The effect of mannitol on renal function after cardiopulmonary bypass in patients with established renal dysfunction.

The usefulness of mannitol in the priming fluid for cardiopulmonary bypass is uncertain in patients with normal renal function, and has not been studied in patients with established renal dysfunction. We studied 50 patients with serum creatinine between 130 and 250 micromol.l(-1) having cardiac surgery. Patients were randomised to receive mannitol 0.5 g.kg(-1), or an equivalent volume of Hartmann's solution, in the bypass prime. There were no differences between the groups in plasma creatinine or change in creatinine from baseline, urine output, or fluid balance over the first three postoperative days. We conclude that mannitol has no effect on routine measures of renal function during cardiac surgery in patients with established renal dysfunction.