Hemodilution and blood substitution operations
Last reviewed: 23.04.2024
All iLive content is medically reviewed or fact checked to ensure as much factual accuracy as possible.
We have strict sourcing guidelines and only link to reputable media sites, academic research institutions and, whenever possible, medically peer reviewed studies. Note that the numbers in parentheses ([1], [2], etc.) are clickable links to these studies.
If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please select it and press Ctrl + Enter.
Blood dilution (hemodilution) to reduce the concentration of toxic substances in it has long been used in practical medicine. This purpose is served by water loading (abundant drinking) and parenteral administration of water-electrolyte and plasma-substituting solutions. The latter are especially valuable for acute poisoning, since they allow to restore bcc simultaneously and to create conditions for effective stimulation of diuresis simultaneously with hemodilution. Blood substitution operation (hemapheresis).
General characteristics
The main curative factors of this procedure, which consist in simultaneously conducted and equal in volume of bloodletting and blood transfusion, include the following detoxification, depurational, substitutional and general biological.
The detoxification factor is based on the possible removal of various toxic substances from the patient's blood. In clinical practice, there is a real opportunity to perform only a partial blood substitution operation (OLC) in a volume of 1.5-3 L, while for a near complete (95%) replacement of the patient's blood, at least 15 liters of donor blood must be poured, the amount of 3 times the average BCC.
This circumstance significantly reduces the effectiveness of the OLC as a method of detoxification, since it allows you to remove from the blood no more than 15% of the toxicant.
The depurative effect of the blood substitution operation is to free the organism from large-molecule compounds (free plasma hemoglobin, myoglobin, etc.), which fundamentally distinguishes this method of detoxification from dialysis, in which such purification is impossible.
The substitutional effect of the blood substitution operation is concluded in the replacement of the patient's blood (methemoglobinemia, etc.), which has been changed morphologically and functionally, with a full blood donor, as a result of which the recipient's blood is approaching the donor blood in its composition.
The general biological effect of the operation of blood substitution is considered a general reaction of the body to bloodletting, compensated by the transfusion of donor blood, that is, essentially - a blood transplant as an individual "tissue" of the organism from several donors to the recipient. This immunobiological reaction at moderate severity has a stimulating protective effect on the body's immune system. It is expedient to isolate absolute indications for OCD operation when it is evaluated as a pathogenetic treatment and has some advantages over other methods and relative indications that can be dictated only by specific conditions when it is impossible to use other, more effective methods of artificial detoxification (HD, hemosorption, ).
Indications for the procedure
Absolute indications for blood substitution surgery - poisoning with substances that have a direct toxic effect on the blood, causing severe methemoglobinemia (more than 50-60% of the total hemoglobin), increasing massive hemolysis (at a free hemoglobin concentration of more than 10 g / l) and a decrease in cholinesterase activity of the blood up to 10%. A significant advantage of the blood substitution operation is the comparative simplicity of this method, which does not require special equipment, and the possibility of its application in the conditions of any hospital. At present, taking into account the difficulty of obtaining donor blood, OC is practically used only in young children.
[Complications after the procedure
Complications of the blood substitution surgery - temporary hypotension, posttransfusion reactions and moderate anemia in the postoperative period Complications in the process of OCD in many ways determines the clinical state of patients by the time of surgery. Most patients who had no expressed hemodynamic disorders prior to surgery tolerate it satisfactorily. With a technically correct operation, the blood pressure level is stable or changes in insignificant limits. Technical errors in the operation (disproportions in the volume of injected and withdrawn blood) lead to temporary fluctuations in BP within 15-20 mm. Gt; Art. And are easily corrected when restoring the disturbed equilibrium.
The most serious complications of blood substitution surgery include the homologous blood syndrome, which develops when large volumes of donor blood are transfused (over 3 liters) and proceeds as an immunological rejection reaction.