For Doctors

Plasmapheresis (from the Greek plasma — the liquid part of blood; apheresis — removal) is a form of extracorporeal therapy aimed at removing dialysable blood components while preserving its cellular elements. The method is used in the combined treatment of more than 200 conditions in whose aetiology and pathogenesis exogenous or endogenous intoxication, or the accumulation of metabolic products, plays a leading role.

The SAN Centre for Detoxification and Efferent Therapy uses continuous, or flow-through, membrane plasmapheresis — a method that is safe, comfortable and atraumatic for the cellular elements of blood. As prescribed by the physician, membrane plasmapheresis may be combined with parallel extracorporeal pharmacotherapy, laser immunocorrection, ultraviolet irradiation or ozonation of the blood.

Membrane plasmapheresis is performed on a dedicated device (for example, the AMPld TT Hemofenix) using single-use plasma filters, an extracorporeal circuit (a disposable set of tubing lines) and an individual set of plasma-substituting solutions and anticoagulants, in the intensive care unit of the VitaCentre clinic.

During plasmapheresis, alongside detoxification, the following processes take place:

Relief of the body’s excretory organs and systems.

Cleansing of the plasma membrane of the cellular elements of blood.

An increase in the elasticity coefficient of blood cell membranes.

Improvement of blood rheology, microcirculation and systemic haemodynamics.

Stimulation of immunogenesis.

Unblocking of receptors and an increase in their functional activity in haematopoietic, phagocytic and immunocompetent cells.

Normalisation of oxygen metabolism and tissue respiration.

Stimulation of antithrombin activity and fibrinolysis.

Normalisation of the permeability of the basement membrane of the renal glomeruli, a reduction in proteinuria and normalisation of the proteinogram.

An antihypoxic effect, which has been clinically proven.

Protection against the effects of end products of lipid peroxidation and intoxication products.

Normalisation of the hormonal function of the hypothalamus, the pituitary gland, the adrenal glands and the ovarian system.

VASCULAR ACCESS — the cubital veins

THE VOLUME of plasma removed in a single session is calculated by the unit’s intensive care physician on the basis of body weight, haematocrit and biochemical parameters. The volume of plasma removed is usually between 500 ml and 700 ml.

THE VOLUME of blood in the extracorporeal circuit is 60–120 ml, which the patient does not feel at all. After the procedure, the entire cell mass is returned from the line to the patient’s bloodstream.

MODE OF DELIVERY — isovolaemic; there is no blood loss.

AGENTS USED: anticoagulants — Na citrate; heparin (5,000–10,000 units);

PLASMA REPLACEMENT:

• Crystalloids (Ringer’s solution, saline);
• Dextrans (rheopolyglucin);
• HES solutions — hydroxyethyl starch (Voluven);
• Protein solutions (albumin);
• Marked organic changes in the cardiovascular system and the CNS;
• unstable haemodynamics
• Bleeding;
• Absence of venous access;
• phlebitis of the peripheral veins in the acute stage;
• Allergic reactions to anticoagulants, colloid and protein preparations;
• Anaemia (Hb<90 g/l); thrombocytopenia (platelets <100 × 10⁹/l);
• Hypoproteinaemia (total protein <65 g/l);
• Hypocoagulation;

Plasmapheresis in children: for children weighing more than 40 kg, with normal protein levels and a normal haemostasiogram, the procedure is performed as in adults. For children of lower weight it is used only on clear indications (acute poisoning); for those weighing less than 10 kg the procedure is performed by the syringe method in an inpatient setting.

The coagulation system during plasmapheresis. Replacing the removed plasma with saline solutions, dextrans and/or albumin lowers the patient’s clotting factors. The extent of that reduction depends on the volume of apheresis. After one to three sessions patients show no haemostatic disturbances unless they had severe thrombocytopenia or a bleeding tendency beforehand. For such patients replacement is carried out mainly with fresh frozen plasma (FFP). In patients with normal synthesis it takes 24–48 hours for clotting factors to return to their baseline level, which the efferent therapy physician allows for when planning the course.

The concentration of all plasma components falls in proportion to the volume of plasmapheresis, except for those contained in the replacement solutions. This may affect drug activity as follows:

removal of drugs together with the plasma may lower their concentration below the therapeutic level (examples of such drugs are digitoxin, cyclophosphamide, prednisolone and vibramycin);

removal of plasma components may disturb the metabolism or activity of medicines. (For example, removing antibodies to acetylcholine receptors can substantially increase the activity of anticholinesterase mediators. Conversely, plasmapheresis removes pseudocholinesterase along with the plasma, so the use of neuromuscular blockers leads to prolonged blockade, even for several days after the last session.)

Plasmapheresis is extremely effective when performed before a course of medication is prescribed, during remission.

Plasmapheresis is most often the method of choice in fulminant disease and in a torpid course (a sluggish process that does not respond to drug therapy). PLEASE NOTE: performing plasmapheresis at the peak of effective drug therapy is inadvisable. It is performed in cases of intoxication (overdose) with the active agent, as a single session.

A proven clinical effect and a guaranteed improvement in laboratory values are achieved by removing 1–1.5 CPV (circulating plasma volume). That is 2–4 plasmapheresis sessions. A course may reach 7–8 sessions. The number can be reduced by combining plasmapheresis with haemosorption and/or infusion therapy. The interval between procedures is 1–3 days; between courses, at least 1.5–2 months. SINGLE procedures are performed for preventive purposes (for example, during a seasonal flare-up), in acute exogenous (uncomplicated) poisoning, after courses of highly toxic drugs (biltricide, for instance), and before the planned start of treatment (in venereology, for example).

LABORATORY TESTS REQUIRED FOR PLASMAPHERESIS:

Mandatory:

• Full blood count;
• Total protein;
• Albumin;

PTI (prothrombin index);

Fibrinogen;

In addition — every diagnostically and pathogenetically significant parameter for the individual patient. During a long course of plasmapheresis the mandatory parameters are checked after the third session, or after apheresis of more than 1.5 CPV. Two days after the course ends, a clinical and laboratory examination is carried out to assess how the values have changed.

INDICATIONS FOR OUTPATIENT PLASMAPHERESIS:

• No response to therapy;
• Reducing the volume and increasing the effectiveness of standard drug therapy;
• Lowering tolerance to medicines;
• The introductory phase of a planned course of immunosuppressive therapy;
• Hypercholesterolaemia with a high level of low-density lipoproteins;
• Drug-induced hepatitis with hyperenzymaemia, eosinophilia and leukopenia;
• Raised AST, ALT, ALP and bilirubin in the blood plasma;
• Polyvalent allergy;
• A long-standing history of infection;
• Refractoriness to antihypertensive drugs;
• Hypercoagulation (blood hyperviscosity);
• Contraindications or tolerance to corticosteroids and/or anticholinesterase drugs;
• Prevention of gestosis;
• Autoimmune disorders (including APS, anti-hCG and others);
• Sympathoadrenal crises (raised blood pressure, changes in heart rate, vomiting, polyuria);
• Hot flushes, sleep disturbance, irritability, weakness, sweating;
• Refractory skin itching;