Hypovolemia: symptoms and treatment
Hypovolemia is a condition characterized by a decrease in blood volume in the human body. Hypovolemia can develop against the background of various disorders and health problems, but all of them are accompanied by the loss of fluid, or its release from the bloodstream into the surrounding tissues.
Normally, a healthy man in the body should circulate 70 ml of blood for each kilogram of weight. For women, this figure is 66 ml. Only when the vessels are filled with blood as expected, the body maintains a normal level of blood pressure. If the volumes of this life-supporting fluid decrease, then the pressure begins to fall, the person develops hypotension, the tissues suffer from oxygen starvation, the work of all internal organs is disrupted.
In the human body, water is present almost everywhere, not only in the vascular bed. It is called extracellular fluid. It is necessary to ensure tissue nutrition and to normalize metabolic processes in it. Blood and extracellular fluid are interconnected, therefore, the loss of water by the body will certainly affect the volume and concentration of blood.
The liquid part of the blood is called plasma, the rest of its volume is represented by platelets, erythrocytes and leukocytes. Depending on the type of hypovolemia, the ratio of the cellular and plasma components of the blood will differ. As a result, the total volume of circulating blood in the body decreases, and the proportions between its main constituent elements (plasma and blood cells) can also be disturbed.
Of course, all doctors are familiar with the concept of hypovolemia. However, to date, there is no clear scheme for detecting this disorder, which significantly complicates the diagnostic process. The same feature applies to the treatment of hypovolemia. Therefore, often the patient is prescribed an unjustified blood transfusion, which can harm human health. The doctor, before prescribing treatment, must identify the cause that led to hypovolemia and clearly distinguish between this concept and dehydration.
It should be borne in mind that severe hypovolemia can lead to the development of shock conditions that threaten human life. Therefore, sometimes the decision on the method of providing first aid to the patient must be made very quickly. Otherwise, it will not be possible to save his life.
- Etiology and pathogenesis of hypovolemia
- Types and clinical picture of hypovolemia
- Hypovolemia treatment
Etiology and pathogenesis of hypovolemia
What can happen in the body with hypovolemia:
- The level of proteins and electrolytes in the blood fluid and in the extracellular space changes.
- Peripheral vessels expand, thereby increasing the capacity of the vascular bed as a whole.
- Hypovolemia can develop due to the direct excretion of blood cells and plasma from the body.
The causes of hypovolemia can be as follows:
- Bleeding accompanied by blood loss.
- The development of burn disease.
- Allergic reaction.
- The development of dehydration against the background of the defeat of the body by an intestinal infection.
- Pathological or physiological hemolysis.
- Vomiting during pregnancy, provoked by toxicosis.
- Excessive flow of urine in kidney disease.
- Diabetes mellitus and insipidus.
- Not being able to consume water, such as tetanus or rabies.
- Overdose of certain medications. In terms of the development of hypovolemia, special caution should be exercised in relation to diuretics.
When the volume of blood in the body decreases, it leads to various disorders in the body. First, he tries to compensate for them on his own, and then these violations lead to irreversible consequences. It will not be possible to correct them even through therapeutic measures. Therefore, hypovolemia should be eliminated immediately after its detection.
The capacity of the vascular bed and the volume of blood are two concepts that exist in the human body in a dense ligament. With changes in the volume of fluid, the vascular bed changes its capacity to compensate for its lack or excess. If the volume of blood in the body decreases, then it reacts to this with a spasm of capillaries, which makes it possible to replenish its reserves in large vessels. Thus, he compensates (completely or partially) the onset of hypovolemia.
In case of allergies and poisoning, when the blood volume does not change, an increase in the vascular bed occurs, thus the body also tries to compensate for the relative hypovolemia. Indeed, against the background of these reactions, the return of venous blood to the heart decreases. This threatens with disruption of his work and oxygen starvation of tissues.
Hypovolemia can develop with pathologies of the endocrine and urinary system. Blood volumes decrease due to the abundant excretion of water from the body, and together with it salts are released that are able to retain fluid. Diabetes mellitus contributes to the development of hypovolemia due to the fact that glucose is present in urine, which attracts large volumes of fluid to itself.
Disruptions in the work of the pituitary gland can lead to the development of hypovolemia, since a deficiency of antidiuretic hormone provokes frequent and profuse urination. In this case, hypovolemia will not have a severe course, since the body loses with such a violation not blood supplies, but extracellular fluid.
Burn disease contributes to the development of hypovolemia due to the fact that with such tissue lesions, impressive losses of plasma occur. The situation is aggravated by the intoxication of the body. In addition, with serious burns, blood microcirculation is completely disrupted in the area that was damaged.
Intestinal infections contribute to the development of hypovolemia, since fluid will be rapidly excreted from the body against the background of severe diarrhea. Vomiting aggravates the situation. About 7 liters of fluid are formed in the intestines of a healthy adult per day, and a certain part of it also comes with food, but no more than 2% of these volumes are excreted with feces. Diarrhea can lead to dehydration very quickly.
Diarrhea and vomiting are very dangerous against the background of intestinal infection in children. The younger the child, the more rapidly dehydration develops and the more difficult it is to restore fluid reserves. Already after 2 days from the onset of the disease, the child's condition can become very serious. The situation is especially dangerous if the intestinal infection is accompanied by a high body temperature.
Although a person does not notice this, he loses fluid during breathing and also when he sweats. When an individual is healthy, the body completely controls these processes. The volume of water that a person drinks throughout the day is sufficient for him to make up for these losses (if he drinks in accordance with his age norm). When you are in the heat, with fever, with excessive physical exertion, the balance of water in the body can change.
Blood loss is the most common cause of hypovolemia. Bleeding can be external or internal. First of all, blood loss affects the functioning of the heart.
This affects the body as follows:
- Blood pressure decreases, which leads to the supply of blood from the reserve stores - from the muscles and liver.
- Urination is delayed in order to preserve body fluids.
- The blood coagulation system is activated.
- Small blood vessels spasm.
The body uses all these mechanisms to compensate for hypovolemia: it uses a blood depot, tries to preserve it in large vessels due to capillary spasm, and activates the blood coagulation system to stop bleeding. This allows for as long as possible to continue to supply blood to the life-supporting organs: the brain, heart and kidneys.
At the same time, the inclusion of such compensation mechanisms negatively affects the blood supply to peripheral organs. After all, they begin to suffer from hypoxia and acidification of the internal environment. Small vessels are more likely to form blood clots.
Provided that no emergency assistance is provided to a person, he will die from hypovolemic shock.
So, the mechanisms for the development of hypovolemic shock are identical, regardless of the cause that provoked it. At first, the body tries to compensate for the existing disorder by concentrating blood volumes in the life-supporting organs, but over time, the blood flow is decentralized, which leads to a disruption in the work of all organs. The state of shock, if it occurs, progresses very quickly.
Hypovolemic shock is the terminal stage of hypovolemia. Very often, shock leads to irreversible consequences, it is difficult to correct, it causes serious changes in the vessels and internal organs. Blood pressure is greatly reduced, all tissues experience acute hypoxia. A person develops hepatic, renal, cardiac and respiratory failure. The patient falls into a coma, which is fatal.
The picture below shows a graph of the development of hypovolemia with blood loss:
Types and clinical picture of hypovolemia
Hypovolemia is divided into 3 main types:
Normocythemic. In this case, the volumes of circulating blood and plasma decrease, and these substances fall evenly relative to each other. Bleeding, shock, and vasodilation can cause this type of hypovolemia.
Polycythemic. In this case, there is a loss of plasma, and blood cells remain unchanged. This type of hypovolemia is observed against the background of dehydration of the body, for example, with burns, diarrhea, vomiting, etc.
Oligocythemic. This type of hypovolemia is characterized by a decrease in the level of cellular elements of the blood, which is observed against the background of aplastic anemia or with hemolysis.
Sometimes the same violation can cause various types of hypovolemia, so when a person gets burns, a person may develop polycythemic hypovolemia against the background of sweating plasma or oligocythemic hypovolemia against the background of severe hemolysis.
Symptoms that occur with hypovolemia are associated with a drop in blood pressure and developing tissue hypoxia. This leads to the fact that the internal organs are not able to function normally. The more severe the hypovolemia, the more intense the symptoms of the disorder. These include:
- Great weakness.
- Abdominal pain.
The skin of the face becomes pale or even cyanotic, the pulse and respiration rate increase. Depending on the severity of the patient's condition, the work of the brain will be disrupted to one degree or another.
The skin loses the ability to normal thermoregulation, it becomes cool to the touch, the person himself gets cold, but the thermometer can show high values. As the pressure drops lower and lower, the person becomes more dizzy and may faint. In the future, without adequate assistance, shock and coma develop, and then the death of the body occurs.
In a child, hypovolemia can progress much faster than in an adult. This is especially true for children under 3 years of age. If a child develops severe diarrhea and vomiting, then he will quickly become lethargic, the skin will turn pale, the nasolabial triangle will turn blue. The fingers and the tip of the nose will become cyanotic.
Depending on the stage of development of the disease, the following symptoms of hypovolemia are distinguished:
- With mild bleeding, hypovolemia will be mild. The pressure drops by no more than 10% of the usual values. The heartbeat increases slightly, the skin turns pale, dizziness occurs, the person is thirsty. He may feel sick, the patient's condition is characterized as light-headed.
- With hypovolemia of moderate severity, blood loss will be equal to 40%. In this case, the systolic pressure drops to 90 mm. rt. Art. The patient has severe shortness of breath, sticky sweat appears, he often yawns, since the tissues suffer from hypoxia. Consciousness is clouded. The person is thirsty.
- In severe hypovolemia, massive blood loss is observed - up to 70% of its total volume. The pressure drops to 60 mm. rt. Art., the pulse is frequent, but weak, the heartbeat is very strong, the skin is pale. At this time, many patients develop convulsions, confusion, and a coma is possible.
After the onset of a severe stage of hypovolemia, shock can occur at any time. Low blood pressure causes loss of consciousness, or, on the contrary, psychomotor agitation. No urination, noisy breathing.
With the polycythemic type of hypovolemia, blood clots form in the vessels, and the tissues of the internal organs undergo necrosis against the background of a violation of their blood supply.
A person with signs of hypovolemia should be taken to the hospital. Depending on the severity of his condition and the cause that led to such disorders, such specialists as resuscitators, surgeons, infectious disease specialists will deal with therapy.
Hypovolemic shock requires urgent measures already on the part of emergency doctors.
The algorithm for their rendering:
- Stopping bleeding, if any.
- Placement of a catheter into a peripheral vein.
- The introduction of intravenous solutions to normalize the volume of circulating blood.
- Providing normal breathing to the victim, supplying oxygen.
- Administration of pain relievers - Tramadol or Fentanyl.
- The introduction of glucocorticosteroids - Dexamethasone, Prednisolone.
Provided that the measures described allowed the pressure to be normalized and it rose to a mark of 90 mm. rt. Art., the patient is urgently taken to the hospital. At the same time, infusion therapy is continued. If it is not possible to bring the pressure back to normal, then Phenylephrine, Dopamine, Norepinephrine are added to the intravenous solution.
First of all, the patient needs to restore the volume of circulating blood, which is possible by conducting infusion therapy. This allows you to prevent the progression of hypovolemia and prevent shock from developing.
Medicines used to eliminate hypovolemia:
- For infusion therapy: saline solutions such as saline, frozen plasma, rheopolyglucin, or albumin.
- To restore the quality composition of blood, platelet or erythrocyte mass can be transfused.
- Insulin or glucose in solution is administered intravenously.
- Corticosteroid hormones are administered intravenously.
- Aminocaproic acid or etamsylate can be used to stop bleeding.
- Seduxen is indicated to relieve seizures.
- To prevent hypovolemic shock, Kontrikal is used.
- If necessary, antibacterial drugs are prescribed.
It is imperative to monitor blood pressure, to ensure that it does not drop less than 70 mm. rt. Art. At the same time, the patient is injected with crystalloid saline solutions. As much liquid should be injected as the person has lost blood.
If with the help of solutions it is not possible to restore blood pressure, then infusion therapy is supplemented with dextrans, drugs with starch and gelatin, plasma, vasotonics (Dopamine, Adrenaline, etc.).
In parallel, the person is allowed to breathe oxygen, or they connect him to a ventilator. Albumin and Heparin are administered in order to prevent blood clotting, that is, to resist the process of blood clots formation.
It is possible that it will be necessary to eliminate the bleeding by surgery, and interventions are also carried out for intestinal obstruction, peritonitis, pneumothorax and other conditions requiring the help of a surgeon.
To eliminate hypovolemia, the patient is placed in the intensive care unit, which allows for round-the-clock monitoring of the person's condition. They control the electrolyte balance of blood, hemostasis, blood pressure, the amount of oxygen in the blood, and kidney function. Depending on the data obtained, the treatment is selected and adjusted. Without fail, efforts are directed at eliminating the cause that caused hypovolemia.
The author of the article: Shutov Maxim Evgenievich | Hematologist
Education: In 2013 he graduated from the Kursk State Medical University and received a diploma "General Medicine". After 2 years, completed residency in the specialty "Oncology". In 2016 completed postgraduate studies at the National Medical and Surgical Center named after N. I. Pirogov.