Check indication
BEFORE STARTING TREATMENT
- Check indication for use of IV unfractionated heparin in relevant guideline. Is this correct regime?
- e.g. use for post thromboembolism but not following post MI thrombolysis
- Check the following:
- no allergy or previous history of heparin-induced thrombocytopenia
- FBC (specially for baseline platelets)
- International Normalised Ratio (INR)
- APTT ratio
- U&E (to check baseline serum potassium)
- If starting a pregnant woman on IV unfractionated heparin, discuss with consultant haematologist to arrange anti-Xa monitoring
- Check need for loading dose
- advice in indication for use of IV unfractionated heparin in relevant guideline
Prescription
- Prescribe in hospital’s prescription chart
INITIATION: LOADING DOSE
Do you need loading dose?
- Weigh patient
- Give bolus dose of unfractionated heparin (1000 units/mL) 75 units/kg IV over 5 min
- If patient unfit to be weighed, give bolus dose of unfractionated heparin 5000 units (5 mL 1000 units/mL) IV over 5 min
Volume of 1000 units/mL IVUH solution for loading dose of 75 units/kg
Enter Patients Weight (kg):
MAINTENANCE: INFUSION
- Prepare solution of 500 units unfractionated heparin per mL
- take 20 mL unfractionated heparin 1000 units/mL (which therefore contains 20,000 units)
- add 20mL of sodium chloride 0.9% injection to produce a total volume of 40 mL
- start infusion dose at 18 units/kg/hr which is equivalent to 0.036 mL/kg/hr
Maintenance infusion rate of IV heparin 500 units/mL to give 18 units/kg/hr
Enter Patients Weight (kg):
MONITORING
Warn all staff members
- Check concentration of IVUH carefully to avoid risk of overdose and bleeding
- IV heparin therapy without strict monitoring carries high risk of bleeding
APPT ratio
- Check APTT ratio 4 hr (6 hr if no loading dose) after starting infusion
- 4 hr after any dose change
- Adjust rate as dictated by APTT ratio
- patients with renal impairment may have delayed clearance of heparin
- Once APTT ratio lies within target range of 2.0–3.0, check APTT once daily
APTT ratio and corresponding change in infusion rate
Enter APPTT ratio:
Overdose or bleeding
- Contact on-call haematology consultant to advise on urgent reversal of anticoagulant effect
Heparin-induced thrombocytopenia
- Check platelet count before starting heparin and then on alternate days from day 5
- if unfractionated heparin, dalteparin or any other low-molecular-weight heparin given within last 100 days, check on alternate days from day 2
- If platelet count falls by >50% during heparin therapy, suspect heparin-induced thrombocytopenia – see Heparin-induced thrombocytopenia guideline
Hyperkalaemia
- Check U&E before starting heparin
- Twice weekly if:
- IVUH likely to continue for >7 days
- patient has raised baseline serum potassium, diabetes mellitus, chronic kidney disease or acidosis, or is taking a potassium-sparing agent
HEPARIN REVERSAL
- Protamine reverses the IVUH anticoagulant effect
- protamine carries significant risk of serious adverse drug reaction
- 1 mg of protamine neutralises 80–100 units unfractionated heparin when administered within 15 min of the heparin dose
- if protamine is required more than 15 mins after heparin dose, less is needed
- 50 mg protamine sulphate is enough for most bleeds
- Report all anticoagulant related bleeding events
- Contact on-call haematology consultant for advice if necessary
© 2022 The Bedside Clinical Guidelines Partnership.
Created by University Hospital North Midlands and Keele University School of Computing and Mathematics.
Research and development team: James Mitchell, Ed de Quincey, Charles Pantin, Naveed Mustfa