General Principles

Anticoagulation in critically ill patients is a challenging issue, with patients at risk of bleeding diatheses as well as hypercoagulable states.  Often a single patient will move through a state with a high risk of bleeding (including surgical sites) to one of high risk of developing venous stasis and thrombosis.  The decision to administer anticoagulation is often based on a relative risk-benefit assessment.


Where anticoagulants are contra-indicated, alternative methods should be employed to prevent venous stasis in the lower limbs (graded compression stockings and sequential calf compressions), although it is unclear as to whether these confer adequate protection against thrombosis and embolism.


As a general rule for therapeutic anticoagulation heparin infusions should be used to effect anticoagulation, titrated intravenously to a therapeutic APTT.  Low molecular weight heparins require measurement of anti-factor Xa to quantify effect, and are more difficult to reverse than unfractionated heparin.


Prophylactic Use of Heparin

In most instances low molecular weight heparin (Clexane 40mg sc od) is considered as safe, and in some instances marginally superior, (eg: orthopaedic patient populations) to unfractionated heparin (5000U sc od).

DVT prophylaxis using Clexane (Enoxaparin) 40mg sc od should be universal in intensive care patients with exceptions listed below:

    • Patients with active bleeding / coagulopathy

    • Thrombocytopaenia

    • Patients that are fully anticoagulated therapeutically (ie: with warfarin)

    • Intracranial haemorrhage (primary or following head injury)

    • Following eye surgery

    • DVT prophylaxis in patients following neurosurgery is relatively safe (<1% risk of significant haemorrhage) but should be discussed with the neurosurgical team prior to use.

    • Heparin Induced thrombocytopenia or other heparin hypersensitivity


Page last reviewed: 09 May 2014