Using Lactated Ringer's as a Prefilter Fluid in CRRT to Reduce Clotting
Lactated Ringer's solution should not be used as a prefilter fluid in CRRT, especially in patients with circulatory shock, liver failure, or lactic acidemia, as bicarbonate-based solutions are recommended instead.
Recommended Anticoagulation Strategies for CRRT
- Regional citrate anticoagulation is the preferred method for preventing filter clotting in CRRT for patients without contraindications to citrate 1
- For patients who cannot receive citrate, unfractionated or low-molecular-weight heparin should be used as anticoagulation during CRRT 2
- Direct thrombin inhibitors (argatroban) or Factor Xa inhibitors should be used in patients with heparin-induced thrombocytopenia 2
Buffer Solutions in CRRT
- Bicarbonate is recommended over lactate as a buffer in dialysate and replacement fluid for CRRT in patients with AKI 2
- Bicarbonate is strongly recommended (1B recommendation) over lactate for patients with AKI and circulatory shock 2
- Bicarbonate is suggested (2B recommendation) over lactate for patients with AKI and liver failure and/or lactic acidemia 2
Prefilter Fluid Administration Considerations
- Prefilter fluid administration can help reduce filter clotting by diluting the blood before it enters the hemofilter 1
- This approach is particularly beneficial in high-volume continuous venovenous hemofiltration (CVVH) where filter clotting is more common 1
- Replacement fluid used for prefilter administration should contain physiologic concentrations of electrolytes 1
Lactated Ringer's vs. Other Solutions
- While lactated Ringer's has been shown to produce hypercoagulability compared to normal saline in some hemorrhagic shock models 3, this effect is not desirable in CRRT where filter clotting is a concern
- In critically ill patients, no significant differences in clinical outcomes have been observed between balanced crystalloid solutions (comparing Normosol-R vs. lactated Ringer's) 4
- The KDIGO guidelines specifically recommend bicarbonate-based solutions over lactate-based solutions for CRRT 2
Monitoring and Practical Considerations
- Transmembrane and filter pressures should be closely monitored as increases in these pressures are associated with a higher risk of circuit clotting 5
- Maintaining higher activated clotting times (ACTs) may decrease the risk of circuit clotting 5
- Ensure proper fluid balance monitoring during CRRT, as errors in fluid balance can occur with various infusion setups 6
Conclusion
Based on the KDIGO guidelines, bicarbonate-based solutions are preferred over lactate-based solutions like Lactated Ringer's for CRRT, particularly in patients with circulatory shock, liver failure, or lactic acidemia. Regional citrate anticoagulation remains the first-line strategy to prevent filter clotting in CRRT for patients without contraindications.