What is Hypovolemia?
Hypovolemia – a condition characterized by a decrease in the total volume of blood and, as a rule, a violation of the ratio of its uniform elements and plasma. There are normocytemic, oligocytemic and polycythemic hypovolemia.
Causes of Hypovolemia
Normocytemic hypovolemia is a condition manifested by a decrease in the total blood volume while maintaining Ht within normal limits.
- The most common causes of normocytemic hypovolemia: acute blood loss, shock conditions, vasodilation collapse. In the last two cases, normocytemic hypovolemia develops as a result of the deposition of a large volume of blood in venous (capacitive) vessels and a significant decrease in this regard of BCC.
- Manifestations of normocytemic hypovolemia are determined by the nature of the cause that caused it (blood loss, shock, collapse), as well as the inclusion of compensation mechanisms aimed at eliminating acute hypoxia.
Oligocytemic hypovolemia is a condition characterized by a decrease in the total volume of blood with a predominant decrease in the number of its shaped elements. Ht is below normal.
The most common causes of oligocytemic hypovolemia.
- Conditions after acute hemorrhage (at the stage when the transport of fluid from the tissues and the release of deposited blood into the vascular bed do not yet eliminate hypovolemia, and the flow of blood cells from the hematopoietic organs causes red blood cell deficiency).
- Erythropenia as a result of massive hemolysis of erythrocytes (for example, with burns of a large surface of the body, when hemolysis is combined with the loss of the body’s liquid part of the blood due to plasmorrhagia) and suppression of erythropoiesis (for example, in aplastic or regenerative conditions).
Polycythemic hypovolemia is a condition in which a decrease in the total volume of blood in the body is caused mainly by a decrease in plasma volume. Ht in this condition is above the normal range.
The most common causes of polycythemic hypovolemia.
- Conditions that cause increased loss of body fluid: repeated vomiting (for example, in pregnant women or as a result of exogenous intoxication), prolonged diarrhea (for example, with impaired membrane digestion, intestinal toxic infections), polyuria (for example, with renal failure), increased and prolonged sweating ( for example, in hot climates or in hot workshops at the factory) and extensive skin burns (accompanied by plasmorrhagia).
- Conditions that impede the sufficient flow of fluid into the body (water starvation): lack of drinking water and the inability to drink water (for example, as a result of muscle spasm during tetanus or rabies).
Symptoms of Hypovolemia
Manifestations of oligocytemic hypovolemia.
- A decrease in the oxygen capacity of the blood (as a result of erythropenia).
- Signs of hypoxia (for example, a decrease in the oxygen content in the blood, acidosis, a decrease in p02 of venous blood, etc.).
- Disorders of organ tissue circulation and microcirculation of varying degrees, due, among other factors, to a decrease in bcc.
Manifestations of polycythemic hypovolemia.
- Violations of organ tissue microcirculation in connection with hypovolemia and polycythemia.
- Increased blood viscosity, aggregation of blood cells in the microvasculature of organs and tissues and disseminated microthrombosis.
- Signs of the underlying pathology causing polycythemic hypovolemia (e.g., shock, diabetes insipidus, renal failure, burn disease, etc.).