BICARBONATE DIALYSATE FOR CONTINUOUS RENAL REPLACEMENT THERAPY IN INTENSIVE-CARE UNIT PATIENTS WITH ACUTE-RENAL-FAILURE

Lactate-buffered peritoneal solution traditionally has been used as di alysate for continuous renal replacement therapy (CRRT) in the United States because no bicarbonate solution is commercially available. Sinc e 1994, the Cleveland Clinic Foundation Dialysis Unit has prepared a b icarbonate solution (sodium 144 +/- 3 mEq/L, HCO3 37 +/- 2 mEq/L, pota ssium 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 hemodialy sis. No solute precipitation, as calcium or magnesium salts, were obse rved, and several cultures of the solution, performed at various time periods, remained negative. Fifty critically ill acute renal failure p atients have been treated with bicarbonate-CRRT. All patients were in multiple organ failure and required mechanical ventilation; 37 were re ceiving vasopressors. Forty-four continuous venovenous hemodialysis se ssions and eight continuous arteriovenous hemodialysis sessions were p erformed with a mean duration of 7.8 +/- 6.1 days. The mean inflow dia lysate rate was 1,249 +/- 225 mL/hr and the mean outflow rate (dialysa te plus ultrafiltration) was 1,399 +/- 237 mL/hr; the inflow rate was constantly kept lower or equal to the outflow rate to avoid an enhance d potential for backfiltration. No related fever spikes or sepsis epis odes were noted. The metabolic control achieved during bicarbonate-CRR T was good, with the following mean (+/-SD) daily values: blood urea n itrogen 70.3 +/- 29.0 mg/dL, creatinine 3.6 +/- 1.3 mg/dL, sodium 135. 7 +/- 3.7 mEq/L, potassium 4.6 +/- 0.5 mEq/L, chloride 99.9 +/- 4.6 mE q/L, carbon dioxide content 21.4 +/- 3.4 mEq/L, calculated anion gap 1 4.4 +/- 4.8 mEq/L, arterial pH 7.39 +/- 0.05, arterial PCO2 36.6 +/- 5 .4 mm Hg, total calcium 8.7 +/- 0.9 mg/dL (corrected for albumin 9.6), phosphorus 4.2 +/- 1.4 mg/dL, and magnesium 2.06 +/- 0.26 mg/dL. A su bgroup of 13 patients was treated with two dialysate types, lactate-ba sed solution (Dianeal 1.5%; Baxter Healthcare Corporation, Deerfield, IL) for 3.2 +/- 1.5 days and bicarbonate solution for 7.4 +/- 1.6 days , and the obtained metabolic control under both types of dialysate was compared. Mean values +/- SD (with probability values) obtained with lactate dialysate versus bicarbonate dialysate were as follows: blood urea nitrogen 77.6 +/- 34.4 mg/dL versus 71.0 +/- 20.8 mg/dL (P = NS), creatinine 4.1 +/- 0.9 mg/dL versus 3.3 +/- 1.6 mg/dL (P = NS), sodiu m 132.8 +/- 4.8 mEq/L versus 135.6 +/- 2.9 mEq/L (P = 0.04), chloride 95.8 +/- 5.4 mEq/L versus 98.5 +/- 4.2 mEq/L (P = NS), carbon dioxide content 17.8 +/- 3.1 mEq/L versus 21.8 +/- 3.4 mEq/L (P = 0.002), calc ulated anion gap 19.3 +/- 4.4 mEq/L versus 15.2 +/- 3.8 mEq/L (P = 0.0 08), arterial pH 7.36 +/- 0.07 versus 7.40 +/- 0.06 (P = NS), arterial PCO2 32.1 +/- 5.3 mm Hg versus 37.8 +/- 3.8 mm Hg (P = 0.01), total c alcium 8.3 +/- 1.1 mg/dL versus 8.8 +/- 1.0 mg/dL (P = NS), phosphorus 4.7 +/- 1.3 mg/dL versus 3.8 +/- 1.4 mg/dL (P = NS), magnesium 1.95 /- 0.14 mg/dL versus 2.04 +/- 0.34 mg/dL (P = NS), and glucose 200.5 /- 80.4 mg/dL versus 146.7 +/- 40.4 mg/dL (P = 0.04). The bicarbonate solution is simple to prepare and is cost-effective. In our experience , its use as dialysate for CRRT is safe, free of complications, and pr ovides an excellent metabolic control. (C) 1995 by the National Kidney Foundation, Inc.