title: A novel method for regional citrate anticoagulation in continuous venovenous hemofiltration (CVVHF).
abstract: BACKGROUND
  Continuous renal replacement therapy (CRRT) is increasingly used in managing acute renal failure (ARF) as it offers hemodynamic stability and significant solute clearance in this setting. However, it also requires anticoagulation. Traditionally, heparin has been the anticoagulant of choice but this increases hemorrhagic risk in already high-risk ARF patients. Regional citrate anticoagulation offsets this risk. However, it can be difficult to manipulate regional anticoagulation in CRRT. Moreover, citrate CRRT has been plagued by short optimal filter patency times.
  
  
  METHODS
  We designed a novel citrate-based anticoagulation schema for continuous venovenous hemofiltration (CVVHF). We implemented this schema prospectively in caring for 24 individuals admitted to the intensive care unit with ARF requiring CRRT. Each individual had a contraindication to systemic anticoagulation. We evaluated filter patency using Kaplan-Meier methodology, comparing the effect of this citrate-CVVHF system to historical, saline-flush control CVVHF systems.
  
  
  RESULTS
  58 filters ran for a total of 2637.5 h. Average filter patency time was 45.4 +/- 25.5 h. At 48 h, 70% of the CVVHF-citrate system filters remained patent compared to only 16% of historical control saline-flush systems (p = 0.0001). The average filtered urea nitrogen/blood urea nitrogen ratio was 0.84 +/- 0.06 with an average urea clearance of 28.5 +/- 4.1 mL/min for CVVHF-citrate-treated individuals. Only three patients experienced transient complications related to CVVHF-citrate with resolution of these complications within 24 h. Ultimately, 58.3% of the CVVHF-citrate-treated patients survived to ICU discharge.
  
  
  CONCLUSIONS
  This novel CVVHF-citrate system achieved excellent clearance and dramatically improved filter patency compared to saline-flush systems. Moreover, it did so with minimal toxicity.
authors.affiliation: Department of Medicine, University of Wisconsin, Madison 53705,USA.
authors.forename: R Michael
authors.initials: RM
authors.lastname: Hofmann
authors.forename: Christine
authors.initials: C
authors.lastname: Maloney
authors.forename: David M
authors.initials: DM
authors.lastname: Ward
authors.forename: Bryan N
authors.initials: BN
authors.lastname: Becker
mesh_terms: D058186:Acute Kidney Injury / Q000401:mortality / Q000628:therapy; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D001806:Blood Urea Nitrogen; D019343:Citric Acid / Q000009:adverse effects / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D005260:Female; D006440:Hemofiltration / Q000009:adverse effects / Q000295:instrumentation; D017052:Hospital Mortality; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014922:Wisconsin
chemical_list: D000925:Anticoagulants; D019343:Citric Acid