Septic shock

Introduction to septic shock Septic shock refers to shock caused by sepsis. In the past, it was called septic shock. It was defined as insufficient perfusion of tissue in patients, that is, continuous hypotension after volume test or blood lactate concentration 4mmol / L. Usually caused by Gram-negative bacilli, mainly seen in acute suppurative obstructive cholangitis, gangrenous cholecystitis, pyelonephritis, acute pancreatitis and some nosocomial infections. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: renal failure

Septic shock etiology

Pathogenesis and disease physiology

The pathogenesis of septic shock has not been fully elucidated, and bacterial toxins produced by infected bacteria can trigger complex immune responses, in addition to endotoxin (a lipid component in the lipopolysaccharide released by the cell wall of Gram-negative Enterobacter). There are also a large number of media, including tumor necrosis factor, leukotrienes, lipoxygenase, histamine, bradykinin, serotonin and interleukin-2.

The initial changes were arterial and arteriolar dilatation, decreased peripheral arterial resistance, and normal or increased cardiac output. When the heart rate is increased, the ejection fraction may decrease. Later, the cardiac output can be reduced and the surrounding resistance can be increased. Despite an increase in cardiac output, the function of blood flow into the capillaries is impaired, and the supply of oxygen and the removal of carbon dioxide and waste are reduced. This decrease in perfusion causes the kidneys and brain to be particularly affected, thereby causing one or more organs. Depletion. Eventually, the cardiac output is reduced and a typical shock characteristic occurs.

Susceptible population and susceptibility factors

Septic shock occurs in immunocompromised populations such as diabetes, cirrhosis, leukopenia, especially in patients with concurrent or cytotoxic drugs, patients using antibiotics, corticosteroids or artificial respiration devices, urinary tract, History of biliary or gastrointestinal infections, invasive implants including catheters, drainage tubes, and other foreign bodies. Septic shock is more common in neonates, patients over 35 years of age, pregnant women, or patients with severe immunocompromised by primary disease or iatrogenic complications.

Septic shock prevention

For the wounded and sick people who may have shock, the corresponding preventive measures should be taken according to the cause, severely infected patients, sensitive antibiotics, intravenous drip, and active removal of the primary lesions (such as draining pus).

Septic shock complications Complications, renal failure

Multiple organ failures including lung, kidney and liver occur.

Symptoms of septic shock Common symptoms Respiratory alkalosis Hypoxemia Myocardial infarction Metabolic acidosis Shock toxemia Hematuria Respiratory failure Hypotension Anal sphincter transection

Septic shock is distributed shock. The hemodynamic characteristics of the initial high kinetic state are characteristic of sepsis: normal or increased cardiac output and reduced peripheral arterial resistance, and the skin is warm and dry. A decrease in cardiac output with an increase in peripheral arterial resistance indicates a low kinetic state, which is usually seen in the later stages of septic shock. Hemodynamics with a pulmonary artery catheter is helpful in the exclusion of septic shock. Unlike hypovolemic shock, the cardiac output is mostly normal or increased and the peripheral resistance is reduced. The central venous pressure and pulmonary occlusion pressure are not. Will decrease. Electrocardiograms can show non-specific ST-T wave abnormalities and supraventricular and ventricular arrhythmias, some of which may be related to hypotension.

In the early stage of septic shock, the white blood cell count can be significantly reduced, in which polymorphonuclear leukocytes can be reduced to 20%, and the platelet count can be drastically reduced to 50000/l. However, it usually reverses quickly within 1 to 4 hours, and the total number of white blood cells and polymorphonuclear leukocytes rises significantly (polymorphonuclear leukocytes can rise to 80%, and immature white blood cells predominate).

In the early stage, respiratory alkalosis with low PCO2 and increased arterial blood pH may occur, which is also a compensation for lactic acidemia. Serum sodium bicarbonate usually decreases, while serum and blood lactic acid increase, as the shock progresses, Metabolic acidosis occurs, early respiratory failure can lead to hypoxemia, oxygen partial pressure (PO2) <70mmHg, ECG can be seen ST segment depression, T wave inversion, occasional atrial or ventricular arrhythmia, due to kidney Decreased function and creatinine clearance, blood urea nitrogen and creatinine concentrations gradually increased.

Septic shock examination

Hemodynamics with a pulmonary artery catheter is helpful in the exclusion of septic shock. Unlike hypovolemic shock, the cardiac output is mostly normal or increased and the peripheral resistance is reduced. The central venous pressure and pulmonary occlusion pressure are not. Will be reduced, ECG can show non-specific ST-T wave abnormalities and supraventricular and ventricular arrhythmia, part of the cause of this abnormality may be related to hypotension.

In the early stage of septic shock, the white blood cell count can be significantly reduced, in which polymorphonuclear leukocytes can be reduced to 20%, and the platelet count can be drastically reduced to 50000/. However, it usually reverses quickly within 1 to 4 hours, and the total number of white blood cells and polymorphonuclear leukocytes rises significantly (polymorphonuclear leukocytes can rise to 80%, and immature white blood cells predominate). Urine analysis can find urinary tracts, especially the urinary tract inserted into the catheter is the source of infection.

In the early stage, respiratory alkalosis with low PCO2 and increased arterial blood pH may occur, which is also a compensation for lactic acidemia. Serum sodium bicarbonate is usually reduced, while lactic acid in serum and blood is increased. As the shock progresses, metabolic acidosis occurs, and early respiratory failure can lead to hypoxemia, oxygen partial pressure (PO2) <70mmHg, ECG can be seen in ST segment depression, T wave inversion, occasional atrial or ventricular Arrhythmia. Blood urea nitrogen and creatinine concentrations gradually increase due to decreased renal failure and creatinine clearance.

Diagnosis of septic shock

diagnosis

Diagnosis can be made based on clinical manifestations, examinations, and the like.

Identification

Septic shock should be differentiated from hypovolemic shock, cardiogenic shock, and obstructive shock. Determination of urinary specific gravity and permeability is helpful. Hypovolemic shock responds rapidly to supplemental blood volume, typical cardiogenic shock. Often associated with myocardial infarction, obstructive shock is a complication of pulmonary artery or other major vascular occlusion due to pulmonary embolism or complications of aneurysm dissection.

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