Hemorrhagic shock is a complex of hemodynamic and metabolic disorders that occur due to acute blood loss. The cause of the emergency condition is injuries, internal bleeding with damage to the integrity of organs and vascular walls. Pathology is manifested by pallor of the skin and cold sweat, cardiac disorders, progressive depression of consciousness up to coma. Diagnosis is carried out according to clinical and laboratory signs and is combined with emergency therapy, which includes the introduction of blood substitutes, correction of metabolic acidosis, elimination of peripheral vascular spasm.
R57.1 Hypovolemic shock
Hemorrhagic shock belongs to the group of hypovolemic shocks and is an urgent condition requiring treatment of the patient in the intensive care unit. It is not an independent nosology and is a nonspecific pathological syndrome that occurs against the background of other health disorders. Hemorrhagic shock is of particular importance for specialists in all fields of medicine, since it is characterized by rapid progression, severe course and unfavorable prognosis in the absence of emergency care.
The main etiological factor of shock is trauma: fractures of large bones, multiple fractures of bones with multiplication of soft tissues, wounds of internal organs. Less often, the cause is blunt abdominal injuries, which are accompanied by rupture of the spleen of the liver or other organs. Injuries most often occur in everyday life, less often – in an accident, at work as a result of criminal or military actions. In addition to injury, the causes of hemorrhagic shock can be:
- Gastrointestinal diseases. Massive bleeding is observed as a complication of gastric ulcer and duodenal ulcer, reflux esophagitis, Mallory-Weiss syndrome. Blood loss is possible with cirrhosis of the liver, which is complicated by portal hypertension and varicose veins of the esophagus. Less often, pathology occurs when malignant tumors of the stomach and intestines disintegrate.
- Respiratory diseases. The leading causes of pulmonary hemorrhage are tumors of the bronchi and lungs in the advanced stage, untreated pulmonary tuberculosis. Less often, pathology develops with a complicated course of pneumonia, lung infarction, gangrene and other purulent-destructive processes in the lung tissue.
- Gynecological diseases. In pregnant women, pathology can occur with placenta previa, premature detachment of the normally located placenta, spontaneous termination of pregnancy. In the labor and postpartum period, bleeding occurs with atony or rupture of the uterus. In non-pregnant patients, massive metrorrhagia is observed with submucous fibroids.
The main predisposing factor of hemorrhagic shock are disorders of the hemostatic system, which are associated with thrombocytopenia, thrombocytopathies, coagulopathies. Conditions occur with aplastic anemia, thrombocytopenic purpura, hereditary pathologies (hemophilia, Willebrand’s disease). The probability of profuse bleeding increases in people who take anticoagulants and antiplatelet agents for a long time without monitoring the parameters of the blood coagulation system.
Normally, compensatory mechanisms ensure the adaptation of hemodynamics and prevent the development of shock. If the deficit of circulating blood volume (CBV) exceeds 20%, which corresponds to 1 liter, decompensation develops and homeostasis is disrupted. The pathological process starts with a narrowing of peripheral vessels and a decrease in blood flow in them. This is accompanied by the redistribution of fluid, the transfer of water from the cells and interstitial space into the vessels.
If the CBV is not replenished, blood loss leads to pronounced spasm of peripheral vessels, critical deterioration of microcirculation and changes in the rheological properties of blood. Hypoxia increases in the tissues, accompanied by an expansion of the vascular space and an increase in the discrepancy between the volume of blood and the vascular bed. Under-oxidized foods accumulate in the body, energy processes are disrupted, and central blood circulation worsens.
In the late stages of hemorrhagic shock, the mechanisms of disseminated intravascular coagulation are activated. DIC syndrome is caused by progressive acidosis, which enhances the work of the internal hemostasis system and promotes the formation of blood clots. In severe cases, the shock ends with irreversible activation of the fibrinolytic system, which corresponds to a critical condition and an unfavorable prognosis for the patient.
According to clinical signs, hemorrhagic shock is divided into reversible, which can be compensated and decompensated, and irreversible, diagnosed with massive blood loss and prolonged hypotension. According to the magnitude of the losses of the CBV, a state of mild, moderate and severe severity is distinguished. In emergency medicine, there is a widespread classification according to clinical and laboratory indicators, which includes 4 degrees:
- 1 degree. It is diagnosed with a deficiency of 15-20% CBV and is characterized by a satisfactory condition of the patient. It is characterized by a systolic blood pressure index (SBPI) of about 100 mm Hg, a pulse of 80-100 beats. The level of hemoglobin in the blood is more than 90 g / l, which corresponds to a mild degree of anemia.
- 2nd degree. It is determined with losses of CBV from 20% to 30% and is characterized by a progressive deterioration in the well-being of the victim. The SBPI indicator decreases to 80-90 mm Hg, the heart rate increases to 100-120 beats, the hemoglobin level corresponds to moderate or severe anemia.
- 3rd degree. It is established with blood loss in the range of 30-40% of the CBV and is manifested by a severe general condition of the patient. SBPI is no more than 60-70 mm Hg, the heart rate increases to 140 beats, the body temperature drops sharply.
- 4th degree. It is observed with a critical decrease in CBV – more than 40% of the initial values. With this degree of hemorrhagic shock, the measurement of arterial and central venous pressure is difficult. The patient is in a comatose state.
At the initial stage, drowsiness, weakness, dizziness and darkening of the eyes occur. The patient has pale and cool skin, rapid shallow breathing, rapid and weakened pulse. It is characterized by a decrease in the volume of urination by 2 times. At this stage, the consciousness of patients is preserved, they are adequately oriented in time and space, answer questions meaningfully, but thinking and the pace of speech are slowed down.
The progression of the disease is manifested by disorders of consciousness in the form of lethargy, pathological drowsiness, delayed reaction to external stimuli. The skin becomes sharply pale, characterized by a bluish hue of the distal extremities (acrocyanosis). Patients are covered with copious cold sweat, have rapid and irregular breathing. The pulse becomes weak and frequent — up to 130 beats per minute, blood pressure decreases.
The decompensated course of hemorrhagic shock is characterized by loss of consciousness, marbled skin pattern, lack of urination. The patient’s breathing becomes weak and arrhythmic. It is not possible to determine the pulse in the peripheral vessels, the heart rate exceeds 140 beats. Systolic pressure is about 60 mmHg, while diastolic blood pressure is often impossible to determine.
In the absence of timely correction of blood loss, hemorrhagic shock causes total disorders of macrocirculation and microcirculation, which culminate in disorders of all types of metabolism. There is a high probability of death, which is caused by deep hypoxia of the brain and other vital organs, cardiac arrest against the background of severe hypovolemia, multiple organ failure.
Since patients with hemorrhagic shock require emergency therapy, the examination is performed in the intensive care unit at the same time as the start of treatment. In the presence of signs of blood loss and clinical symptoms of shock, the preliminary diagnosis is not difficult. An extended examination is prescribed to assess the general condition of the patient, to determine possible causes of pathology. The diagnostic complex includes the following methods:
- Determination of the Algover shock index. The indicator is used to quickly assess the severity of bleeding. It is equal to the ratio of the heart rate in one minute to the systolic pressure indicator. The normal value of the shock index is about 0.5, an increase in the indicator is observed in hemodynamic disorders.
- Blood test. It is possible to determine the presence and severity of CBV loss by the level of hematocrit, erythrocytes and hemoglobin. To assess the degree of blood clotting disorder, a coagulogram is performed. The data of biochemical blood analysis provide valuable information about the work of the liver and kidneys, the possible root cause of bleeding.
- Instrumental methods. In the absence of a visible source of blood loss and suspected hemorrhagic shock, abdominal ultrasound, chest X-ray and other imaging methods of internal bleeding are performed. In emergency situations, laparoscopy and / or thoracoscopy is performed for therapeutic and diagnostic purposes.
Pathology must be distinguished from other types of critical hypovolemia: traumatic, toxic-infectious, anaphylactic shock. An important role in the diagnosis is played by clarifying the conditions under which the deterioration of well-being occurred, the identification of concomitant symptoms. If there are no obvious signs of blood loss, differential diagnosis is carried out with acute heart failure and other causes of cardiogenic shock.
When eliminating hemodynamic disorders, replenishing the amount of circulating blood becomes of paramount importance. For this purpose, infusion solutions are introduced — crystalloid and colloidal preparations in a ratio of 2: 1. To normalize the blood composition, freshly frozen plasma, erythrocyte and platelet mass are used. The volume of transfusion solutions is calculated taking into account the loss of CBV and laboratory parameters.
In addition to blood substitutes, sodium bicarbonate solutions are used to eliminate metabolic acidosis, a key pathogenetic factor in the progression of hypoxia and ischemia. To normalize vital functions, inhalations of moistened oxygen, the introduction of osmotic or loop diuretics with inadequate diuresis, the use of cardiac glycosides in cardiac disorders are indicated.
An important problem of hemorrhagic shock is peripheral vasoconstriction, associated with inadequate blood supply to tissues and aggravation of metabolic disorders. For its correction, warming of the patient is shown, which simultaneously eliminates hypothermia and eliminates vascular spasm. Vasopressor drugs are not prescribed, despite the severity of hypotension, because they aggravate vascular spasm and aggravate the patient’s condition.
Prognosis and prevention
The outcome depends on the amount of blood loss and the timeliness of care. With the loss of up to 30% of the CBV and the beginning of treatment in the first 2-3 hours from the action of the causal factor, the survival rate is about 80%. With massive blood loss and the start of treatment after more than 4 hours, the prognosis is unfavorable due to irreversible changes in body tissues. Prevention is aimed at reducing injuries and comprehensive treatment of somatic diseases that are complicated by bleeding.