Introduction:
Extracorporeal blood purification techniques have become a well-established part of routine practice in intensive therapy units. Ensuring appropriate anticoagulation to prevent the clotting of the circuit is the major concern while applying these techniques.

Aim:
The aim of this paper is to present methods of systemic anticoagulation which are currently used in continuous extracorporeal blood purification techniques.

Material and methods:
This work is based on the available literature and the experience of the authors.

Results and discussion:
The prevention of clotting in the extracorporeal circuit may be achieved through regional or systemic anticoagulation. Systemic anticoagulation is usually achieved by administration of unfractionated heparin. The most common complications include bleeding; additionally, there is a risk of type II thrombocytopenia occurring. Systemic anticoagulation may also be provided through administration of low molecular weight heparins. Some research papers have discussed the use of thrombin antagonists (argatroban, bivalirudin) and heparinoids (danaparoid, fondaparinux), as well as platelet inhibitors as systemic anticoagulants. It is also possible to conduct extracorporeal blood purification without anticoagulation.

Conclusions:
The introduction of continuous extracorporeal blood purification techniques into everyday practice of intensive care units has brought many unquestioned benefits to the patients treated in this setting. On the other hand, it means that doctors need to show an in-depth knowledge of the anticoagulation methods. Despite the wider use of regional anticoagulation during continuous renal replacement therapy, systemic anticoagulation is still important. This is especially when therapies with high blood flow are performed and contraindications to citrate use are present.