Hemodilution is one of the methods of blood treatment. It allows you to limit the number of allogeneic (donated) blood transfusions, which is of great importance if you do not consent to such a procedure. However, haemodilution has some dangers. It is worth finding out what exactly is, what are the advantages and dangers of this treatment.

Contents:

  1. Hemodilution: what is it?
  2. Hemodilution: when is it used?
  3. Hemodilution: limitations
  4. Hemodilution: Benefits
  5. Hemodilution: threats

Hemodilution is a procedure in which the patient is transfused with his own blood during the procedure. The operation is performed on "diluted" blood, and in the event of loss of blood, the supplies collected before the procedure are given. This procedure has many advantages - it allows you to avoid post-transfusion reactions, but on the other hand, it requires planning blood transfusion, reduces the patient's comfort and exposes him to other complications, e.g. electrolyte disturbances.

Hemodilution: what is it?

Hemodilution is performed just before the planned procedure, usually in the operating room. They are used if there is a high risk of blood loss during surgery. Hemodilution takes a certain amount of blood from the patient, usually several hundred milliliters, which is replenished with intravenous fluids so that blood pressure does not drop. This causes a dilution of the blood, a decrease in hematocrit and hemoglobin, in such conditions the operation is performed. If there is a lot of blood loss during the procedure, the collected amount is used during or immediately after the surgery - it is fed back into the blood vessels. Excess fluid can be removed by administering diuretics.

Hemodilution: when is it used?

Hemodilution is performed before major surgical procedures associated with a significant risk of bleeding complications, such as cardiac thoracic surgery. The use of haemodilution is particularly useful in patients for whom transfusion of blood from donors may be risky, e.g. in the presence of many unusual antibodies in the blood, which may cause difficulties in selecting appropriate blood products for the transfusion. This treatment isalso one of the treatment methods for people who refuse to receive blood transfusions, e.g. Jehovah's Witnesses.

Hemodilution: limitations

Taking blood with the next replacement of its volume with fluid is burdensome for the body, therefore seriously ill people cannot undergo this procedure. Hemodilution is not used in the surgical treatment of injuries, as they are associated with a large loss of blood before the procedure. In addition, the contraindications are:

  • anemia, known anemia, should not be made worse, and if the hemoglobin value is very low, surgery should not be performed
  • chronic obstructive pulmonary disease
  • kidney failure
  • cirrhosis of the liver
  • severe blood coagulation disorders
  • viral infection - hepatitis B and hepatitis C, HIV, bacterial infections, because giving blood with pathogens will be an additional burden for the patient
  • advanced, unstable ischemic heart disease, as reducing the amount of hemoglobin will reduce the amount of oxygen supplied to the heart
  • severe aortic stenosis
  • uncontrolled hypertension
  • cerebral circulation disorders, because, as in the case of the heart, it may lead to hypoxia

Hemodilution: Benefits

The main advantage of hemodilution is to avoid transfusing foreign blood, and thus immunizing the patient - it does not produce antibodies against antigens present in blood collected from donors. After a blood transfusion, everyone will develop a small amount of antibodies against antigens in foreign blood, this is normal and common.

This may result in reacting with antigens contained in the next transfused unit of blood, and this phenomenon is already very unfavorable. The possibility of its occurrence is tested before each blood administration by making a so-called cross-test. If a reaction of the prepared blood with the recipient's antibodies is detected, do not give this unit and look for another unit that will not cause this reaction.

For people who have had multiple blood transfusions and have developed many types of antibodies, this can make it difficult to find the right blood for a transfusion. Moreover, haemodilution helps to avoid rare but occurring post-transfusion complications: haemolysis, allergic reactions or haemolytic reactions.

Moreover, diluting blood is believed to improve blood flow to the heart and brain among others as wellreduces the viscosity, which in turn reduces the load on the heart. Interestingly, despite the significant dilution of blood - a decrease in the concentration of platelets and substances responsible for clotting, it has not been proven that hemodilution increases the risk of bleeding.

Is blood transfusion safe?

Blood transfusion: when is it needed?

What is serum and when do we administer it?

Hemodilution: threats

Unfortunately, despite numerous advantages, hemodilution should not always be used, and its performance is associated with certain risks. First of all, there is a group of contraindications - the one mentioned above, which limits the possibility of performing this procedure in a fairly large group of patients.

These contraindications do not apply to "standard" blood donation transfusions, which makes it much more accessible. Moreover, administration of large amounts of fluids during haemodilution carries a certain risk of complications: hyperhydration, electrolyte disturbances: hyponatremia, hypokalemia, worsening of heart failure.

Blood drawn during hemodilution must be used fairly quickly as it is not permanently preserved, which is important in the postoperative course. One of the risks following surgery is bleeding at the site of surgery, usually within a few days. If it leads to a blood transfusion, it is not possible to give the blood that has been previously collected.

However, the greatest disadvantage of hemodilution is the need to plan it, and the need for blood transfusion in a huge percentage of cases is not possible to predict - we do not know when an accident, emergency surgery, gastrointestinal bleeding or many other situations leading to serious blood loss. That is why it is so important to donate blood, which will enable continuous access to blood products at blood donation stations.

Autotransfusion

A method similar to hemodilution is autotransfusion, but with different time frames. To carry out it, it is necessary to prepare the patient and collect blood a few or several days earlier. So blood is obtained before surgery so that the body can rebuild the blood cells. After collection, the bone marrow is mobilized very quickly to produce new blood cells and the liver to produce plasma proteins, which usually takes about a week. After such a procedure, the drawn blood is preserved and can be used if transfusion is necessary.

About the authorBow. Maciej GrymuzaA graduate of the Faculty of Medicine at the Medical University of K. Marcinkowski in Poznań. He graduated fromover good result. Currently, he is a doctor in the field of cardiology and a doctoral student. He is particularly interested in invasive cardiology and implantable devices (stimulators).

Category:

Cardiology