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Acute Renal Failure: Prevention and Treatment

　　Conditions that commonly contribute to medullary ischemia include decreased volume or pressure, exposure to nonsteroidal anti-inflammatory medications and dyes, and sepsis. What is known to work to prevent ARF is avoidance of nephrotoxins, any decrease in perfusion, provision of adequate hydration, and possibly once-a-day dosing of aminoglycosides.[4] What has not been demonstrated to be of benefit is the use of diuretics or dopamine.[1,5,6] Loop diuretics do not work to prevent dye- or ischemic-related renal injuries. Similarly, the preponderance of evidence to date, including a placebo-controlled randomized trial with 328 ICU patients[5] and a meta-analysis that included 18 randomized clinical trials,[6] found no change in mortality, incidence of renal failure, or need for dialysis with dopamine. While dopamine can increase urine output via several mechanisms, including vasodilatation through DA-1 receptors, increased cardiac output via beta-receptor stimulation, increased renal perfusion pressure via alpha-receptor effects, and inhibition of Na-K ATPase at the tubular epithelial level, there is no increase in medullary oxygenation. Indeed, the increased delivery of solutes to the distal tubule increases medullary work and, hence, may worsen ischemia. Dopamine may also increase bowel mucosal ischemia as well as causing tachyarrhythmias and pulmonary shunting.[7] Similarly, other agents, including other DA-1 agonists, atrial natriuretic peptide analogs, and adenosine or calcium antagonists, have not been shown to be effective in preventing renal failure.
　　A possible exception to the general lack of demonstrated efficacy from medications is the potential benefit demonstrated with the use of acetylcysteine in the prevention of radiographic contrast agent-induced reductions in renal function.[8] When used along with hydration, a lower incidence of renal dysfunction was seen in the active treatment group (n = 41), which received acetylcysteine twice daily on the day before and day of contrast agent administration. However, other antioxidants have not demonstrated benefit.
　　Once established, the treatment for renal failure has 2 primary goals: reversing the renal failure and preventing death. RRT represents the mainstay of therapy, with recent evidence supporting the concept that increased dialysis dose is associated with increased survival.[9] The potential benefit of continuous vs intermittent renal replacement techniques (CRRT vs. IHD) was discussed and remains an issue under active debate. Membrane biocompatibility is well established as an important factor that influences outcome, with synthetic membranes demonstrating superiority over cellulose membranes.
　　Dr. Kellum noted that despite an increase in the number of patients developing ARF, the advances made in the understanding of renal physiology, and technical capabilities, consensus regarding optimal therapeutic strategies remains lacking. In an attempt to standardize care and to direct further research, the Acute Dialysis Quality Initiative (which can be accessed at www.adqi.com) was developed.