Pediatric shock

Introduction to pediatric shock Shock is an acute clinical syndrome caused by a variety of causes of vital circulatory perfusion, leading to tissue ischemia, hypoxia, metabolic disorders and organ dysfunction. Effective circulating blood loss is a different cause. The common pathophysiological basis of shock, as one of the more common critical illnesses in clinical practice, people's research and understanding of the pathogenesis of shock is increasing, from microcirculation theory to the development of various stages of shock and cell and molecular level. In-depth research has made great progress and guided clinical practice, laying a necessary foundation for improving the success rate of rescue and improving the prognosis. basic knowledge The proportion of illness: 0.02% Susceptible people: children Mode of infection: non-infectious Complications: bloating, digestive tract bleeding, coma, jaundice, metabolic acidosis

Pediatric shock cause

(1) Causes of the disease

According to different causes, shock is generally classified into septic shock, anaphylactic shock, hypovolemic shock, cardiogenic shock and neurogenic shock.

Infectious shock

Also known as septic shock, mainly caused by bacteria, viruses and other pathogenic microorganisms and their harmful products, Gram-negative bacteria infection is the first, children with septic shock pathogens vary with age and immune status, new students In childhood, group B hemolytic streptococcus, enterobacteriaceae, listeria monocytogenes, Staphylococcus aureus and meningococcus are the main causes; Haemophilus influenzae, pneumococcus, commonly found in infancy Staphylococcus aureus and meningococcus; in childhood, pneumococcal, meningococcus, staphylococcus aureus and enterobacteriaceae are common, and common pathogens causing septic shock in immunocompromised are Enterobacteriaceae , Staphylococcus aureus, Pseudomonadaae and Candida albicans, causing septic shock, the main infections are sepsis, epidemic cerebrospinal meningitis, toxic dysentery, necrotizing enteritis, severe pneumonia and urinary tract Infection, in addition, intestinal mucosal barrier dysfunction due to infection or other factors, causing intestinal bacteria and endotoxin or other enterotoxin to pass through the intestine Intestinal mucosa resulting in transfer of the bacteria or gut-derived sepsis, is one cause of septic shock, in recent years, viral infection viremia with shock there is an increasing trend.

2. anaphylactic shock

It is caused by allergies to certain drugs, serum preparations or foods. Penicillin, tetanus antitoxin, some seafood, pineapple, nut foods such as peanuts, and medlar are all common allergenic substances.

3. Hypovolemic shock

Due to the sharp decrease in blood volume, resulting in decreased cardiac output and blood pressure, severe dehydration caused by vomiting and diarrhea in infants and young children is an important cause of pediatric causes of hypovolemic shock caused by sharp decrease in blood volume. Other common causes are trauma. Caused by a large number of blood loss, extravasation of plasma in severe burns, major bleeding in the digestive tract and other bleeding disorders caused by blood clotting disorders.

4. Cardiogenic shock

It is caused by acute blood dysfunction of the heart, resulting in insufficient blood perfusion of tissues and organs. Common causes include congenital heart disease, fulminant myocarditis, severe arrhythmia, pericardial tamponade and acute pulmonary infarction. Asphyxia is an important cause of cardiogenic shock in the neonatal period.

5. Neurogenic shock

Severe pain caused by trauma, etc., causes small blood vessels to dilate, blood stasis, and effective circulation of blood to reduce shock.

(two) pathogenesis

Different types of shock have different causes and pathogenesis, but the effective circulating blood volume is the common pathophysiological basis. The effective circulating blood volume decreases, the cardiac output decreases and the microcirculatory disorder is the occurrence of shock. Basic link.

Infectious shock

Its occurrence, development is affected by many factors, endotoxin can be used as a trigger for shock, leading to microcirculation, blood clotting, fibrinolysis system dysfunction, release of a large number of inflammatory mediators, cell function damage, and even vital organ failure.

(1) release of inflammatory mediators and their damage: endotoxin and tissue ischemia and hypoxia stimulate the body to release a large number of inflammatory mediators, such as tumor necrosis factor, interleukin, granulocyte-monocyte stimulating factor and platelet activating factor. , causing systemic inflammatory response syndrome (SIRS), and can develop into multiple system organ failure syndrome; prostacyclin (PGI2) and thromboxane A2 (thromboxane, TXA2) can affect vascular permeability Sexuality and strong vasoconstriction, promote platelet aggregation and thrombosis, and become an important cause of shock development; increased beta-endorphin release can inhibit cardiac function, resulting in decreased cardiac output; catecholamine secretion, causing renal arteriolar spasm, activation of kidney The angiotensin-aldosterone system causes vasoconstriction, myocardial ischemia, and aggravation of microcirculatory disorders; histamine increases the permeability of small blood vessels, exudates plasma, and reduces circulating blood volume.

(2) Free radical damage: In shock, the body's superoxide dismutase, catalase and other scavenging free radicals, the protective effect on the body is weakened, so that the free radicals increase excessively and damage the body.

(3) Fibronectin (Fn): When shock is reduced, the concentration of plasma Fn decreases, the adhesion between the vascular endothelium is reduced, the integrity of the vessel wall is impaired, the permeability is increased, the plasma is exuded, and the blood is concentrated. The effective circulation of blood is more reduced.

(4) Large influx of calcium ions: When shock occurs, the cell function is impaired. Calcium ions are driven by the difference in concentration inside and outside the cell, and a large amount flows into the cells, causing the protein and fat to be destroyed, producing a large amount of free fatty acids, inhibiting Mitochondrial function, causing irreversible damage to cells.

The common result of the above aspects is vascular endothelial injury, increased permeability, microthrombus formation, microcirculatory disorder, insufficient circulating blood volume, tissue hypoxia and a vicious circle, and then developed into diffuse intravascular coagulation (DIC). And multiple organ failure (MOF).

2. anaphylactic shock

When the external antigen substance enters the body and reacts with the corresponding antibody, it releases a large amount of histamine, bradykinin, serotonin and platelet activating factor, causing systemic telangiectasia, increased permeability, plasma oozing, and a significant decrease in circulating blood volume. The blood pressure drops.

3. Hypovolemic shock

Due to a large number of blood loss, loss of fluid and plasma loss, the blood volume is drastically reduced, the blood volume of the heart is decreased, and the cardiac output is seriously insufficient.

4. Cardiogenic shock

Due to acute cardiac dysfunction, cardiac output is reduced, microcirculatory disturbances, insufficient blood perfusion in important organs, early shock, due to the mechanism of compensation, peripheral vasoconstriction, increased cardiac afterload, and further decreased cardiac output. As the disease continues to worsen, acidic metabolites accumulate, capillaries expand, causing blood stasis, tissue organ perfusion is reduced, and organ function is severely impaired.

5. Neurogenic shock

Due to severe pain and other stimuli, it causes the release of bradykinin, serotonin, etc., causing vasodilation, microcirculation and congestion, which reduces the effective circulating blood volume and lowers blood pressure.

Pediatric shock prevention

Mainly to prevent various causes of shock, active diagnosis and treatment of primary diseases, such as control of infection, sepsis, dehydration, allergic reactions, myocardial damage, arrhythmia, tension pneumothorax, severe anemia, etc., if timely control of the above conditions and promote Recovery can effectively prevent the occurrence of shock.

Pediatric shock complications Complications, abdominal distension, gastrointestinal bleeding, coma, jaundice, metabolic acidosis

With the evolution of the disease, the signs of MOF may appear further, affecting the lungs, gastrointestinal tract, brain, kidney, heart and liver, showing respiratory distress, severe hypoxemia and hypercapnia, abdominal distension, weakened bowel sounds, Gastrointestinal hemorrhage, mental apathy, coma, oliguria or anuria, elevated blood urea nitrogen, elevated serum creatinine, heart failure, increased myocardial isoenzymes, enlarged liver, jaundice, elevated serum bilirubin, Decreased albumin, etc., circulatory failure, metabolic acidosis, late stage may have DIC manifestations.

Symptoms of pediatric shock Common symptoms Pale pale hair stun stun blood pressure drop consciousness loss skin wet cold heart rate increase circulatory failure consciousness disorder dyspnea

1. Clinical manifestations: The clinical manifestations of shock caused by different causes have certain overlap and commonality.

(1) Early shock: manifested as respiration and heart rate, the degree is not parallel with the increase of body temperature; poor response, mild irritability; warm skin of the extremities and whole body, normal or slightly lower blood pressure, may have systemic inflammatory response Such as: fever, increased white blood cells, increased proportion of neutrophils and toxic particles.

(2) In shock, late: pale, cold limbs, weak pulse, reduced urine output, severe hypoxia and circulatory failure: such as shortness of breath, cleft lip, irritability, disturbance of consciousness, arterial oxygen partial pressure Decreased, blood oxygen saturation decreased, metabolic acidosis; heart rate increased, limbs and skin wet and cold, pattern appeared.

Body temperature: body surface temperature is a relatively simple and effective indicator for monitoring peripheral perfusion. The skin temperature of the whole body is low, suggesting that shock is in a serious state. Some research data show that the difference between the temperature of the toe end and the outside temperature is better than 4 °C. If the temperature between the toe end and the outside temperature is between 1 and 2 °C, the prognosis is dangerous.

Blood pressure: Blood pressure is an important indicator of shock monitoring. Especially, the pulse pressure difference is very valuable for estimating cardiac output. The pulse pressure difference is reduced, indicating that the ventricular ejection function is decreased, and the peripheral resistance is increased. When the pulse pressure difference is <20mmHg, the prompt Insufficient cardiac output, lower blood pressure, systolic blood pressure below 40mmHg, decreased urine output or no urine, and DIC in late stage.

2. Cardiogenic shock: There are still symptoms and signs of the primary disease, such as supraventricular paroxysmal tachycardia, heart rate up to 250 beats / min, with a history of paroxysmal episodes and changes in cardiogram, pericardium The tamponade has signs of jugular vein engorgement, strange veins and distant heart sounds. Allergic shock can cause dyspnea due to laryngeal edema, shortness of breath, chest tightness, cyanosis, severe suffocation, cerebral hypoxia-induced cerebral edema Loss of consciousness, convulsions and coma.

3. Infectious shock: According to the severity of the clinical condition, it is divided into 2 types.

Pediatric shock examination

Laboratory inspection

Blood test

White blood cell counts and neutrophils were significantly increased, and platelets decreased significantly.

Blood gas analysis, blood lactate determination, hypoxemia and hyperlacticity.

Blood gas analysis: monitoring the acid-base balance state and oxygen transport in the body is an indispensable monitoring item in the treatment of shock, PaO2 <60mmHg or PaO2/FiO2<300.

Determination of blood lactic acid: reflecting the condition of microcirculation and metabolism during shock, it is meaningful for judging prognosis. The degree of elevation is closely related to the mortality rate. The blood lactic acid content is often >2mmol/L during shock, timely and effective treatment to improve organ perfusion. In the case, blood lactate levels can be reduced within 1 hour.

Prolonged prothrombin time, abnormal liver function, abnormal renal function, elevated transaminase, decreased albumin, bilirubin>34mol/L; creatinine>176.8mol/L, increased urea nitrogen, increased serum potassium, hyperglycemia.

2. Urine check

Changes in urine output and proteinuria, urine volume reflects organ perfusion, which is helpful for early diagnosis and evaluation of organ perfusion improvement after treatment. It is usually recorded once every hour, urine volume <0.5ml/(kg·h) For oliguria.

3. Pathogen inspection

Children with insignificant symptoms should be given blood, urine routine and blood, secretion culture, direct smear and other tests to confirm the infection. Now there are also specific antigen methods such as latex agglutination test for determining the cell wall of pathogenic bacteria. Enzyme-linked immunosorbent assay, etc., can identify pathogens in a short period of time, and endotoxin measurement can help diagnose Gram-negative bacteria infection, and conditions can also be carried out.

4. Determination of gastric intramucosal pH (pH1)

The literature reports that the mortality rate of children with shock is lower than 7.3, and the mortality rate increases. With the further improvement of equipment and technology, it is expected to become the gold standard for evaluating the circulation status and recovery effect of patients with septic shock.

In the case of shock, in addition to blood gas analysis, blood lactate determination, urine output and other monitoring items, you can also choose central venous pressure, pulmonary wedge pressure, cardiac output, etc. to guide clinical treatment, according to clinical choice X-ray, B-ultrasound , ECG, brain CT and other examinations.

Film degree exam

Echocardiography

It is a non-invasive, reproducible monitoring method for understanding cardiac contraction, diastolic function, presence or absence of pericardial effusion, and estimation of pulmonary artery pressure.

2. Central venous pressure (CVP)

CVP measurement can help to identify shock caused by cardiac insufficiency or hypovolemia, and provide a basis for determining whether it is necessary to supplement blood volume, determine the quality, quantity and speed of infusion, and whether it requires positive inotropic drugs. The normal value of CVP is 6 to 12 cm H2O.

3. Pulmonary artery wedge pressure (PAWP)

Can better reflect left ventricular function, normal value 8 ~ 12mmHg, <8mmHg, suggesting insufficient blood volume; >20mmHg, indicating left ventricular dysfunction, 26 ~ 30mmHg, suggesting severe pulmonary congestion; >30mmHg, often Pulmonary edema occurs.

Diagnosis and diagnosis of pediatric shock

Good monitoring is of positive significance in evaluating the condition of the child, guiding treatment and prognosis. The basic monitoring includes consciousness, heart rate, pulse, breathing, blood pressure, body temperature, urine volume, blood lactate content determination and blood gas analysis, etc., depending on the situation. Blood pressure, central venous pressure, pulmonary wedge pressure, gastrointestinal mucosal pH and echocardiographic monitoring were used.

1. Diagnosis of septic shock

Although the basic theoretical research of shock has been deepened and a basic understanding has been obtained, the early diagnosis of shock is still based on clinical observation and empirical judgment.

2. anaphylactic shock

(1) Have a history of exposure to allergens such as a history of medication or a bite of poisonous insects.

(2) Most sudden onset, the above clinical symptoms and signs appear soon.

(3) Laboratory examination showed that the white blood cell count was normal or increased, eosinophilia increased, urine protein was positive, serum IgE increased, and skin sensitivity test showed positive reaction, which may have ECG changes and chest X-ray changes.

3. Hypovolemic shock

It is caused by massive blood loss, dehydration, loss of plasma, etc., causing a sharp decrease in blood volume, and circulatory failure. Shock caused by major bleeding, also known as bleeding shock.

4. Cardiogenic shock

The clinical manifestations include the performance of primary disease and the performance of shock. Cardiogenic shock belongs to low-grade and high-resistance shock, and its clinical manifestations are basically the same as those of septic shock. If there is a mentality in children with heart pump dysfunction. Changes, peripheral circulation and capillary filling are not good, blood pressure drops, heart rate increases, pulse fine and other symptoms, should be highly alert to the occurrence of shock, close monitoring, timely treatment.

Shock caused by various causes depends on medical history, clinical manifestations and various laboratory-assisted examinations.

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