What is the recommended heparin (unfractionated heparin) regimen for patients undergoing dialysis?

Heparin Regimen for Dialysis

For patients undergoing dialysis, the recommended unfractionated heparin regimen is 25-30 units/kg as an initial bolus followed by an infusion of 1,500-2,000 units/hour, with adjustments based on clotting parameters. 1

Standard Heparin Protocol for Dialysis

Initial Dosing

• Loading dose: 25-30 units/kg IV bolus at the start of dialysis
• Maintenance dose: 1,500-2,000 units/hour continuous infusion

Monitoring and Adjustment

• Follow equipment manufacturer's specific recommendations when available
• Monitor the extracorporeal circuit visually for clotting
• Consider semiquantitative clotting scoring of the dialyzer and venous chamber to guide dose adjustments 2
• Laboratory monitoring is not routinely indicated for most hemodialysis patients but may be considered in select cases 2

Special Considerations

Patients with Heparin-Induced Thrombocytopenia (HIT)

For patients with HIT requiring dialysis, alternative anticoagulants should be used:

1. Acute HIT:

   • Use argatroban, danaparoid, or bivalirudin rather than other non-heparin anticoagulants 3
   • Argatroban is preferred in patients with liver dysfunction 3
   • Danaparoid has been successfully used despite its renal clearance 3

2. Subacute or Remote HIT:

   • Regional citrate is recommended rather than heparin or other non-heparin anticoagulants 3
   • Citrate acts as a regional anticoagulant and is more cost-effective than other alternatives 3

Monitoring Options

When laboratory monitoring is deemed necessary:

• Activated partial thromboplastin time (aPTT): Target 1.5-2 times normal
• Activated clotting time (ACT): For bedside monitoring
• Anti-Factor Xa assay: More specific measure of heparin activity 2

Practical Implementation

1. Preparation:

   • Confirm the correct heparin concentration before administration
   • Inspect solution for particulate matter and discoloration
   • When adding heparin to an infusion solution, invert the container at least six times to ensure adequate mixing 1

2. Administration:

   • Administer through the arterial line of the dialyzer
   • Avoid intramuscular injections due to risk of hematoma formation 1

3. Safety Monitoring:

   • Monitor platelet counts periodically
   • Check hematocrit and occult blood in stool during therapy 1
   • Be vigilant for signs of bleeding complications

Common Pitfalls and Caveats

• Overdosing: Can lead to hemorrhagic complications; careful dosing is essential
• Underdosing: May result in clotting of the dialysis circuit and reduced dialysis efficacy
• HIT development: Monitor for unexplained platelet count drops (>50% from baseline)
• Lipid effects: Long-term heparin use may affect lipid profiles; consider low molecular weight heparin in patients with dyslipidemia 4
• Alternative options: For patients with absolute contraindications to heparin, consider prostacyclin 5 or regional citrate anticoagulation

Unfractionated heparin remains the preferred anticoagulant for most dialysis patients due to its short half-life, reversibility with protamine, low cost, and extensive clinical experience 6. However, the regimen should be carefully monitored and adjusted based on the individual patient's response and risk factors for bleeding or thrombosis.