Sodium Chloride vs. Sodium Bicarbonate for the Prevention of Contrast Medium-Induced Nephropathy: A Randomized Controlled Trial
What is the relative effectiveness of sodium chloride compared with sodium bicarbonate for prevention of contrast-induced nephropathy (CIN)?
The authors enrolled 258 consecutive patients with renal insufficiency undergoing intravascular contrast procedures. Patients were randomized to one of the three hydration strategies: sodium chloride 0.9% 1 ml/kg/h for at least 12 hours prior to and 12 hours after the procedure, or sodium bicarbonate (166 mEq/L) 3 ml/kg for 1 hour before and 1 ml/kg/h for 6 hours after the procedure, or sodium bicarbonate (166 mEq/L) 3 ml/kg over 20 minutes before the procedure plus sodium bicarbonate orally (500 mg per 10 kg). The primary endpoint was the change in estimated glomerular filtration rate (eGFR) within 48 hours after contrast. Development of CIN was a secondary endpoint.
The baseline GFR of the cohort was 43 ± 11 ml/min/1.73 m2. Approximately 45% of the patients underwent computed tomography scanning, 23% underwent cardiac catheterization, and 21% underwent percutaneous coronary intervention. The median contrast dose was 100 ml. The maximum change in eGFR was significantly greater in the sodium bicarbonate arm (7 hours) compared with normal saline (mean difference, -3.9 [95% confidence interval, -6.8 to -1] ml/min/1.73 m2; p = 0.009) and similar between the two bicarbonate arms (mean difference, 1.3 [95% confidence interval, -1.7-4.3] ml/min/1.73 m2; p = 0.39). The incidence of CIN was significantly lower in the normal saline arm (1%) compared with the two bicarbonate arms (9% in the 7-hour infusion and 10% in the brief infusion).
The authors concluded that volume supplementation with 24-hour sodium chloride 0.9% is superior to sodium bicarbonate for the prevention of CIN.
The choice of hydration fluid for prevention of CIN remains controversial in part due to multiplicity of small trials with different endpoints. These trials have produced conflicting results, but in general, 12 hours of saline prior to and 12 hours after contrast exposure remains the gold standard for prophylaxis of CIN. When shorter duration of saline hydration has been compared with sodium bicarbonate, there appears to be some benefit in association with use of sodium bicarbonate. Of note, none of the trials or the meta-analysis has demonstrated a reduction in need for dialysis (Meier P, et al., BMC Med 2009;7:23). This study does little to clarify the debate, and an adequately powered multicentric trial is needed to define the hydration strategy for prophylaxis of CIN.
Keywords: Cardiac Catheterization, Sodium Bicarbonate, Percutaneous Coronary Intervention, Contrast Media, Renal Dialysis, Incidence, Renal Insufficiency, Sodium Chloride, Kidney Diseases, Bicarbonates, Tomography, Glomerular Filtration Rate, Confidence Intervals
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