The correct option is Heparin.
Explanation
Haemodialysis is a medical procedure used to filter waste products and excess fluid from the blood when the kidneys are compromised. During this process, blood is removed from the body and circulated through an external machine (dialyzer). Contact between blood and the artificial surfaces of the tubing and filter triggers the coagulation cascade, leading to potential clot formation.
To maintain blood fluidity within the extracorporeal circuit, an anticoagulant is essential.
- Heparin Heparin: Correct. Heparin is a potent anticoagulant naturally produced by mast cells and basophils. In the context of haemodialysis, it is added to the blood as it enters the dialysis machine to prevent coagulation. It works by activating antithrombin III, which inhibits thrombin and other clotting factors.
- Warfarin Warfarin: Incorrect. Warfarin is an oral anticoagulant used for the long-term prevention of thromboembolic events (such as deep vein thrombosis or stroke). It acts by inhibiting Vitamin K-dependent synthesis of clotting factors and is not used for immediate anticoagulation during dialysis sessions.
- Renin Renin: Incorrect. Renin is an enzyme secreted by the juxtaglomerular cells of the kidney. It regulates blood pressure and electrolyte balance through the Renin-Angiotensin-Aldosterone System (RAAS) and has no role in preventing blood clotting.
- Insulin Insulin: Incorrect. Insulin is a hormone secreted by the beta cells of the pancreas. Its primary function is the regulation of blood glucose levels.
Key Takeaway: Heparin is the standard anticoagulant agent used to prevent blood clotting within the artificial kidney (dialyzer) during haemodialysis.