Use of isotonic sodium bicarbonate to prevent radiocontrast nephropathy in patients with mild pre-existing renal impairment: a meta-analysis.

Acute renal dysfunction after radiocontrast in patients with pre-existing renal impairment is not uncommon and is associated with significant morbidity and mortality. Isotonic sodium bicarbonate solution was first reported to reduce radiocontrast nephropathy in 2004. This first study was, however; limited by its small sample size and as such, the use of isotonic sodium bicarbonate to prevent radiocontrast nephropathy is still not widely used by many anaesthetists and intensivists. We meta-analysed relevant randomised controlled studies sourced from the Cochrane Controlled Trial Register (2007 issue 4), EMBASE and MEDLINE databases (1966 to April 15, 2008) without any language restriction. The use of isotonic sodium bicarbonate was associated with a significant reduction in risk of an incremental rise in serum creatinine concentration 25% above baseline (relative risk 0.22, 95% confidence interval [CI]: 0.11 to 0.44, P < 0.0001; 2 = 0%) and had a protective effect on the absolute change in serum creatinine concentration (weighted-mean-difference -9.4 micromol/l, 95% CI: -17.2 to -1.7, P = 0.02; F = 0%) and creatinine clearance (weighted-mean-difference 3.7 ml/min, 95% CI: 0.55 to 6.80, P = 0.02; F = 57.1%) after radiocontrast. The incidence of acute renal failure requiring dialysis was low (1.4%) and was not significantly different after the use of isotonic sodium bicarbonate (relative risk 0.59, 95% CI: 0.15 to 2.42, P = 0.47; F = 0%). With the limited data available, isotonic sodium bicarbonate appears to be safe and very effective in reducing radiocontrast nephropathy in patients with mild pre-existing renal impairment. A large randomised controlled study is needed to confirm whether isotonic bicarbonate can improve patient centred clinical outcomes.