Shock most often develops due to... Shock - types of shock, symptoms, first aid

Story

The state of shock was first described by Hippocrates. The term “shock” was first used in Le Dran. At the end of the 19th century, possible mechanisms for the development of the pathogenesis of shock began to be proposed, among them the following concepts became the most popular:

• paralysis of the nerves innervating the vessels;
• depletion of the vasomotor center;
• neurokinetic disorders;
• dysfunction of the endocrine glands;
• decrease in circulating blood volume (CBV);
• capillary stasis with impaired vascular permeability.

Pathogenesis of shock

From a modern point of view, shock develops in accordance with G. Selye's theory of stress. According to this theory, excessive exposure to the body causes specific and nonspecific reactions in it. The first ones depend on the nature of the effect on the body. The second - only from the force of influence. Nonspecific reactions when exposed to a super-strong stimulus are called general adaptation syndrome. General adaptation syndrome always occurs in the same way, in three stages:

1. stage compensated (reversible)
2. decompensated stage (partially reversible, characterized by a general decrease in the body’s resistance and even death of the body)
3. terminal stage (irreversible, when no therapeutic interventions can prevent death)

Thus, shock, according to Selye, is a manifestation nonspecific reaction body to excessive influence.

Hypovolemic shock

This type of shock occurs as a result of a rapid decrease in circulating blood volume, which leads to a drop in the filling pressure of the circulatory system and a decrease in venous return of blood to the heart. As a result, a disturbance in the blood supply to organs and tissues and their ischemia develops.

Reasons

Circulating blood volume can quickly decrease due to the following reasons:

• blood loss;
• plasma loss (for example, due to burns, peritonitis);
• loss of fluid (for example, with diarrhea, vomiting, profuse sweating, diabetes mellitus and diabetes insipidus).

Stages

Depending on the severity of hypovolemic shock, three stages are distinguished in its course, which successively replace each other. This

• The first stage is non-progressive (compensated). At this stage there are no vicious circles.
• The second stage is progressive.
• The third stage is the stage of irreversible changes. At this stage, no modern antishock drugs can bring the patient out of this state. At this stage, medical intervention can return blood pressure and cardiac output to normal for a short period of time, but this does not stop the destructive processes in the body. Among the reasons for the irreversibility of shock at this stage, a violation of homeostasis is noted, which is accompanied by severe damage to all organs, especially damage to the heart.

Vicious circles

With hypovolemic shock, many vicious circles are formed. Among them, the most important is the vicious circle that promotes myocardial damage and the vicious circle that promotes insufficiency of the vasomotor center.

Vicious circle promoting myocardial damage

A decrease in circulating blood volume leads to a decrease in cardiac output and a drop in blood pressure. A drop in blood pressure leads to a decrease in blood circulation in the coronary arteries of the heart, which leads to a decrease in myocardial contractility. A decrease in myocardial contractility leads to an even greater decrease in cardiac output, as well as a further drop in blood pressure. The vicious circle closes.

Vicious circle promoting vasomotor center insufficiency

Hypovolemia is caused by a decrease in cardiac output (that is, a decrease in the volume of blood expelled from the heart in one minute) and a decrease in blood pressure. This leads to a decrease in blood flow in the brain, as well as to disruption of the vasomotor (vasomotor) center. The latter is located in the medulla oblongata. One of the consequences of a disorder in the vasomotor center is considered to be a decrease in the tone of the sympathetic nervous system. As a result, the mechanisms of centralization of blood circulation are disrupted, blood pressure drops, and this, in turn, triggers a violation of cerebral circulation, which is accompanied by even greater depression of the vasomotor center.

Shock organs

Recently, the term “shock organ” (“shock lung” and “shock kidney”) has often been used. This means that exposure to a shock stimulus disrupts the function of these organs, and further disturbances in the condition of the patient’s body are closely related to changes in the “shock organs”.

"Shock Lung"

Story

The term was first coined by Ashbaugh to describe the syndrome of progressive acute respiratory failure. However, back in the year Burford And Burbank described a similar clinical and anatomical syndrome, calling it "wet (moist) lung". After some time, it was discovered that the picture of “shock lung” occurs not only with shock, but also with craniocerebral, thoracic, abdominal injuries, blood loss, prolonged hypotension, aspiration of acidic gastric contents, massive transfusion therapy, increasing cardiac decompensation, pulmonary embolism. Currently, no relationship has been found between the duration of shock and the severity of pulmonary pathology.

Etiology and pathogenesis

The most common cause of the development of “shock lung” is hypovolemic shock. Ischemia of many tissues, as well as a massive release of catecholamines, lead to the entry into the blood of collagen, fat and other substances that cause massive thrombus formation. Because of this, microcirculation is disrupted. A large number of blood clots settle on the surface of the pulmonary vessels, which is due to the structural features of the latter (long convoluted capillaries, double blood supply, shunting). Under the influence of inflammatory mediators (vasoactive peptides, serotonin, histamine, kinins, prostaglandins), vascular permeability in the lungs increases, bronchospasm develops, the release of mediators leads to vasoconstriction and damage.

Clinical picture

Shock lung syndrome develops gradually, usually reaching its apogee after 24-48 hours, often resulting in massive (often bilateral) damage to the lung tissue. The process is clinically divided into three stages.

1. First stage (initial). Arterial hypoxemia (lack of oxygen in the blood) predominates; the X-ray picture of the lung is usually not changed (with rare exceptions, when X-ray examination shows an increase in the pulmonary pattern). There is no cyanosis (blue discoloration of the skin). The partial pressure of oxygen is sharply reduced. Auscultation reveals scattered dry rales.
2. Second stage. In the second stage, tachycardia increases, that is, the heart rate increases, tachypnea (respiratory rate) occurs, the partial pressure of oxygen decreases even more, mental disorders intensify, and the partial pressure of carbon dioxide increases slightly. Auscultation reveals dry and sometimes fine rales. Cyanosis is not expressed. X-ray reveals a decrease in the transparency of the lung tissue, bilateral infiltrates and unclear shadows appear.
3. Third stage. In the third stage, the body is not viable without special support. Cyanosis develops. X-ray reveals an increase in the number and size of focal shadows with their transition to confluent formations and total darkening of the lungs. The partial pressure of oxygen decreases to critical levels.

"Shock Kidney"

Pathological specimen of a kidney from a patient who died of acute renal failure.

The concept of “shock kidney” reflects acute renal dysfunction. In the pathogenesis, the leading role is played by the fact that during shock, a compensatory shunting of arterial blood flow into the direct veins of the pyramids occurs with a sharp decrease in the volume of hemodynamics in the area of ​​the renal cortex. This is confirmed by the results of modern pathophysiological studies.

Pathological anatomy

The kidneys are somewhat enlarged in size, swollen, their cortical layer is anemic, pale gray in color, the peri-cerebral zone and pyramids, on the contrary, are dark red. Microscopically, in the first hours, anemia of the vessels of the cortical layer and a sharp hyperemia of the peri-cerebral zone and direct veins of the pyramids are determined. Microthrombosis of the capillaries of the glomeruli and afferent capillaries is rare.

Subsequently, increasing dystrophic changes in the nephrothelium are observed, covering first the proximal and then the distal parts of the nephron.

Clinical picture

The picture of a “shock” kidney is characterized by a clinical picture of progressive acute renal failure. In its development, acute renal failure during shock goes through four stages:

The first stage occurs while the cause that caused acute renal failure is in effect. Clinically, there is a decrease in diuresis.

Second stage (oligoanuric). The most important clinical signs of the oligoanuric stage of acute renal failure include:

• oligoanuria (with the development of edema);
• azotemia (smell of ammonia from the mouth, itching);
• an increase in the size of the kidneys, lower back pain, a positive Pasternatsky sign (the appearance of red blood cells in the urine after tapping in the area of ​​​​the projection of the kidneys);
• weakness, headache, muscle twitching;
• tachycardia, expansion of the borders of the heart, pericarditis;
• dyspnea, congestive wheezing in the lungs up to interstitial pulmonary edema;
• dry mouth, anorexia, nausea, vomiting, diarrhea, cracks in the mucous membrane of the mouth and tongue, abdominal pain, intestinal paresis;

Third stage (restoration of diuresis). Diuresis can normalize gradually or rapidly. The clinical picture of this stage is associated with the resulting dehydration and diselectrolythemia. The following symptoms develop:

• weight loss, asthenia, lethargy, lethargy, possible infection;
• normalization of nitrogen excretory function.

Stage four (recovery). Homeostasis indicators, as well as kidney function, return to normal.

Literature

• Ado A. D. Pathological physiology. - M., “Triad-X”, 2000. P. 54-60
• Klimiashvili A.D. Chadayev A.P. Bleeding. Blood transfusion. Blood substitutes. Shock and resuscitation. - M., “Russian State Medical University”, 2006. P. 38-60
• Meerson F.Z., Pshennikova M.G. Adaptation to stressful situations and physical activity. - M., “Triad-X”, 2000. P. 54-60
• Poryadin G.V. Stress and pathology. - M., “Miniprint”, 2002. P. 3-22
• Struchkov V.I. General surgery. - M., “Medicine”, 1978. P. 144-157
• Sergeev S.T.. Surgery of shock processes. - M., “Triad-X”, 2001. P. 234-338

Notes

Emergency conditions in endocrinology

Shock is a pathological change in the functions of the vital systems of the body, in which there is a violation of breathing and circulation. This condition was first described by Hippocrates, but the medical term appeared only in the mid-18th century. Since various diseases can lead to the development of shock, for a long time scientists have proposed a large number of theories of its occurrence. However, none of them explained all the mechanisms. It has now been established that the basis of shock is arterial hypotension, which occurs when the volume of circulating blood decreases, cardiac output and general peripheral vascular resistance decrease, or when fluid is redistributed in the body.

Manifestations of shock

The symptoms of shock are largely determined by the cause that led to its appearance, but there are also common features of this pathological condition:

• impaired consciousness, which can manifest itself as agitation or depression;
• decrease in blood pressure from minor to critical;
• an increase in heart rate, which is a manifestation of a compensatory reaction;
• centralization of blood circulation, in which spasm of peripheral vessels occurs, with the exception of the renal, cerebral and coronary;
• pallor, marbling and cyanosis of the skin;
• rapid shallow breathing that occurs with increasing metabolic acidosis;
• change in body temperature, usually it is low, but during an infectious process it is increased;
• the pupils are usually dilated, the reaction to light is slow;
• in particularly severe situations, generalized convulsions, involuntary urination and defecation develop.

There are also specific manifestations of shock. For example, when exposed to an allergen, bronchospasm develops and the patient begins to choke; with blood loss, a person experiences a pronounced feeling of thirst, and with myocardial infarction, chest pain.

Degrees of shock

Depending on the severity of shock, there are four degrees of its manifestations:

1. Compensated. At the same time, the patient’s condition is relatively satisfactory, the function of the systems is preserved. He is conscious, systolic blood pressure is reduced, but exceeds 90 mm Hg, pulse is about 100 per minute.
2. Subcompensated. Violation is noted. The patient's reactions are inhibited and he is lethargic. The skin is pale and moist. The heart rate reaches 140-150 per minute, breathing is shallow. The condition requires prompt medical intervention.
3. Decompensated. The level of consciousness is reduced, the patient is very inhibited and reacts poorly to external stimuli, does not answer questions or answers in one word. In addition to pallor, there is marbling of the skin due to impaired microcirculation, as well as cyanosis of the fingertips and lips. The pulse can only be determined in the central vessels (carotid, femoral artery); it exceeds 150 per minute. Systolic blood pressure is often below 60 mmHg. There is a disruption in the functioning of internal organs (kidneys, intestines).
4. Terminal (irreversible). The patient is usually unconscious, breathing is shallow, and the pulse is not palpable. By the usual method using a tonometer, pressure is often not determined, and heart sounds are muffled. But blue spots appear on the skin in places where venous blood accumulates, similar to cadaveric ones. Reflexes, including pain, are absent, the eyes are motionless, the pupil is dilated. The prognosis is extremely unfavorable.

To determine the severity of the condition, you can use the Algover shock index, which is obtained by dividing the heart rate by the systolic blood pressure. Normally it is 0.5, with the 1st degree -1, with the second -1.5.

Types of shock

Depending on the immediate cause, there are several types of shock:

1. Traumatic shock resulting from external influence. In this case, the integrity of some tissues is violated and pain occurs.
2. Hypovolemic (hemorrhagic) shock develops when the volume of circulating blood decreases due to bleeding.
3. Cardiogenic shock is a complication of various heart diseases (tamponade, aneurysm rupture), in which the ejection fraction of the left ventricle sharply decreases, resulting in arterial hypotension.
4. Infectious-toxic (septic) shock is characterized by a pronounced decrease in peripheral vascular resistance and an increase in the permeability of their walls. As a result, a redistribution of the liquid part of the blood occurs, which accumulates in the interstitial space.
5. develops as an allergic reaction in response to intravenous exposure to a substance (injection, insect bite). In this case, histamine is released into the blood and blood vessels dilate, which is accompanied by a decrease in pressure.

There are other types of shock, which include various symptoms. For example, burn shock develops as a result of injury and hypovolemia due to large losses of fluid through the wound surface.

Help with shock

Every person should be able to provide first aid for shock, since in most situations minutes count:

1. The most important thing to do is to try to eliminate the cause that caused the pathological condition. For example, if there is bleeding, you need to clamp the arteries above the injury site. And when an insect bites you, try to prevent the poison from spreading.
2. In all cases, with the exception of cardiogenic shock, it is advisable to elevate the victim's legs above his head. This will help improve blood flow to the brain.
3. In cases of extensive injuries and suspected spinal injuries, it is not recommended to move the patient until the ambulance arrives.
4. To replenish fluid losses, you can give the patient a drink, preferably warm, water, as it will be absorbed faster in the stomach.
5. If a person has severe pain, he can take an analgesic, but it is not advisable to use sedatives, since this will change the clinical picture of the disease.

In cases of shock, emergency doctors use either intravenous solutions or vasoconstrictors (dopamine, adrenaline). The choice depends on the specific situation and is determined by a combination of various factors. Medical and surgical treatment of shock directly depends on its type. Thus, in case of hemorrhagic shock, it is urgent to replenish the volume of circulating blood, and in case of anaphylactic shock, antihistamines and vasoconstrictors must be administered. The victim must be urgently taken to a specialized hospital, where treatment will be carried out under the monitoring of vital signs.

The prognosis for shock depends on its type and degree, as well as the timeliness of assistance. With mild manifestations and adequate therapy, recovery almost always occurs, while with decompensated shock there is a high probability of death, despite the efforts of doctors.

Shock is a specific condition in which there is a sharp lack of blood to the most important human organs: the heart, brain, lungs and kidneys. Thus, a situation arises in which the available volume of blood is not enough to fill the existing volume of blood vessels under pressure. To some extent, shock is a state that precedes death.

Reasons

The causes of shock are due to a violation of the circulation of a fixed volume of blood in a certain volume of vessels, which are capable of narrowing and expanding. Thus, among the most common causes of shock are a sharp decrease in blood volume (blood loss), a rapid increase in blood vessels (vessels dilate, usually in response to acute pain, allergen or hypoxia), as well as the inability of the heart to perform its functions ( heart contusion from a fall, myocardial infarction, “bending” of the heart during tension pneumothorax).

That is, shock is the body’s inability to ensure normal blood circulation.

Among the main manifestations of shock are a rapid pulse above 90 beats per minute, a weak thread-like pulse, low blood pressure (up to its complete absence), rapid breathing, in which a person at rest breathes as if he were performing heavy physical activity. Pale skin (skin becomes pale blue or pale yellow), lack of urine, and severe weakness in which a person cannot move or speak are also signs of shock. The development of shock can lead to loss of consciousness and lack of response to pain.

Types of shock

Anaphylactic shock is a form of shock characterized by a sharp dilation of blood vessels. The cause of anaphylactic shock can be a certain reaction to an allergen entering the human body. This could be a bee sting or the injection of a drug to which the person is allergic.

The development of anaphylactic shock occurs when an allergen enters the human body, regardless of the quantities in which it enters the body. For example, it does not matter at all how many bees have bitten a person, since the development of anaphylactic shock will occur in any case. However, the location of the bite is important, since if the neck, tongue or facial area is affected, the development of anaphylactic shock will occur much faster than with a bite to the leg.

Traumatic shock is a form of shock characterized by an extremely serious condition of the body, provoked by bleeding or painful irritation.

Among the most common causes of traumatic shock are pale skin, sticky sweat, indifference, lethargy, and rapid pulse. Other causes of traumatic shock include thirst, dry mouth, weakness, anxiety, unconsciousness or confusion. These signs of traumatic shock are to some extent similar to the symptoms of internal or external bleeding.

Hemorrhagic shock is a form of shock in which there is an emergency condition of the body that develops as a result of acute blood loss.

The degree of blood loss has a direct impact on the manifestation of hemorrhagic shock. In other words, the strength of the manifestation of hemorrhagic shock directly depends on the amount by which the circulating blood volume (CBC) decreases in a fairly short period of time. A blood loss of 0.5 liters, which occurs over the course of a week, will not provoke the development of hemorrhagic shock. In this case, the clinic of anemia develops.

Hemorrhagic shock occurs as a result of blood loss in a total volume of 500 ml or more, which is 10-15% of the circulating blood volume. A loss of 3.5 liters of blood (70% of the blood volume) is considered fatal.

Cardiogenic shock is a form of shock characterized by a complex of pathological conditions in the body, provoked by a decrease in the contractile function of the heart.

Among the main signs of cardiogenic shock are interruptions in the functioning of the heart, which are a consequence of cardiac arrhythmias. In addition, with cardiogenic shock, there are interruptions in the functioning of the heart, as well as pain in the chest. Myocardial infarction is characterized by a strong feeling of fear with pulmonary embolism, shortness of breath and acute pain.

Other signs of cardiogenic shock include vascular and autonomic reactions that develop as a result of a decrease in blood pressure. Cold sweat, paleness followed by blueness of the nails and lips, as well as severe weakness are also symptoms of cardiogenic shock. There is often a feeling of intense fear. Due to the swelling of the veins, which occurs after the heart stops pumping blood, the jugular veins of the neck become swollen. With thromboembolism, cyanosis occurs quite quickly, and marbling of the head, neck and chest is also noted.

In cardiogenic shock, loss of consciousness may occur after breathing and cardiac activity ceases.

First aid for shock

Timely medical assistance in case of severe injury and injury can prevent the development of a state of shock. The effectiveness of first aid for shock largely depends on how quickly it is provided. First aid for shock is to eliminate the main causes of the development of this condition (stopping bleeding, reducing or relieving pain, improving breathing and cardiac activity, general cooling).

Thus, first of all, in the process of providing first aid for shock, one should address the causes that caused this condition. It is necessary to free the victim from the rubble, stop the bleeding, extinguish burning clothing, neutralize the damaged part of the body, eliminate the allergen, or provide temporary immobilization.

If the victim is conscious, it is recommended to offer him an anesthetic and, if possible, drink hot tea.

In the process of providing first aid for shock, it is necessary to loosen tight clothing on the chest, neck or belt.

The victim must be placed in such a position that the head is turned to the side. This position allows you to avoid retraction of the tongue, as well as suffocation with vomit.

If shock occurs in cold weather, the victim should be warmed up, and if in hot weather, he should be protected from overheating.

Also, in the process of providing first aid for shock, if necessary, the victim’s mouth and nose should be freed from foreign objects, after which closed heart massage and artificial respiration should be performed.

The patient should not drink, smoke, use heating pads or hot water bottles, or be alone.

Attention!

This article is posted for educational purposes only and does not constitute scientific material or professional medical advice.

Make an appointment with a doctor

Shock can be caused by a condition in the body when blood circulation is dangerously reduced, for example, with cardiovascular disease (heart attack or failure), with large loss of blood (severe bleeding), with dehydration, with severe allergic reactions or blood poisoning (sepsis).

Shock classification includes:

Shock is a life-threatening condition and requires immediate medical treatment; emergency care is not excluded. The patient's condition in shock can quickly deteriorate; be prepared for initial resuscitation efforts.

Symptoms

Symptoms of shock may include feelings of fear or agitation, bluish lips and nails, chest pain, confusion, cold clammy skin, decreased or stopped urination, fainting, low blood pressure, pallor, excessive sweating, rapid pulse, shallow breathing, unconsciousness, weakness .

What can you do

First aid for shock

Check the victim's airway and perform artificial respiration if necessary.

If the patient is conscious and has no limbs or back, lay him on his back, with his legs raised 30 cm; don't raise your head. If the patient has suffered an injury in which raised legs cause pain, then there is no need to raise them. If the patient has received severe damage to the spine, leave him in the position in which you found him, without turning him over, and provide first aid by treating wounds and cuts (if any).

The person should stay warm, loosen tight clothing, and do not give the patient anything to eat or drink. If the patient is drooling or drooling, turn his head to the side to ensure the drainage of vomit (only if there is no suspicion of spinal injury). If there is still a suspicion of spinal injury and the patient is vomiting, it is necessary to turn him over, fixing his neck and back.

Call an ambulance and continue to monitor vital signs (temperature, pulse, respiratory rate, blood pressure) until help arrives.

Preventive measures

Preventing shock is easier than treating it. Prompt and timely treatment of the underlying cause will reduce the risk of developing severe shock. First aid will help control the state of shock.

Shock is a syndrome complex based on inadequate capillary perfusion with reduced oxygenation and impaired metabolism of tissues and organs.

A number of pathogenetic factors are common to various shocks: first of all, low cardiac output, peripheral vasoconstriction, microcirculation disorders, and respiratory failure.

CLASSIFICATION OF SHOCKS(according to Barrett).

I - Hypovolemic shock

1 – due to blood loss

2 – due to predominant loss of plasma (burns)

3 – general dehydration (diarrhea, uncontrollable vomiting)

II – Cardiovascular shock

1 – acute cardiac dysfunction

2 – heart rhythm disorder

3 – mechanical blockage of large arterial trunks

4 – decrease in reverse venous blood flow

III – Septic shock

IV – Anaphylactic shock

V - Vascular peripheral shock

VI - Combined and rare forms of shock

Heatstroke

Traumatic shock.

Hypovolemic shock - acute cardiovascular failure, which develops as a result of a significant deficiency of blood volume. The reason for the decrease in blood volume may be loss of blood (hemorrhagic shock), plasma (burn shock). As a compensatory mechanism, the sympathetic-adrenal system is activated, the level of adrenaline and norepinephrine increases, which leads to selective narrowing of blood vessels in the skin, muscles, kidneys, and intestines, provided that cerebral blood flow is maintained (blood circulation is centralized).

The pathogenesis and clinical manifestations of hemorrhagic and traumatic shock are in many ways similar. But with traumatic shock, along with blood and plasma loss, powerful streams of pain impulses come from the damaged area, and intoxication of the body with decay products of injured tissue increases.

When examining the patient, attention is drawn to the pallor of the skin, which is cold and damp to the touch. The patient's behavior is inappropriate. Despite the severity of the condition, he may be agitated or too calm. The pulse is frequent and soft. Blood pressure and central venous pressure are reduced.

Due to compensatory reactions, even with a decrease in blood volume by 15-25%, blood pressure remains within normal limits. In such cases, you should focus on other clinical symptoms: pallor, tachycardia, oliguria. Blood pressure level can serve as an indicator only if the patient is monitored dynamically.

The erectile and torpid phases of shock are noted.

The erectile phase of shock is characterized by pronounced psychomotor agitation of the patient. Patients may be inadequate, they fuss and scream. Blood pressure may be normal, but tissue circulation is already impaired due to its centralization. The erectile phase is short-lived and rarely observed.

In the torpid phase there are 4 degrees of severity. When diagnosing them, the Aldgover shock index is informative - the ratio of pulse rate to systolic pressure.

In case of first degree shock, the patient is conscious, the skin is pale, breathing is rapid, moderate tachycardia, blood pressure is 100-90 mm Hg. Index A. is almost 0.8-1. The approximate amount of blood loss does not exceed 1 liter.

In case of shock, stage II. – the patient is lethargic, the skin is cold, pale, moist. Shallow breathing, shortness of breath. Pulse up to 130 per minute, systolic D is 85-70 mm Hg. Index A.-1-2. The approximate amount of blood loss is about 2 liters.

In case of shock, stage III. – depression of consciousness, pupils are dilated, react sluggishly to light, pulse up to 110 per minute, systolic D does not exceed 70 mm Hg. Index A. – 2 and higher. Approximate blood loss is about 3 liters.

In case of shock IU stage. – (blood loss more than 3 liters) – terminal condition, consciousness is absent, pulse and blood pressure are not determined. Breathing is shallow and uneven. The skin has a grayish tint, is cold, covered with sweat, the pupils are dilated, there is no reaction to light.