Using hydration with sodium bicarbonate rather than with saline (sodium chloride) solution may help negate the adverse effects of contrast agents. An increasing number of diagnostic procedures make use of a radiographic contrast agent (dye) in order to obtain useful x-ray images of internal organs. Contrast agents are widely used in procedures involving heart catheterization (angiography and angioplasty) and CT scanning. Contrast agents contain large amounts of iodine and can, unfortunately, be very hard on the kidneys. It is estimated that more than 10% of hospital-acquired renal failure (nephropathy) is due to the use of contrast agents. Supplementation with N-acetylcysteine for two days prior to and after the procedure has been found to reduce the incidence of contrast-induced nephropathy (CIN) in a small clinical trial.
Researchers at the Carolinas Medical Center now report that using sodium bicarbonate rather than sodium chloride in the hydration fluid employed during the procedure can markedly reduce the incidence of CIN. Their clinical trial involved 119 patients scheduled to undergo a procedure using contrast agents. All patients had serum creatinine levels of at least 1.1 mg/dL (97.2 micromol/L). Patients were randomized to receive the standard saline infusion (containing sodium chloride) before and after the administration of the contrast agent (iopamidol) or to receive similar infusions in which the sodium chloride had been replaced with sodium bicarbonate.
While 8 patients (13.6%) in the sodium chloride group experienced kidney failure only 1 patient (1.7%) did
so in the sodium bicarbonate group. All the patients who experienced kidney failure (CIN) had undergone
heart catheterization procedures. The researchers followed up their findings in another trial involving 191
patients who all received the sodium bicarbonate-based hydration fluid. The incidence of CIN in this group
was 1.6%. The researchers conclude that infusion of sodium bicarbonate before and after procedures using
contrast agents may provide an inexpensive, safe, practical, and simple method for preventing CIN.