ANTICOAGULATION IN CONTINUOUS RENAL
REPLACEMENT THERAPY
Dawn M EdingRN BSN CCRN
Pediatric Critical CareHelen DeVos Children's Hospital
Goal of Anticoagulation Maintain patency of CRRT circuit. Minimize patient complications of
anticoagulation therapies.
Sites of Clot Formation Hemofilter Bubble trap, dearation chamber Catheter Leurlock and 3 way stopcock
connections
Factors Influencing Circuit Clotting and
Filter Life Vascular access Blood flow Circuit alarms Anticoagulant
Vascular access Site
Jugular Subclavian Femoral
Catheter size Catheter connections
Vascular access needs to provide adequate flow to provide optimal therapy with minimal interruptions.
Properly functioning access is the key to successful CRRT therapy.
Blood Flow Ideal flow rates
3-5ml/kg/minute Access will ultimately determine
blood flow
Circuit Alarms Ideal circuit pressures
Anticoagulation Options Citrate Heparin Citrate and low dose heparin No anticoagulation
Citrate Anticoagulation Regional anticoagulation of the CRRT
system Coagulation is a calcium dependent process Citrate acts by binding calcium Less risk of bleeding Commercially available solutions exist
Citrate Protocol Infused pre filter Start infusion at 1.5 times blood flow rate Requires monitoring of circuit and patient ionized
calcium levels Adjust infusion based on post filter ionized calcium
levels Aim for post-filter ionized calcium level between 0.25 and 0.4 mmols/L
Requires calcium free dialysate and replacement solutions
Citrate Infusion Titration Scale
Circuit Ionized Calcium
Citrate infusion adjustment
< .25 rate by 10 mL/hour
0.25 – 0.39 (optimum range)
No adjustment
0.4 – 0.5 rate by 10 mL/hour
> 0.5 rate by 20 mL/hour
Potential Complication of Citrate: Hypocalcemia
Infusion of calcium chloride solution to patient via a central venous access is necessary to avoid hypocalcemia.
Solution consists of 8gm Calcium Chloride in 1L NS Start infusion at 40% of citrate flow rate Adjust calcium chloride infusion based on
patient ionized calcium levels Aim for patient ionized calcium level of 1.1
to 1.3 mmols/L
Calcium Chloride Titration Scale
Patient ionized calcium (mmol/L)
Calcium Infusion Adjustment
> 1.3 rate by 10 mL/hour
1.1 – 1.3 (optimum range)
No adjustment
0.9 – 1.1 rate by 10 mL/hour
< .9 rate by 20 mL/hour
Potential Complication of Citrate: Metabolic Alkalosis Related to rate of citrate metabolism in liver Citrate converts to HCO3 (1 mmol of citrate
converts to 3 mmols of HCO3) Correction of alkalosis can be done by
adjusting the bicarbonate concentration in replacement and dialysate solutions, decreasing the citrate rate, or by infusing 0.9% normal saline (pH 5.4) as a replacement or dialysate solution.
Potential Complication of Citrate:Hyperglycemia ACDA solution contains 2.45gm/dl of
dextrose Adjustments in other dextrose sources (TPN etc.) and/or insulin infusions may become necessary.
Potential Complication of Citrate: Citrate Lock Seen with rising patient total calcium
while patient’s ionized calcium is in normal range or dropping
Essentially the delivery of citrate exceeds the hepatic metabolism and CRRT clearance
Treatment of Citrate Lock Decrease citrate rate Adjust scale of acceptable post filter
ionized calcium range Stop citrate infusion for 10-30 minutes
and restart at a lower rate Increase clearance by adjusting
Replacement and/or Dialysate flow rates
Heparin Anticoagulation Systemic anticoagulation Requires monitoring of patient clotting
times
Heparin Protocol Continuous infusion of 10-20
units/kg/hour Infused prefilter Loading dose may be needed Monitor postfilter activated clotting time
(ACT) Titrate heparin infusion to maintain ACT range of 180-220 seconds
Potential Complications of Heparin Patient bleeding Heparin induced thrombocytopenia (HIT)
Citrate and Low Dose Heparin Anticoagulation Continuous prefilter infusion of citrate and heparin Maintain citrate per protocol Heparin infusion of 5 units/kg/hour
No Anticoagulation Typically results in short filter life
Conclusions: Wide range of practice exists. Despite all best measures filters last
from hours to days. Individual circumstances of the patient
dictate the anticoagulation regimen that is best for the patient.
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