Indications:

• an infusion of unfractionated heparin should be considered if immediate anticoagulation is required or if urgent reversal may be needed e.g. known potential bleeding site.
• unfractionated heparin should be used if the creatinine clearance less than 30ml/min if surgery is required within 24 hours.

When prescribing unfractionated heparin use the NHS Lothian Adult Heparin Infusion Chart (available on the front page of the intranet).

http://intranet.lothian.scot.nhs.uk/Directory/Haematology/policy/Documents/Heparin%20Infusion%20Chart.pdf

This chart has been designed for use in a patient with standard bleeding risk, so consider if a bolus of heparin is required prior to starting the infusion. Also consider carefully the infusion starting rate if the patient has a risk of bleeding. If in doubt ask the on call duty haematologist.

Please note that in NHS Lothian UFH is available in a ready-made concentration of 1000 units/ml. Prescribe as “heparin 1000 units/ml”. Do not dilute this preparation.

• Use the ready-made concentration of heparin 1000units/ml
• This concentration must not be diluted
• For a patient of average weight, with normal renal function and no bleeding risk, give a loading dose of 5000 units (5ml)
• Start the infusion at a rate of 1200 units (1.2ml)/hr
• Check the APTTr 6 hourly until stable in the therapeutic range and adjust rate to achieve a therapeutic range of 2.0-3.0
• Monitor platelets on a daily basis

As the half-life of unfractionated heparin is about 1 hour, it is usually sufficient to stop the heparin infusion without administration of a specific reversal agent. If bleeding is severe, consider protamine sulphate (1mg for every 100 units heparin given in previous hour). Give slowly at rate not exceeding 5 mg/min, maximum single dose of 50mg. The anticoagulant effect of LMWH dalteparin can be partially reversed by protamine sulphate. One mg of protamine sulphate inhibits the effect of 100 units (anti-Xa) of dalteparin. The usual maximum dose is 50 mg given by slow IV injection at a rate not exceeding 5 mg per minute.

Note - there is a risk of anaphylaxis with protamine administration.