When to use heparin (unfractionated heparin) drip in the Intensive Care Unit (ICU)?

From the Guidelines

Use of Heparin Drip in ICU

Use heparin drip in ICU when a patient has a high risk of thromboembolism, such as those with acute limb ischemia, pulmonary embolism, or deep vein thrombosis, and requires ongoing anticoagulation 1.

• The typical dose is an initial bolus of 80 units/kg followed by an infusion of 18 units/kg/hour, with adjustments made to maintain an activated partial thromboplastin time (aPTT) between 60-80 seconds 1.
• Monitor aPTT every 6 hours and adjust the heparin dose accordingly 1.
• Consider using a heparin protocol to guide dosing and minimize the risk of bleeding complications 1.
• The duration of the heparin drip depends on the underlying condition, but it is typically continued until the patient is stable and can be transitioned to oral anticoagulation or until the risk of thromboembolism has decreased 1.
• Important Considerations:
  • In patients with severe renal impairment, UFH is preferred due to its hepatic metabolism 1.
  • Heparin resistance may occur in critically ill patients, and monitoring anti-Xa levels may be necessary to adjust the heparin dose 1.
  • The risk of heparin-induced thrombocytopenia (HIT) should be monitored, especially in patients with a history of HIT or those receiving high doses of heparin 1.
• Special Populations:
  • In patients with cancer-associated venous thromboembolic disease, UFH may be used as an alternative to LMWH, especially in those with severe renal impairment 1.
  • In critically ill patients with COVID-19, UFH may be preferred due to its shorter half-life and easier reversibility compared to LMWH 1.

From the FDA Drug Label

When initiating treatment with Heparin Sodium Injection by continuous intravenous infusion, determine the coagulation status (aPTT, INR, platelet count) at baseline and continue to follow aPTT approximately every 4 hours and then at appropriate intervals thereafter The dosing recommendations in Table 1 are based on clinical experience be adjusted for the individual patient according to the results of suitable laboratory tests, the following dosage schedules may be used as guidelines: Table 1: Recommended Adult Full-Dose Heparin Regimens for Therapeutic Anticoagulant Effect *Based on 68 kg patient METHOD OF ADMINISTRATION FREQUENCY RECOMMENDED DOSE Continuous Intravenous Infusion Initial Dose 5,000 units by intravenous injection Continuous 20,000 to 40,000 units/24 hours in 1,000 mL of 0.9% Sodium Chloride Injection, USP (or in any compatible solution) for infusion

Use of Heparin Drip in ICU:

• Heparin drip should be used in the ICU when a patient requires therapeutic anticoagulation.
• The decision to start a heparin drip should be based on the patient's coagulation status and clinical experience.
• The recommended adult full-dose heparin regimen for therapeutic anticoagulant effect is:
  • Initial dose: 5,000 units by intravenous injection
  • Continuous infusion: 20,000 to 40,000 units/24 hours in 1,000 mL of 0.9% Sodium Chloride Injection, USP (or in any compatible solution) for infusion
• Monitoring of aPTT, INR, and platelet count is essential to adjust the heparin dose and prevent complications 2

From the Research

Indications for Heparin Drip in ICU

• Heparin drip is indicated for the initial treatment of acute pulmonary embolism or proximal deep vein thrombosis in ICU patients 3
• It is also used for thromboprophylaxis in ICU patients who are at high risk of thrombotic events due to immobilization, mechanical ventilation, and central catheters 4
• The use of heparin drip is recommended for patients with high risk of bleeding, where mechanical thromboprophylaxis can be used as an alternative 4

Dosage and Administration

• The initial dose of heparin is 5000 units as an intravenous bolus, followed by a maintenance dose of 30,000-40,000 units per 24 hours by continuous intravenous infusion 3
• The dosage of heparin can be adjusted based on the patient's activated partial thromboplastin time (APTT) to achieve an adequate anticoagulant response 3
• A study found that prophylactic dosing of heparin 3 times/day versus twice/day was not associated with differences in new venous thromboembolism or safety outcomes in critically ill patients 5

Monitoring and Duration of Therapy

• The APTT should be monitored regularly to adjust the heparin dose and prevent bleeding complications 3
• Heparin therapy is typically continued for 7-10 days, overlapped with warfarin sodium during the last 4-5 days 3
• The duration of heparin therapy may vary depending on the patient's condition and the presence of bleeding complications 6

Special Considerations

• ICU patients are at high risk of thrombotic events, and heparin drip should be used in conjunction with other prophylactic measures such as mechanical thromboprophylaxis 4
• The use of heparin drip should be individualized based on the patient's risk factors for thrombosis and bleeding 7
• Regular ultrasound screening should be performed to diagnose deep vein thrombosis in ICU patients 7