Anticoagulants are chemical reagents or substances that can prevent blood from clotting. They can prevent erythropoietin from thickening the blood, treat phlebitis, and prevent blood clots from forming in veins. There are many common anticoagulants, except for ethylenediaminetetraacetic acid , Heparin, potassium oxalate, sodium fluoride and sodium citrate. Sodium citrate is also known as trisodium citrate, so how much do we know about sodium citrate anticoagulation? Next, Desheng will give you a brief understanding of sodium citrate related knowledge.

Sodium Citrate/Trisodium Citrate

There are no more than two coagulation pathways: the intrinsic coagulation pathway and the exogenous coagulation pathway. In these two coagulation pathways, the two important factors involved in the coagulation mechanism are thrombin and ionized calcium.

Ca 2+ is needed in the endogenous coagulation pathway; the exogenous coagulation pathway mainly depends on thrombin. So we can achieve the anticoagulant effect as long as we get one of them. Citrate anticoagulation is to reduce the concentration of Ca 2 + in the blood of the extracorporeal circuit to achieve anticoagulation.

The principle of sodium citrate anticoagulation:

Sodium citrate anticoagulation mainly uses sodium citrate to chelate calcium ions in the extracorporeal blood into citrate chelated calcium, and then citrate chelate calcium enters the body and passes through the liver, skeletal muscle, and kidney cortex. Metabolism, decomposed into HCO3-+Ca2+ etc. after the tricarboxylic acid cycle metabolism. Sodium citrate achieves local anticoagulation of the in-line filter through calcium ion chelation during blood purification.

Application of sodium citrate:

Citrate is mainly used for hemostasis testing and the determination of erythrocyte sedimentation rate. Because of its low toxicity, it is also used in blood transfusion maintenance solutions. The anticoagulant mechanism is that citrate forms a soluble chelate with calcium ions in the blood to prevent blood from clotting. The reaction formula is Na3C6H5O7+Ca2+→CaC6H5+3Na+. Its salt is mainly sodium salt.

Sodium citrate has Na3C6H5O7ZH?5O and 2Na3C6H5O7+1H2O2 crystals. The former is usually used to prepare a blood solution of 0.129 mol/L (3.8%) or 0.109mol/L (3.2%), and use it with blood at a ratio of 1:9. For patients who are used to monitor oral warfarin and other anticoagulant therapy, the concentration of sodium citrate (3.2% or 3.8%) used in the determination of PT and APTT should not be changed at will, because it may affect the international normalized ratio (INR). Generally, the INP value of sodium citrate with a concentration of 0.129mol/L is higher than that with a concentration of 0.109mol/L. In addition, for thromboplastin reagents from different sources, the clotting time of the plasma of the same normal person or patient can vary greatly . Therefore, the source of the thromboplastin reagent used in each laboratory should be as constant as possible, and the preparation method should be standardized, otherwise the clotting time will be prolonged or shortened, or the normal value will be irregular. Conditional laboratories can use buffered anticoagulants, which are more suitable for analysis of specimens after cryopreservation. The function of the buffer is to maintain a constant pH of the plasma and prevent the inactivation of volatile factors.

Relative contraindications for sodium citrate anticoagulation:

1. Patients who are allergic to sodium citrate anticoagulant,

2. Patients with severe liver dysfunction (TB>2 times the normal value),

3. Hypoxemia (arterial partial pressure of oxygen <60mmHg) and/or insufficient tissue perfusion (high-dose vasoactive drugs still use blood pressure <90/60mmHg),

4. Metabolic alkalosis,

5. Patients with hyperlactic acidemia (LAC>4mmol/l),

6. Hypernatremia.