What is Blood Purification

Blood purification refers to the process that leads patient's blood outside the body, removes some pathogenic substances through purification equipment, and purifies the blood so as to achieve the goal of treating kidney diseases.

Blood purification includes hemodialysis, blood filtration, blood perfusion, plasma exchange, immunoadsorption and biological filtration, etc.

Function of blood purification

Hemodialysis-removing the harmful micromolecular substances in the blood.

Blood filtration-removing the micromolecular substances, medium molecular substances and macromolecular substances.

Immunoadsorption-removing most of the pathogenic antibody and immune complex.

Plasma exchange-reducing the harmful substances in blood plasma, and removing the macromolecular protein in patient's body, such as heterologous protein, allergen, autoantibodies, water-soluble drugs, poisons and so on.

Blood perfusion-introducing patient's blood into perfusion apparatus equipped with solid absorbent to clear some exogenous or endogenous toxins, and then put the purified blood back to the body. This is mainly used for rescuing overdoses and poisoning. The most common adsorbent is activated carbon and resin.

Schema of Blood Purification

Preparations for Blood Purification

Firstly, the preparation of the dialysis equipments.

The dialyzer is where the interchange of materials happens, and it is mastered by the nurses. Open the machine, and dialysis begins when all the indexes become normal. Equipments also include dialysis water system, dialysis catheter, puncture needle, and dialysate.

Secondly, the preparation of the medicines.

Dialysis medicines, such as physiological saline, heparin, 5% sodium bicarbonate, first-aid medications, hypertonic glucose injection, 10% calcium gluconate, dexamethasone and dialysate.

Finally, preparation of the patient.

Patient mainly needs to make preparations for vascular access. Pay attention to the possible changes, whether the catheter has slipped, bleeding, embolism, or infection and keep the catheter clean and asepsis. Besides, the dietary nutrition is also important, and patient need to arrange a proper diet according to the doctor's advice. Keep relaxed and do not be nervous or stressful.

Differences between Blood Purification and Traditional Dialysis

Dialysis is primarily used to provide an artificial replacement for lost kidney function due to renal failure. During this process, a needle is inserted into your arm through a special access point. Your blood then flows through the needle and tubing to a machine called a dialyzer, which filters your blood a few ounces at a time. The filtered blood is returned to your body through another tube and needle.

Traditional dialysis

It can only filtrate micro-molecular harmful substances, such as glucose, mineral salt, uric acid and amino acid of the blood. However, it cannot eliminate moderate molecular harmful substance and macro-molecular harmful substance in the blood.

Blood purification-innovative dialysis

Blood purification includes hemodialysis, blood filtration, blood perfusion, plasma exchange, immunoadsorption and biological filtration, etc. This technique can eliminate more harmful substances in blood, so blood will be relatively cleaner.

Continuous Blood Purification Therapy

Continuous Renal Replacement Therapy (CRRT) is any extracorporeal blood purification designed to substitute for impaired renal function over an extended period, and intended to be applied for up to 24 hours a day. This technology is one part of immunoadsorption-focused blood purification in Peking Tung Shin Tang Chinese Medical Hospital.

1. Continuous Blood Purification Therapy has been commonly used in our hospital.

● Continuous Vessels (Arteries)- Venous Hemofiltration(CV(A)VH)-mainly used to remove excessive fluid and bigger molecular material.

● Continuous Vessels (Arteries)- Venous Hemodialysis (CV(A)VHD)-mainly used for patients need remove large amount of small molecular material in high catabolism.

●Continuous Vessels (Arteries)- Venous Hemodialysis and Filtration (CV(A)VHDF)-mainly used to remove inflammatory mediators and midium and micro-molecular substances. It is suitable for patients in acute inflammatory reaction stage of renal fibrosis.

2. The features of Continuous Blood Purification Therapy.

■ Effect on hemodynamics.

Compared with traditional dialysis, the prominent advantage of CRRT is to maintain stable mean arterial pressure and effective renal blood perfusion.

■ Effect on intracranial pressure.

Acute encephaledema caused by various reasons is often accompanied by Acute Renal Failure. Giving conventional dialysis treatment is very likely to cause imbalance syndrome and aggravate encephaledema. CRRT can maintain the stableness of intracranial pressure and ensure good cerebral perfusion.

■ Compared with traditional dialysis, CRRT can control azotemia level continuously and steadily.

■ In cases of water, electrolyte, acid-base balance, and severe water and sodium retention accompanied by obvious organ edema, CRRT can remove water and sodium steadily and effectively without changes of osmotic pressure. It can remove tissue edema effectively, strengthen cardiac muscle contraction and remit pulmonary edema. It can also improve the function of the main organs such as heart, lung, liver, kidney, the stomach and intestine, etc.