Lactate-buffered peritoneal solution traditionally has been used as dialysate for continuous renal replacement therapy (CRRT) in the United States because no bicarbonate solution is commercially available. Since 1994, the Cleveland Clinic Foundation Dialysis Unit has prepared a bicarbonate solution (sodium 144 +/- 3 mEq/L, HCO3 37 +/- 2 mEq/L, potassium 3 or 4 mEq/L, calcium 3.0 +/- 0.3 mEq/L, and magnesium 1.4 +/- 0.3 mg/dL) replicating the dialysate for chronic intermittent hemodialysis. No solute precipitation, as calcium or magnesium salts, were observed, and several cultures of the solution, performed at various time periods, remained negative. Fifty critically ill acute renal failure patients have been treated with bicarbonate-CRRT. All patients were in multiple organ failure and required mechanical ventilation; 37 were receiving vasopressors. Forty-four continuous venovenous hemodialysis sessions and eight continuous arteriovenous hemodialysis sessions were performed with a mean duration of 7.8 +/- 6.1 days. The mean inflow dialysate rate was 1,249 +/- 225 mL/hr and the mean outflow rate (dialysate plus ultrafiltration) was 1,399 +/- 237 mL/hr; the inflow rate was constantly kept lower or equal to the outflow rate to avoid an enhanced potential for backfiltration. No related fever spikes or sepsis episodes were noted.(ABSTRACT TRUNCATED AT 250 WORDS)