What is Hypervolemia?
Hypervolemia is a condition characterized by an increase in total blood volume and usually a change in Ht. There are normocythemic, oligocytemic and polycythemic hypervolemia.
Causes of Hypervolemia
Normocythemic hypervolemia (simple) – a condition manifested by an equivalent increase in the volume of the formed elements and the liquid part of the BCC. Ht remains within the normal range.
The main causes of simple hypervolemia: a large volume of blood transfusion, acute hypoxic conditions, accompanied by the release of blood from its depot, as well as significant exercise, leading to hypoxia.
Oligocytemic hypervolemia (hydremia, hemodilution) is a condition characterized by an increase in total blood volume due to an increase in its liquid portion. The indicator Ht is below the norm.
The main causes of oligocytemic hypervolemia:
- Excessive intake of fluid in patients with pathological thirst (for example, in patients with diabetes) and the introduction into the bloodstream of a large number of plasma substitutes or blood plasma.
- Reduced elimination of fluids from the body as a result of insufficiency of the excretory function of the kidneys (for example, in case of renal failure), hyperproduction of ADH, hyperosmolarity of blood plasma.
Polycythemic hypervolemia is a condition manifested by an increase in the total blood volume due to a predominant increase in the number of its formed elements. In this regard, Ht exceeds the upper limit of normal.
The main causes of polycythemic hypervolemia:
- Polycythemia (erythrocytosis) – a group of pathological conditions, characterized by an increase in the number of red blood cells (regardless of the number of leukocytes, platelets).
- True polycythemia (polycythemia vera, Vaquez disease) is a chronic leukemia with a lesion at the level of the progenitor cell myelopoiesis with a characteristic for the tumor unlimited proliferation of this cell, which retains the ability to differentiate by four sprouts, mainly by red. Erythremia is accompanied by significant erythrocytosis and, as a result, increased Ht.
- Chronic hypoxia of any type (hemic, respiratory, circulatory, tissue, etc.).
Polycythemia at the same time reflects the hyperregenerative state of the bone marrow, which is accompanied by increased proliferation of blood cells, mainly red blood cells, and their release into the vascular bed. Polycythemic hypervolemia is detected in chronic circulatory failure, alveolar hypoventilation, a decrease in the oxygen capacity of the blood and the effectiveness of biological oxidation, in exogenous (norm and hypobaric) hypoxia.
Symptoms of Hypervolemia
Hypervolemia is characterized by an increase in cardiac output and an increase in blood pressure:
- An increase in cardiac output is the result of a compensatory hyperfunction of the heart due to an increase in blood volume. However, with decompensation of the heart and the development of its insufficiency, cardiac output, as a rule, decreases.
- Increased blood pressure is mainly due to an increase in cardiac output, as well as bcc and vascular tone.
- True polycythemia is also characterized by a significant increase in blood viscosity, aggregation and agglutination of blood cells, disseminated thrombus formation, and microcirculation disorders.
Treatment of Hypervolemia