Unfractionated heparin
Background
- Binds to and activates antithrombin which in turns inactivates factor Xa and thrombin
- Anticoagulation effect lasts up to 3hr after stopping infusion
- Must give IV (not subq) for acute thromboembolic disease
- Safe in pregnancy
- Unpredictable anticoagulation effect
- Must monitor w/ PTT; therapeutic range is 1.5-2.5x normal value
- 33% of pts develop some form of bleeding complication; 2-6% develop major bleeding
Risk Factors for Major Bleeding Complication
- Recent surgery or trauma
- Renal failure
- Alcoholism
- Malignancy
- Liver failure
- Concurrent use of warfarin, fibrinolytics, steroids, or antiplatelet drugs
Treatment
Complications
- Bleeding
- Treatment
- Managed according to clinical severity, NOT PTT value
- Heparin-associated bleeding is not always reflected by a supratherapeutic PTT
- Stop transfusion
- Observation alone may be appropriate in less severe cases
- Protamine
- Only indicated for major bleeding (0.2% of pts develop severe anaphylaxis)
- Give 1mg IV for every 100 units of UFH infused in the prior 3hr
- Give slowly over 1-3min; do not exceed 50mg in any 10 minute period
- Because half-life is short (7 min) may require second treatment
- Massive bleed
- Cryoprecipitate (10 U IV), then FFP (& platelets, aminocaproic acid infusion if nec)
- Managed according to clinical severity, NOT PTT value
- Treatment
- Heparin-Induced Thrombocytopenia
See Also
Source
Tintinalli