From WardWiki - Foundation Doctor Helper
Heparin, more accurately referred to an unfractionated heparin, is a parenteral anticoagulant that is monitored by its effects on APTT.
All hospitals will have a heparin infusion protocol that aids prescription. Unfractionated heparin used for the following situations:
Certain high risk situations require immediate anticoagulation such as an acutely ischaemic limb.
Adjunct to thrombolysis
A loading dose is given prior to infusion with r-TPA.
Temporary cessation of coumarin anticoagulation
Recent DVT or mechanical heart valves require continuous anticoagulation and heparin provides a means to maintain this in a much more controllable manner. No loading dose is required for patients already anticoagulated.
Heparin Induced Thrombocytopenia
HIT is a rare but serious reaction to heparin due to inappropriate activation of platelets. Heparin therapy must be stopped and urgent haematology advice sought if the following occur.
A fall in platelet count of >50% of the previous value, or the lowest count is 20–100 × 109/liter.
A fall is 30–50% or the lowest count is 10–19 × 109/liter.
A new proven thrombosis, skin necrosis (see below), or systemic reaction on warfarin