Shock

Introduction Shock is a clinically common emergency. It is caused by various pathogenic factors, causing a decrease in effective circulating blood volume, resulting in insufficient perfusion of various tissues and vital organs, resulting in a series of metabolic disorders, cell damage and organ dysfunction. Its clinical manifestations are pale, cold limbs, limbs, rapid pulse, decreased urine output, slow mentality, and decreased blood pressure. Shock is characterized by microcirculatory disorders, which can be encountered in various clinical departments. Regardless of its etiology, the underlying factor of shock is the sharp decrease in effective blood volume, which ultimately leads to tissue ischemia, hypoxia, abnormal cell metabolism, and cell death. Therefore, early diagnosis of shock, timely treatment, and active search for the cause, is of great significance for saving the lives of patients.

Cause

The classification of shock is mainly based on the etiology classification. Although there is no unified understanding of the shock classification, it is generally divided into three categories:

Hypovolemic shock

Hypovolemic shock is insufficient for vascular content, causing insufficient ventricular filling and decreased stroke volume. If the heart rate is increased, it cannot be compensated, which may lead to a decrease in cardiac output.

(1) Hemorrhagic shock: refers to a syndrome caused by a large amount of blood loss, which rapidly leads to a sharp decrease in effective circulating blood volume and causes peripheral circulatory failure. Generally, when the blood loss is less than 10% of the whole blood volume within 15 minutes, the body can be compensated. If the rapid blood loss exceeds 20% of the whole blood volume, it can cause shock.

(2) burn shock: large area burns, accompanied by a large loss of plasma, can cause burn shock. Early shock is associated with pain and hypovolemia, and advanced infection can progress to septic shock.

(3) Traumatic shock: The occurrence of this shock is related to pain and blood loss.

Vasodilator shock

This type of shock is usually due to insufficient blood vessel volume due to vasodilation, normal or increased circulating blood volume, but insufficient heart filling and tissue perfusion.

(1) Septic shock: It is one of the most common types of shock in clinical practice, and it is most common in clinical infection with G. faecalis. According to the characteristics of hemodynamics, there are two types: low-dynamic shock (cold shock) and high-dynamic shock (warm shock).

(2) Anaphylactic shock: When the sensitized body is exposed to the antigenic substance again, a strong allergic reaction may occur, causing the volume of blood vessels to dilate, capillary permeability to increase, and diffuse non-fibrin thrombosis, blood pressure drop, tissue Poor perfusion can involve multiple organs.

(3) Neurogenic shock: acute injury of the sympathetic nervous system or the small artery that is affected by the drug block may cause dilation of the small arteries, increased blood volume, and relative blood volume deficiency and blood pressure drop. This type of shock has a good prognosis and can often heal itself.

Cardiogenic shock

Such shock refers to an effective circulating hypovolemia, hypoperfusion, and hypotensive state caused by impaired cardiac pump function or rapid decline in cardiac output due to impaired cardiac blood flow discharge and insufficient contraction of rapidly compensated blood vessels. Cardiogenic shock includes shock caused by heart disease, heart compression or obstruction.

an examination

Related inspection

Blood stasis, conventional urine specific gravity, urinary methionine (Met), urinary myoglobin

1. Laboratory examination: The laboratory examination of shock should be carried out as soon as possible and pay attention to the extensiveness of the examination. Items that are generally noted include: 1 blood picture. 2 blood biochemistry (including electrolytes, liver function, etc.) examination and blood gas analysis. 3 renal function tests as well as urine routine and specific gravity. 4 out, coagulation indicators check. 5 serum enzymology and troponin, myoglobin, D-dimer and so on. 6 culture of various body fluids, excretions, etc., pathogen examination, and drug sensitivity measurement.

2, hemodynamic monitoring: mainly including central venous pressure (CVP), pulmonary capillary wedge pressure (PWAP), cardiac output (CO) and cardiac index (CI). When using a floating catheter for invasive monitoring, a mixed venous blood sample can also be taken for measurement, and the oxygen metabolism index can be calculated by calculation.

3, gastric mucosal pH measurement (pHi): This non-invasive detection technology helps to determine the visceral blood supply status, timely detection of early visceral ischemic manifestations of the "hidden compensatory shock", can also be accurately reflected Improvement of gastrointestinal mucosal ischemia and hypoxia, guiding the thoroughness of shock resuscitation treatment.

4. Serum lactic acid concentration: normal value 0.4 to 1.9 mmol/L. Serum lactate concentration is associated with a prognosis of shock.

5. Serological examination of infections and inflammatory factors: examination of procalcitonin (PCT), C-reactive protein (CRP), Candida or Aspergillus specific antigenic markers or antibodies and LPS by serum immunoassay Factors such as TNF, PAF, and IL-1 can help to quickly determine whether there are infectious factors, possible infection types, and inflammatory response disorders in the body.

Differential diagnosis

1, the identification of benign hypotension and shock

One of the important clinical manifestations of shock is hypotension, but all patients with hypotension may not be able to diagnose shock. Under physiological conditions, the normal range of blood pressure varies greatly. People of different ages, genders, and physiques may have different blood pressure normal values. It is generally believed that the adult brachial artery blood pressure is lower than 12/8 kPa (90/60 mmHg). Benign hypotension is a hypotension with no pathological changes in shock, which is essentially different from shock. Common benign hypotension mainly includes two types:

1) Constitutional hypotension: also known as primary hypotension, common in people with weak constitution, more women, may have a family genetic predisposition, generally no symptoms, mostly found in physical examination. The systolic blood pressure can be only 10.6 kPa (80 mmHg), but it has no important clinical significance. A few patients may experience mental fatigue, forgetfulness, dizziness, headache, and even syncope. There are also pre-cardiac pressure, palpitations and other similar cardiac neurosis. The performer. These symptoms can also be caused by chronic diseases or malnutrition, no organic lesions, heart rate is often unpleasant, microcirculation is well filled, no pale and cold sweat, normal urine output.

2) Orthostatic hypotension: It is caused by a change in body position, such as a sudden change from a supine position to an upright position, which can also be seen in standing for a long time. Severe orthostatic hypotension can cause syncope, and orthostatic hypotension can be idiopathic or secondary. The former may be an autonomic dysfunction, and the systolic dysfunction of the small arteries may be associated with a decrease in muscle tone. The patient may have a weak sense, but no sweat, may have incontinence, sudden onset, and no mental excitement. Obviously related to body position changes. The latter can be secondary to the effects of certain chronic diseases or certain drugs, with similar pathogenesis.

2, the identification of different types of shock

The diagnosis of different types of shock is directly related to the choice of treatment. Common types of shock include septic shock, anaphylactic shock and neurogenic shock, hypovolemic shock (hemorrhagic shock and traumatic shock), cardiogenic shock, and obstructive shock. The commonality of these shocks is abnormal hemodynamics. The key to identification is the cause of shock, the characteristics of shock, and the diagnostic treatment (responsiveness to treatment) for difficult-to-identify shock.

1) Infectious shock

1 confirmed and suspected infections, and hemodynamic changes are based on increased infection.

2 When the blood pressure drops, the cardiac output increases, the systemic vascular resistance decreases, and the diastolic blood pressure drops more significantly.

3 Simple fluid resuscitation can not effectively maintain hemodynamics, the body responds well to norepinephrine, and the urine volume increases significantly with the increase of blood pressure.

2) hypovolemic shock

1 There are in vitro and in vivo losses of effective blood volume. Common causes of in vitro loss are blood loss caused by open trauma, upper gastrointestinal bleeding. There are intracranial hemorrhage, intra-abdominal hemorrhage, post-peritoneal hemorrhage, massive ascites or pleural effusion, massive exudation of severe acute pancreatitis, and mechanical intestinal obstruction.

2 Both systolic and diastolic blood pressures can be reduced, while systolic blood pressure is reduced. Low body temperature, pale skin, cyanosis of the extremities, collapse of the jugular vein, thirst, oliguria or anuria, increased urine density, low or normal hematocrit.

3 Simple fluid resuscitation can quickly restore hemodynamics unless there is continuous loss of fluid or blood loss, and dopamine can be quickly stopped.

3) Cardiogenic shock

1 Cardiogenic shock is secondary to progressive deterioration of heart disease or acute heart disease (acute myocardial infarction, heart valve or ventricular septal rupture, etc.).

2 Bradycardia and arrhythmia lead to abnormal cardiac systolic function, decreased blood flow to the heart and decreased cardiac output. The main feature is low cardiac output with significant elevation of CVP and jugular venous engorgement. Not obvious.

3 Blood pressure rises rapidly after receiving treatment measures for cardiac abnormalities.

4) Obstructive shock

1 There are various reasons for the outflow of the heart and obstruction of the inflow channel, such as tension pneumothorax caused by chest penetrating trauma, pericardial tamponade, and superior and inferior vena cava obstruction.

2 Jugular vein engorgement is the most important feature, and the increase and decrease of CVP is related to the obstruction site.

3 Blood pressure can be quickly restored after surgical removal of the obstruction.

5) anaphylactic shock

1 There is a clear history of exposure to allergens such as drugs, food or insect bites in a short period of time before the onset of shock.

2 systemic allergic reactions: skin flushing, itching, urticaria, bloating, abdominal pain, nausea, vomiting, diarrhea, etc.

3 airway response: laryngeal edema, bronchospasm, bronchial hemorrhage, pulmonary edema.

4 The blood pressure was significantly improved after subcutaneous or intramuscular injection of adrenaline.

6) Neurogenic shock

1 Severe traumatic spinal cord injury, spinal anesthesia, regional block anesthetics, severe pain, high-dose analgesia, sedative drug application, etc., leading to loss of peripheral vasomotor regulation, blood retention in peripheral blood vessels, reduced venous return The cardiac output is reduced.

2 The skin above the plane of the spinal cord injury is warm, and the surface is cold. It can also be seen that the skin is pale, damp and cold, and the patient is highly nervous.

3 After rapid subcutaneous or intramuscular injection of epinephrine, blood pressure returned to normal.

7) Endocrine shock

1 There is a history of hypofunction of the anterior pituitary or a decrease in adrenal insufficiency (sudden withdrawal or severe stress after long-term administration of glucocorticoids).

2 The anti-shock measures such as catecholamines and infusions have poor reactivity and are often mixed with other types of shock.

3 After the administration of glucocorticoids, blood pressure quickly rose.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.