1. ANTICOAGULATION IN CONTINUOUS RENAL REPLACEMENT THERAPY Dawn M Eding RN BSN CCRN Pediatric Critical Care Helen DeVos Children's Hospital

2. Goal of Anticoagulation  Maintain patency of CRRT circuit.  Minimize patient complications of anticoagulation therapies.

3. Sites of Clot Formation  Hemofilter  Bubble trap, dearation chamber  Catheter  Leurlock and 3 way stopcock connections

4. Factors Influencing Circuit Clotting and Filter Life  Vascular access  Blood flow  Circuit alarms  Anticoagulant

5. Vascular access  Site  Jugular  Subclavian  Femoral  Catheter size  Catheter connections

6. Vascular access needs to provide adequate flow to provide optimal therapy with minimal interruptions.

7. Properly functioning access is the key to successful CRRT therapy.

8. Blood Flow  Ideal flow rates 3-5ml/kg/minute  Access will ultimately determine blood flow

9. Circuit Alarms  Ideal circuit pressures

10. Anticoagulation Options  Citrate  Heparin  Citrate and low dose heparin  No anticoagulation

11. 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

12. 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

15. Citrate Infusion Titration Scale Circuit Ionized CalciumCitrate 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

16. 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

17. 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

18. 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.

19. 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.

20. 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

21. 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

22. Heparin Anticoagulation  Systemic anticoagulation  Requires monitoring of patient clotting times

23. 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

24. Potential Complications of Heparin  Patient bleeding  Heparin induced thrombocytopenia (HIT)

25. Citrate and Low Dose Heparin Anticoagulation  Continuous prefilter infusion of citrate and heparin  Maintain citrate per protocol  Heparin infusion of 5 units/kg/hour

26. No Anticoagulation  Typically results in short filter life

27. 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.