shock
Introduction
Introduction to shock Shock is a clinical syndrome caused by insufficient acute tissue perfusion. It is a common complication in clinical serious diseases. The common feature of shock is that the effective circulation is insufficient. The blood perfusion of tissues and cells is severely limited by compensation, resulting in poor blood perfusion of whole body tissues and organs, resulting in hypoxia, microcirculation, and organ visceral organs. A series of pathophysiological changes such as dysfunction and abnormal metabolism of cells. Therefore, the onset of shock generally develops from compensatory hypotension (reduced tissue perfusion) to microcirculatory failure, which ultimately leads to cell membrane damage and cell death. The main clinical manifestations are blood pressure drop, systolic blood pressure reduced to below 12kPa (90mmHg), pulse pressure difference less than 2.67kpa (20mmHg), pale complexion, wet limbs and limbs purpura, superficial vein collapse, weak pulse, general weakness Reduced urine output, irritability, unresponsiveness, confusion, and even coma. basic knowledge Sickness ratio: 0.1% Susceptible people: no specific population Mode of infection: non-infectious Complications: acute respiratory failure, heart failure, acute renal failure
Cause
Shock cause
There are many reasons for shock, and there are many methods for classification. From the clinical point of view, shock can be divided into: according to its etiology and pathophysiological characteristics:
Cardiogenic shock (30%):
Cardiac shock narrowly refers to the severe stage of acute myocardial infarction pump failure (see acute myocardial infarction). In acute myocardial infarction, clinically accompanied by decreased blood pressure, insufficient skin perfusion, decreased renal blood flow, and central nervous system. Hypothyroidism caused by neurological dysfunction and other important organs, but can also exclude drugs (such as analgesics, vasodilators, diuretics), low intake of food, loss of body fluids or insufficient fluid replacement caused by hypovolemia. You can consider the diagnosis of cardiogenic shock.
Cardiac shock in a broad sense also includes acute myocarditis, massive pulmonary infarction, papillary muscle or chordae rupture, leaflet perforation, severe aortic valve or pulmonary stenosis with mild or moderate tachycardia, acute pericardial tamponade, tension Sexual pneumothorax, atrial myxoma, severe mitral or tricuspid stenosis with mild or moderate tachycardia, sustained tachycardia and other shocks.
Hypovolemic shock (15%):
Hypovolemic shock is a large amount of blood loss (internal or external bleeding) in the body or blood vessels, loss of water (such as vomiting, diarrhea, intestinal obstruction, gastrointestinal fistula, diabetic acidosis, etc.), loss of plasma (such as extensive burns, Shock caused by sudden decrease in blood volume due to peritonitis, trauma and inflammation, etc., characterized by decreased venous pressure, increased peripheral vascular resistance and tachycardia, hemorrhagic shock, traumatic shock and burn shock are all hypovolemic Sexual shock (see "Upper gastrointestinal bleeding").
Infectious shock (15%):
Septic shock, also known as toxic shock, is characterized by insufficient perfusion of tissue, usually caused by Gram-negative bacilli infection, and its circulatory insufficiency is due to increased peripheral vascular resistance, stasis of blood flow in the microcirculation, and cardiac output. Reduced and tissue hypoxia (a few are reduced vascular resistance, small movements, open venous short circuit, cardiac output does not decrease or even increase, but microcirculation perfusion is reduced), the cause is mainly seen in Gram-negative bacilli infection (such as Sepsis, peritonitis, necrotizing cholangitis, etc.), toxic bacillary dysentery, toxic pneumonia, fulminant epidemic cerebrospinal meningitis, epidemic hemorrhagic fever, etc.; shock is not caused by direct invasion of bacteria into the bloodstream, but with bacteria Endotoxin and its cell wall lipopolysaccharide are released into the blood, especially in patients with frail, aging, malnutrition, diabetes, malignant tumors and long-term use of hormones, immunosuppressive drugs and antimetabolites. "Infectious shock").Anaphylactic shock (10%):
Anaphylactic shock is a rare type of shock in which the body develops an allergic reaction to certain biological products, drugs or animal and plant allergens. Allergens and antibodies act on sensitized cells, the latter releasing The serotonin, histamine, bradykinin and other substances cause peripheral vasodilatation, capillary bed enlargement, plasma exudation, relatively insufficient blood volume, plus often throat laryngeal, bronchospasm caused by dyspnea, making the chest cavity The internal pressure is increased, so that the amount of blood returning to the heart is reduced, and the amount of blood discharged from the heart is also reduced (see "Allergic shock").
Neurogenic shock (20%):
Neurogenic shock is a serious disorder of arterial resistance regulation, loss of vascular tone, causing vasodilation, resulting in decreased peripheral vascular resistance, shock caused by reduced circulating blood volume, and shock caused by neurological factors alone, which can be seen in trauma, drama Pain, cerebrospinal injury, drug anesthesia, intravenous barbiturates, ganglion blockers or other antihypertensive drugs, and trauma.
Others have endocrine insufficiency (adrenal insufficiency, hypothyroidism, etc.) and endocrine hyperactivity (such as thyroid crisis, hyperparathyroidism, carcinoid and primary aldosteronism, etc.) shock.
Clinically, septic shock, cardiogenic shock, hypovolemic shock, and anaphylactic shock are more common.
Prevention
Shock prevention
1. Comprehensive prevention measures should be taken for the prevention of shock. For the wounded and sick people who may have shock, the corresponding preventive measures should be taken for the cause, and the wounded and sick should be promptly and accurately treated. The active bleeding should stop the bleeding. The fracture site should be securely fixed; the soft tissue injury should be bandaged to prevent contamination; the airway obstruction should be tracheotomy; if it needs to be delivered, it should be sent before and after the shock, and the fast and comfortable transportation means should be used. To the rear of the car or the tail of the aircraft, to prevent mid-brain anemia, continue to infusion during the delivery, and prepare for first aid.
2, severely infected patients, using sensitive antibiotics, intravenous drip, and actively remove the primary lesions (such as drainage and drainage), for some surgical diseases that may be complicated by shock, grasp the preoperative preparation, surgery within 2 hours, such as necrosis Intestinal section resection.
3, must fully prepare the surgical patients before surgery, including correction of water and electrolyte disorders and hypoproteinemia; make up the blood volume; comprehensive understanding of visceral function; choose the appropriate anesthesia method, but also fully estimate the possible shock during surgery Various factors, take appropriate measures to prevent hypovolemic shock.
4. In summary, it can be summarized as actively eliminating the cause and improving the body's ability to adjust and compensate.
Complication
Shock complications Complications acute respiratory failure heart failure acute renal failure
Complications such as heart failure, acute respiratory failure, acute renal failure, brain dysfunction and acute liver failure can occur.
Symptom
Shock symptoms Common symptoms No urine expression Apathy weakness Respiratory failure Hairy lips and nail bed slightly blue-violet hypotension shock Skin pale and unresponsive
As a clinical syndrome, the diagnosis of shock is often based on clinical manifestations of hypotension, poor microcirculatory perfusion, and sympathetic compensatory hyperactivity.
Diagnostic conditions:
1 has the cause of shock;
2 abnormal consciousness;
3 pulse faster than 100 times / min, fine or can not be touched;
4 limbs wet and cold, sternum skin pressure positive (after filling and refilling time is more than 2 seconds), skin pattern, pale or blemishes, urine volume less than 30ml / h or no urine;
5 systolic pressure is less than 10.64kPa (80mmHg);
6 pulse pressure is less than 2.66kPa (20mmHg);
7 The original systolic blood pressure of the original hypertension decreased by more than 30% compared with the original level. Any one that meets 1, and 2, 2, 3, 4, and 5, 6, 7 can establish a diagnosis.
(1) Early shock: the patient is conscious, but irritated, anxious or excited, pale and pale skin, lips and nail bed slightly bluish, cold sweat, cold limbs, nausea, vomiting, rapid heartbeat, pulse is still powerful The systolic blood pressure may be low or close to normal, or may be high due to increased secretion of catecholamines, but unstable; diastolic blood pressure is increased, so the pulse pressure is reduced and the urine volume is also reduced.
(B) mid-shock: clinical manifestations vary with the degree of shock, generally in moderate shock, in addition to the above performance, the mind is still clear, but weak, weak expression, indifferent, unconscious, blurred consciousness, pulse speed, press slightly Disappeared, systolic blood pressure dropped below 10.6 kPa (80 mmHg), pulse pressure was less than 2.7 kPa (20 mmHg), superficial vein collapsed, thirst, urine volume decreased to below 20 ml per hour, severe shock, shortness of breath, can fall into a coma State, the systolic pressure is below 8 kPa (60 mmHg), and even no measurement, no urine.
(3) Late stage of shock: diffuse intravascular coagulation and extensive cardiac organic damage occur in this period, the former causes bleeding, skin, mucous membrane and visceral bleeding, gastrointestinal bleeding and hematuria are more common; adrenal hemorrhage can lead to acute Adrenal cortical failure; pancreatic hemorrhage can lead to acute pancreatitis, heart failure, acute respiratory failure, acute renal failure, brain dysfunction and acute liver failure.
Examine
Shock check
(1) Blood routine: After a large number of bleeding, red blood cells and hemoglobin are significantly reduced; in patients with water loss, blood concentration occurs, red blood cell count increases, hematocrit increases, white blood cell count generally increases, and most infected people have white blood cell counts and Significant increase in neutrophils, decreased eosinophils, bleeding tendency and disseminated intravascular coagulation, reduced platelet count, decreased fibrinogen, prolonged prothrombin time, plasma protamine coagulation Test (3P test) or ethanol glue test positive.
(2) Blood chemistry: blood sugar is increased, blood pyruvic acid and lactic acid are increased, and the pH value is lowered, the alkali reserve is lowered, the carbon dioxide binding force is lowered, and the blood urea nitrogen and non-protein nitrogen are increased when the renal function is reduced, and the blood potassium is also It can be increased, blood transaminase, lactate dehydrogenase, etc. can be increased when liver function is reduced, blood ammonia can be increased in liver function failure, arterial oxygen saturation, venous blood oxygen content can be decreased, arterial oxygen partial pressure is significant in pulmonary failure Reduced, pure oxygen can not return to normal.
(3) Urine routine: Protein, red blood cells and casts may appear in the urine as the kidney changes.
(4) Electrocardiogram: There may be obvious manifestations of insufficient blood supply to the coronary arteries. For example, the ST segment is decreased, the T wave is low or inverted, and even a myocardial infarction may be changed. The original heart disease may also have a corresponding ECG change.
[Auxiliary inspection]
(1) Measurement of arterial pressure: In addition to the early stage of shock, the arterial pressure of the patient is reduced. Sometimes, when the blood pressure is measured by the cuff sphygmomanometer, the blood pressure has been significantly decreased or not detected, but the patient is generally in good condition and the urine volume is not significantly reduced. If you use the intra-arterial direct pressure measurement method, you can find that the blood pressure is not significantly reduced or even normal. This is because the surrounding blood vessels contract and the cuff pressure measurement is unreliable. Therefore, in the application of the pressure-boosting drug, Cuff pressure measurement as an indicator may cause excessive use of the booster drug, but increase the burden on the heart. Therefore, while measuring blood pressure, the patient's general condition, such as pulse rate, consciousness, skin color and temperature of the limbs, urine volume, etc., should be closely observed. For comprehensive analysis and judgment, if conditions are available, it is best to measure arterial pressure directly by arterial puncture cannula. In addition, blood pressure should be measured in normal children with lower blood pressure than adults; in those with high blood pressure, blood pressure values decrease by more than 20% or Compared with the original blood pressure lower than 4kPa (30mmHg), it should be considered that the blood pressure has been reduced, the local swelling of the limb at the pressure measuring site, the compression of the artery, or the local blood pressure caused by local pressure is not smooth, etc. Correctness of blood pressure, the measurement site should be replaced.
(B) central venous pressure measurement: measurement of central venous pressure, help to identify shock caused by cardiac insufficiency or hypovolemia, so deal with all types of shock, determine the quality and quantity of infusion, whether to use cardiotonic or diuretic There is a certain guiding significance. When measuring, a plastic tube is passed through the peripheral vein into the upper or lower atrium of the superior or inferior vena cava via a venous puncture. The catheter is filled with normal saline or 5% glucose solution, and a little is added. Heparin, which is connected to the Y-shaped tube, can be used as a fluid replacement channel when no pressure is measured. When the pressure is measured, the breathing should be suspended. The fourth intercostal space of the midline is "0", and the central venous pressure is proportional to the right ventricular filling pressure. In the absence of pulmonary circulation or right ventricular disease, it can also indirectly reflect left ventricular end-diastolic pressure, which can reflect the heart's ability to load the infusion, but there are many factors affecting central venous pressure, such as vasoconstrictors and dilators. Application, lung disease, heart disease, and inaccuracy of the "0" level should be noted.
(3) Pulmonary wedge embedding pressure measurement: Pulmonary wedge embedding pressure reflects the left atrial mean pressure, which is closely related to left ventricular end-diastolic pressure. Pulmonary wedge pressure is measured in the absence of pulmonary vascular disease or mitral valve disease, which helps to understand left Ventricular function is a good indicator for estimating blood volume and monitoring infusion rate to prevent pulmonary edema. In recent years, a floating heart catheter with a balloon (Swan-Ganz catheter) has been widely used, through the surrounding vein, It is sent to the upper or lower atrium of the superior or inferior vena cava, and the balloon is injected with 1.0 to 1.5 ml of carbon dioxide or air. After the balloon is inflated, it can float into the pulmonary artery branch with the blood flow (without fluoroscopy), when the balloon is deflated Pulmonary arterial pressure can be recorded; after the balloon is inflated again, the pulmonary artery is blocked, and the pulmonary wedge compression can be recorded at this time.
(4) Determination of cardiac output: using a floating heart catheter with a thermistor, the top of the cardiac catheter is placed in the pulmonary artery, and the opening for injecting the liquid is placed in the right atrium, and some blood is first extracted to make the cardiac catheter cavity of the external part. The temperature inside is increased to the level of body temperature, and 10 ml (or 5% glucose solution) of cold physiological saline at a temperature of 0.5 ° C is rapidly injected from the catheter lumen, and the number of cardiac output is displayed by a measuring instrument having an electronic computing device. Repeatedly and quickly.
At present, the application of multi-purpose floating heart catheter can simultaneously measure central venous pressure, pulmonary wedge compression, pulmonary artery pressure and cardiac output. If the catheter has a platinum electrode, the intracardiac electrocardiogram or intracardiac pacing can be recorded if necessary. , the general catheter placement time can not exceed 72 hours.
(5) Determination of urine volume: Incontinence catheter is continuously observed for urination, and the urine volume per hour is required to be more than 20 to 30 ml. If it is less than this, it indicates that the renal blood flow is insufficient and the renal function tends to be exhausted.
(6) Microcirculation perfusion inspection:
1, skin and anus temperature measurement: skin vasoconstriction during shock, so the skin temperature is often low; because the skin vasoconstriction can not dissipate heat, so the anus temperature often increases, such as the temperature difference between 1 ~ 3 ° C, it means shock Severe (normal at around 0.5 °C).
2. Hematocrit: When the hematocrit of peripheral peripheral blood is higher than 3 Vol% of the central venous hematocrit, it indicates significant peripheral vasoconstriction. The magnitude of this change often indicates that microcirculation perfusion is worsening or improving. Degree.
3, fundus and nail bed examination: fundus examination can be seen small arteriolar spasm and venule dilatation, severe retinal edema, can be seen in the capillary after the pressure on the nail to relax the blood filling time.
Diagnosis
Shock diagnosis
diagnosis
In the case of typical clinical manifestations, the diagnosis of shock is not difficult, it is important to find and deal with it in the early stage.
Early diagnosis
When there is a sign of sympathetic-adrenal hyperfunction, the possibility of shock should be considered. Early symptom diagnosis includes: 1 high blood pressure and decreased pulse pressure difference 2 heart rate increased fast 3 thirst 4 skin moist, mucous membrane whitish, cold extremities 5 skin vein collapse 6 urine volume decreased (25 ~ 30ml / L).
2. Diagnostic criteria
The clinical diagnostic criteria for shock for many years are: 1 There is a cause of shock. 2 conscious obstacles. 3 pulse fine speed, more than 100 times / minute or can not be touched. 4 The limbs are wet and cold, and the skin pressure of the sternum is positive (the filling time is more than 2 seconds after compression), the skin has a pattern, the mucous membrane is pale or blemish, the urine volume is less than 30ml/h or the urine is closed. 5 systolic blood pressure is lower than 10.7 kPa (80 mmHg). The 6-pulse pressure difference is less than 2.7 kPa (20 mmHg). 7 original hypertension, systolic blood pressure decreased by more than 30% compared with the original level. Any one of the above items 1 and 2, 3, 4 and 5, 6, and 7 may be diagnosed as shock.
Differential diagnosis
Cardiac shock, anaphylactic shock, and hypovolemic shock were identified.
