Regional Citrate Anticoagulation

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• Regional Citrate Anticoagulation
• during CVVH in the
• Pediatric Intensive Care Unit

T Gaillot, V Phan, P Jouvet, F Gauvin, C Litalien
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Introduction

• CVVH is being increasingly utilized for the care
  of PICU patients
• Imperative need
• Effective anticoagulation to prevent recurrent
  clotting of the extracorporeal circuit and to
  achieve efficient and uninterrupted therapy
• Historically, systemic anticoagulation with
  heparin
• ? mainstay of anticoagulation for CVVH
• Limits/contraindications
• High risk for bleeding
• Active bleeding
• Heparin-induced thrombocytopenia
• Use of activated Protein C

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Introduction

• Regional citrate anticoagulation (RCA)
• Attractive alternative to systemic heparinization
  with less risk of bleeding
• Citrate chelates ionized Ca2, an essential
  cofactor in the clotting cascade
• Anticoagulation is limited to the extracorporeal
  circuit by infusing citrate solution into the
  arterial limb of the circuit
• Systemic anticoagulation is avoided by restoring
  ionized Ca2 in the systemic circulation by
  infusing Ca2 solution through a separate central
  line

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Introduction

• RCA and mean circuit lifetime
• Adult studies
• Monchi et al, 2004 RCA vs heparin 70 h vs 40 h
  
• Dorval et al, 2003 44 ? 24 h
• Pediatric studies
• Chadha et al, 2002 51 ? 8 h
• Elhanan et al, 2004 56 ? 22 h
• Bunchman et al, 2002 71 ? 7 h

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Introduction

• RCA and complications
• Citrate is metabolized in the liver and produces
  HCO3- and citric acid
• ? can result in metabolic alkalosis
• Accumulation of citrate may occur if liver
  metabolism is impaired
• ? can result in citrate toxicity or "citrate
  gap"

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Objective

• To evaluate the mean circuit lifetime and
• metabolic complications of RCA in critically ill
• children after the introduction of this
• anticoagulation technique in our PICU

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Material and methods

• Retrospective chart review
• Children who underwent hemofiltration with RCA
  from March 2003 to December 2003 were included
• Mean circuit lifetime (MCL) and reasons for
  circuit discontinuation were determined
• Metabolic alkalosis pH ? 7.45 and HCO3- ? 30
  mmol/L
• Citrate gap total to ionized Ca2 ratio gt 2.5

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Material and methods
Normocarb Rate 2 L/1.73 m2/h
Systemic infusion Calcium chloride (8g/1L NS)
Rate 0.4 X ACD-A rate
ACD-A Rate 1.5 X BFR
DIALIZER Prisma M-10, M-60 or M-100 (AN-69)
From patient
To patient
BFR 2-8 ml/kg/min
Ultrafiltrate
Normocarb Rate 2 L/1.73 m2/h
Bunchman et al , 2002
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(No Transcript)
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Results Kaplan-Meier curve of time to circuit
discontinuation
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Results

• Post filter ionized Ca2 0.40 ? 0.10 mmol/L
• Patient ionized Ca2 1.14 ? 0.13 mmol/L
• 13 episodes (35 ) of metabolic alkalosis in 4
  patients
• 9 episodes (24 ) of citrate gap in 2 patients

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Conclusion

• In our PICU, the mean circuit lifetime using RCA
  was much shorter than those reported despite
  post-filter ionized Ca2 within the optimum range
• Metabolic alkalosis was frequently encountered
• Citrate toxicity occurred in 2 patients out of 5
• The use of RCA may be somewhat problematic in
  some critically ill children

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Perspectives

• RCA remains an attractive option to provide
  anticoagulation in those patients with heparin
  contraindications
• Prospective, randomized controlled trials
  comparing RCA and systemic heparinization are
  needed before RCA replaces heparin in all
  critically ill children