Continuous venovenous hemofiltration with citrate-based replacement fluid: efficacy, safety, and impact on nutrition

Citrate-based continuous venovenous hemofiltration (CVVH) replacement fluids provide effective and simple regional anticoagulation. However, concern over toxicity has limited citrate use, especially at the high filtration rates advocated for better outcomes. We used volumes of 72 L/d in patients at high risk for bleeding and investigated the treatment's efficacy, safety, and clinical results, especially with regard to nutrition supplementation.

A standard replacement solution (trisodium citrate, 13.3 mmol/L) was infused at up to 3 L/h in predilution CVVH, and ultrafiltration was increased further for net fluid removal. Calcium was repleted centrally. We retrospectively evaluated metabolic control, citrate toxicity, circuit patency, hemorrhagic complications, hemodynamics, vasopressor use, nutrition, renal recovery, and mortality.

Seventy-six patients with 766 CVVH patient-days were analyzed. Mean replacement fluid rate was 31 mL/kg/h (35 mmol/h of citrate), with hemofiltration of 35 mL/kg/h (67 +/- 11 L/d). No significant bleeding, citrate toxicity, or hypocalcemia was observed, and 74% required additional alkali therapy. Dialyzer patency was 58% at 48 hours. Control of fluid, electrolytes, and azotemia was excellent (serum creatinine level, 1.7 mg/dL [150 micromol/L]; blood urea nitrogen, 42 mg/dL [15 mmol/L]). Fluid removal permitted protein (1.7 g/kg/d) and calorie (30 kcal/kg/d) nutrition in high fluid volumes. Vasopressor use and central pressures decreased significantly. Cumulative 28-day intensive care unit survival was 58%, and 41% of these patients had renal recovery in the intensive care unit. Thirty percent of the entire cohort survived the hospitalization, and 53% of these patients recovered renal function.

CVVH with 3 L/h of citrate-based replacement fluid is a safe, efficient, and simple technique in patients at high risk for bleeding. It allows superb control of uremia and fluid balance and thereby permits aggressive nutritional support.