What is the best hydration regimen to prevent contrast media-induced nephrotoxicity?

Background: Hydration is a commonly used method to prevent the decline in GFR after contrast media (CM) application. So far, there have been no controlled, randomized trials investigating the most effective route of fluid administration. Methods: Thirty-nine patients with normal renal function (65 9 years, serum creatinine 0.9 +/- 0.2 mg/dl, GFR = 110 +/- 31 ml/min/1.73 m(2)) receiving at least 80 ml of low-osmolality CM during an angiographic procedure were randomized to one of the following hydration regimens: Group 1: volume expansion with 300 ml saline during CM administration (n = 20, serum creatinine 0.8 +/- 0.1 mg/dl, GFR 119 +/- 27 ml/min/1.73 m(2)); Group 2: intravenous administration of at least 2,000 ml saline within 12 h before and after CM application (n = 19, serum creatinine 0.9 +/- 0.2 mg/dl, GFR 101 +/- 32 ml/min/1.73 m(2)). GFR was measured by CM clearance (Renalyzer) at baseline and 48 hours after CM administration. The primary end point was the mean change in the GFR after 48 hours, the secondary one was the incidence of CM-induced nephropathy (CWN), defined as a decrease in GFR of more than 50% from the baseline GFR within 48 hours. Results: Patients of group 1 showed a significantly (p < 0.05) higher decline in GFR (Delta GFR 34.6 +/- 25.7 ml/min/1.73 m(2)) compared to patients receiving the intravenous prehydration regimen (DeltaGFR 18.3 +/- 25.0 ml/min/1.73 m(2)). The incidence of CMIN was lower in prehydrated patients (5.3%) compared to the other group (15%). Conclusion: In patients with normal renal function, intravenous prehydration seems to be a very effective and feasible method to prevent the decline in GFR after contrast media exposure. Volume expansion given only during the CM exposure appears not to be sufficient enough to prevent renal damage.