Membrane plasmapheresis

The term “plasmapheresis” comes from the Greek words “plasma” and “apheresis”, which can literally be translated as “separate plasma”. Plasmapheresis in medicine is called the procedure of extracorporeal purification of blood from toxic and ballast compounds. Membrane, or filtration, plasmapheresis differs from other types of this procedure in the way it is carried out: the removal of toxic substances from the blood is carried out by filtering the plasma on special devices with plasma filters.

Principle of plasmapheresis

The principle of blood purification by filtering on the apparatus (Hemofeniks, Hemos-PF) is that the blood withdrawn from the vessels is separated using special plasma filters into blood cells (erythrocytes, leukocytes, platelets) and plasma. After separation, blood cells return to the patient’s bloodstream, which is why membrane plasmapheresis is called “blood cell washing”. The filtered plasma is collected in a container and disposed of after the procedure; the deficit in circulating blood volume, if necessary, is replenished with plasma-substituting solutions.

Plasmapheresis is an auxiliary therapeutic method, which is used in medical treatment only together with the main areas of treatment. The benefits of blood filtration are detoxification of the body, reflex stimulation of the cardiovascular system, increased immunity, and improved rheological properties of blood. Feedback from patients about the results of the procedure indicates an improvement in their well-being.

Detoxification of the body

The plasma filter of the device for membrane plasmapheresis is a semi-permeable membrane made of porous fibers with a diameter of 10 microns, between which there are pores with a diameter of 5 microns. Such a filter retains blood cells, but freely passes the liquid blood fraction along with harmful substances dissolved in it (toxic compounds, antigens of microorganisms, pathological immune complexes).

Stimulation of the cardiovascular system

A decrease in the volume of circulating blood reflexively increases the heart rate, as a result of which the time of one complete circle of blood circulation is reduced. Toxic substances remaining in them are washed out of the tissues faster, which during the next plasmapheresis procedure facilitates their removal from the body. If a large amount of plasma is removed during the procedure, its deficiency is restored using plasma-substituting solutions.

Increased immunity

Passing through the plasma filter, immune cells come into contact with a substance foreign to the human body. As a result of such contact, the immune system begins to work hard – a state of “tense immunity” arises (as after vaccination). Replacement of part of the plasma with donor plasma substitutes additionally stimulates the patient’s immunity.

Improved blood flow

The improvement in blood flow does not come from the procedure itself, but from the flow of interstitial fluid into the bloodstream after it. Hemodilution occurs – blood thinning due to protein-free solutions.

If necessary, before the manipulation or during it, patients are given heparin (70-150 U/kg) liquid, which helps to improve the rheological properties of the blood. In addition, plasma-substituting solutions administered after a session to compensate for the lack of circulating blood volume also thin it, thereby improving microcirculation in tissues.

Advantages and disadvantages

The procedure of membrane plasmapheresis on modern devices has a number of advantages over centrifugal and other types of blood purification:

• one of them is the use of a single-needle scheme, which provides patients with comfort during manipulation;
• blood purification on the apparatus occurs continuously, so the manipulation time is reduced in comparison with its other types;
• if sterile disposable contours (sets) are used for the procedure, this minimizes the risk of infection of the patient with hematogenous infections;
• the filtration process is carried out under constant computer monitoring, which guarantees its safety.

However, one should not overestimate the possibilities of plasmapheresis: it only reduces the concentration of certain harmful compounds in the blood, and does not prevent their formation. Since it does not fight the causes that cause an increase in the concentration of toxic substances, therefore, the method does not “work” on its own.

Together with harmful low molecular weight compounds (amino acids, electrolytes, acids, alkalis, salts, some enzymes).

In some cases, autoimmune reactions that occur after the procedure are excessive and can provoke an exacerbation of autoimmune processes, therefore, in autoimmune pathologies, control immunological studies should be carried out regularly.

Strict indications are required for the procedure. The expected benefit of plasmapheresis should greatly outweigh the risk of possible complications after it.

Indications for the procedure

Indications for therapeutic filtration plasmapheresis, according to the recommendations of the World Association for Hemapheresis, are more than 200 different diseases and pathological conditions. These include:

• exogenous and endogenous intoxications of various etiologies (food poisoning, overdose of drugs, alcohol, drugs, post-chemotherapy and radiation therapy, osteomyelitis, severe infections, paraneoplastic intoxications);
• autoimmune, allergic and dermatological diseases (rheumatoid arthritis, multiple sclerosis, scleroderma, lupus erythematosus, bronchial asthma, hay fever, allergies, dermatomyositis, burn disease, psoriasis);
• pregnancy pathologies (Rhesus conflicts, preeclampsia of pregnant women, nephropathy, fetoplacental insufficiency);
• pathology of the respiratory system (pneumonia, pneumonitis, hemosiderosis, Wegener’s granulomatosis, alveolitis);
• diseases of the digestive system (inflammatory and erosive and ulcerative processes, hepatitis, hepatosis, cirrhosis);
• nephrological diseases (pyelonephritis, glomerulonephritis, renal failure);
• pathologies of the central nervous system and sensory organs (neuroinfections, ophthalmopathy, retinopathy, uveitis);
• diseases of the cardiovascular system (ischemia, angina pectoris, cardiomyopathy, myocarditis, post-infarction conditions, hypercholesterolemia, atherosclerosis);
• endocrine pathologies (diabetes mellitus, Addison’s disease, hyperthyroidism);
• blood diseases (monoclonal gammopathy, thrombocytopenic purpura, macroglobulinemia, myeloma).

Preventive plasmapheresis once a year is recommended for people working in hazardous industries, as well as before the season of colds – for people with reduced immunity.

Contraindications for plasmapheresis

Despite the fact that membrane plasmapheresis is a useful procedure for many diseases, it still has its contraindications. Distinguish:

1. Relative, the elimination of which allows for membrane plasmapheresis.
2. Absolute, which make the blood purification procedure by filtering on membranes impossible.

Relative contraindications to performing filtration blood purification are:

• high risk of bleeding, for example, with peptic ulcer of the stomach and duodenum;
• acute infections;
• menstrual bleeding;
• low levels of blood proteins;
• severe anemia;
• edema syndrome;
• shock conditions;
• hypotension.

Absolute contraindications include a decrease in blood coagulation, which provokes recurrent bleeding, trauma to internal organs, mental illness, heart and liver failure, arrhythmias, and stroke.

Preparing for the procedure

In preparation for plasmapheresis, the patient undergoes a whole range of laboratory and instrumental studies, which includes: a general and biochemical detailed blood test, a coagulogram, a study for hepatitis B and C, HIV infection, syphilis, blood glucose levels, tonometry, electrocardiography. Consultations of the therapist and the cardiologist are also obligatory.

A general blood test shows the number and ratio of blood cells and the rate of blood sedimentation. The coagulogram determines the time of blood clotting, the tendency to thrombosis or bleeding. The list of biochemical parameters is established depending on the pathology, which is the basis for plasmapheresis, and subsequently monitored after each procedure.

Half an hour or an hour before the start of the session, the patient needs to have a snack to avoid fainting. The day before the procedure, it is forbidden to take alcohol, immediately before it – to smoke. Also, do not exhaust yourself with heavy physical work or sports loads.

Carrying out blood purification

The patient is connected to a device that, in addition to purifying the blood, controls the pulse, blood pressure, respiration, and the level of oxygen in the blood.

In most cases, plasmapheresis is well tolerated by patients. Sometimes they note mild nausea, dizziness, weakness, drowsiness immediately after the procedure.

After the end of the procedure, the patient needs rest: for an hour he needs to lie down in a horizontal position in order to replenish the volume of circulating blood and redistribute it in the body. During the entire course of treatment, patients should refrain from visiting baths, hot baths, and exposure to the open rays of the sun.

Sensitive people with severe side effects (dizziness, severe weakness) may be recommended for plasmapheresis in stationary conditions.

The duration of one procedure can be from 60 to 90 minutes. In one session, up to 25% of the blood plasma can be withdrawn from the patient’s bloodstream. The cost of one session depends on the form of ownership of the clinic and ranges from 3 to 8 thousand rubles. At the same time, the city of holding (Moscow, St. Petersburg or Omsk) usually does not affect the price of manipulation. The number of sessions that a patient needs depends on the disease that served as an indication for plasmapheresis. For example, 3-5 sessions are prescribed for allergic pathologies, 8-10 sessions for severe psoriasis.

Complications after plasmapheresis

After the plasmapheresis procedure, some patients may develop various complications. These include allergic reactions, pulmonary edema, bleeding, phlebitis of the vein to which the system is connected, and a drop in blood pressure. Violation of the rules of asepsis and antisepsis during manipulation can lead to infection of patients with viral hepatitis, HIV infection and other infectious diseases with hematogenous transmission.

In one in five thousand patients who have undergone a course of plasmapheresis, complications are so pronounced that they cause death.

Plasmapheresis is a fairly effective therapeutic and prophylactic procedure. It improves the quality of life of long-term ill patients, as well as prevents the development of severe complications in them. However, it must be understood that it is not advisable to use it instead of the main treatment of the disease: its effectiveness is reduced significantly.