects.
We don't know whether early versus late renal replacement therapy or extended daily dialysis improve outcomes in people critically ill with acute kidney injury.