When to use heparin (unfractionated heparin) infusion in the Intensive Care Unit (ICU) based on Evidence-Based Medicine (EBM)?

From the Guidelines

Use of Heparin Infusion in ICU

Heparin infusion should be used in the ICU for patients requiring anticoagulation, particularly those with acute venous thromboembolism, pulmonary embolism, or atrial fibrillation with high risk of stroke 1. The recommended initial dose is typically a 500-1000 units IV bolus, followed by a continuous infusion of 12-18 units/kg/hour, with a maximum dose of 1000 units/hour.

Monitoring and Adjustment

Monitoring of aPTT levels every 6 hours is crucial, and the dose should be adjusted to maintain a therapeutic range of 60-80 seconds 1. However, in patients with a hyperinflammatory state, such as those with COVID-19, anti-Xa assay may be more suitable for monitoring heparin therapy due to its lesser dependence on pre-analytical conditions and laboratory interference 1. The target anti-Xa level for therapeutic dose heparin is 0.5-0.7 IU/mL.

Special Considerations

In patients with renal insufficiency, consider using a lower dose and closely monitoring aPTT levels or anti-Xa levels 1. For patients with severe renal dysfunction, heparin may be preferred due to its hepatic metabolism, but careful monitoring is necessary to avoid overdose.

Duration of Therapy

The duration of heparin drip depends on the underlying condition but typically ranges from 3-14 days. It is essential to closely monitor patients for signs of bleeding and adjust the dose accordingly.

Key Points

• Use heparin infusion for anticoagulation in ICU patients with specific conditions.
• Monitor aPTT or anti-Xa levels regularly and adjust the dose as needed.
• Consider special patient populations, such as those with renal insufficiency or hyperinflammatory states.
• Duration of therapy varies based on the underlying condition.

From the Research

Indications for Heparin Infusion in ICU

• Heparin infusion is indicated for the initial treatment of acute pulmonary embolism or proximal deep vein thrombosis in ICU patients, as it prevents recurrent venous thromboembolism 2.
• The primary objective of heparin therapy is to achieve an adequate anticoagulant response, which is associated with a low frequency of recurrent venous thromboembolism 2.
• Heparin infusion is also used for prophylaxis in critically ill patients, as venous thromboembolism is a common and potentially fatal complication in the ICU 3.

Dosage and Administration

• The recommended dosage of heparin is an initial intravenous bolus of 5000 units, followed by a maintenance dose of 30,000-40,000 units per 24 hours by continuous intravenous infusion 2.
• The dosage of heparin may vary depending on the patient's risk factors and the presence of bleeding or thrombotic complications 4, 5.
• The use of prophylactic heparin dosing strategies, such as 5000 units twice or three times a day, has been evaluated in critically ill patients, but no significant differences in outcomes were observed between the two dosing regimens 4.

Risk Factors and Contraindications

• Critically ill patients have special characteristics that increase the risk for venous thromboembolism, including sepsis, acute brain injury, major trauma, and COVID-19 3.
• Patients with renal impairment, obesity, or those who are critically ill require individual approaches to prophylaxis 5.
• The presence of bleeding risk factors, such as thrombocytopenia or recent surgery, may contraindicate the use of heparin infusion 3, 5.

Monitoring and Duration of Therapy

• The activated partial thromboplastin time (APTT) should be monitored regularly to ensure that the patient is receiving an adequate anticoagulant response 2.
• Heparin infusion is typically continued for 7-10 days, overlapped with warfarin sodium during the last 4-5 days 2.
• The duration of therapy may vary depending on the patient's underlying condition and the presence of complications 6.