Prevention of Contrast-Induced Nephropathy in the Emergency Department
Received 25 August 2006; received in revised form 17 November 2006, 2 January 2007 and 13 January 2007; accepted 26 January 2007. published online 22 May 2007.
Study objective
Contrast-induced nephropathy is the third leading cause of hospital-acquired acute renal failure. Expanded use of contrast-enhanced imaging exposes an ever-widening number of patients to this renal toxin. We perform an evidence-based emergency medicine review comparing different therapies to prevent contrast-induced nephropathy. We limit our review to prophylactic therapies that are practical for an emergency department setting.
Methods
We searched MEDLINE, EMBASE, and the Cochrane Library for randomized trials comparing a wide range of medications to prevent contrast-induced nephropathy. We defined contrast-induced nephropathy by a commonly used surrogate measure of renal failure: a 25% or 0.5 mg/dL absolute increase in serum creatinine level from baseline 48 to 72 hours postcontrast. We limited our review to only trials for patients with baseline renal insufficiency, who are most at risk for contrast-induced nephropathy. We excluded prophylactic protocols requiring more than 2 hours precontrast to initiate and any trials of experimental medications or those that required invasive monitoring. We used standard criteria to appraise the quality of published trials.
Results
We found 7 randomized trials; 3 using N-acetylcysteine, 2 using theophylline, and 1 each using bicarbonate and ascorbic acid. Although many of these trials showed statistically significant reductions in the risk for contrast-induced nephropathy, none were sufficiently powered to detect reductions in mortality rate or the need for dialytic therapy.
Conclusion
Evidence from randomized trials shows that these interventions (theophylline, bicarbonate, and ascorbic acid) under review were appropriate to an ED setting and decreased the risk of contrast-induced nephropathy. The case for the effectiveness (N-acetylcysteine) was less certain.
Department of Emergency Medicine, State University of New York-Downstate Medical Center, Brooklyn, NY.
Address for correspondence: Richard Sinert, DO, Department of Emergency Medicine, Box 1228, SUNY–Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203; 718-245-2973, fax 718-245-4799
Supervising editor: Peter C. Wyer, MD
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ABSTRACT