SHOCK

• Is a syndrome characterized by:
• decreased tissue perfusion and impaired cellular metabolism which =>
• imbalance b/w the supply of and demand for O_{2 and nutrients => hypoperfusion}

LOW BLOOD FLOW (cardiogenic and hypovolemic)

MALDISTRIBUTION OF BLOOD FLOW (septic, anaphylactic, and neurogenic shock)

• systolic dysfunction inability of the heart to pump blood forward
• ie. MI, cardiomyopathy
• diastolic dysfunction inability of the heart to fil during diastole
• ie. pericardial tamponade
• dysrhythmias (bradydysrhythmias, tachydysrhythmias)
• structural factors valvular abnormality (stenosis or regurgitation), ventricular septal rupture, tension pneumothorax

• absolute hypovolemia
• external loss of whole blood (hemorrhage from trauma, surgery, gi bleeding

loss of other body fluids (vomiting , diarrhea, excessive diuresis, diabetes isnipidus, DM)

• Relative hypovolemia
• pooling of blood or fluids (bowel obstruction)
• fluid shifts (burn injuries, ascities)
• internal bleeding (fx of long bones, ruptured spleen, hemothorax, severe pancreatitis)
• massive vasodilation (sepsis)

• hemodynamic consequence of injury and/or disease to the spinal cord at or above T5
• spinal anesthesia
• vasomotor center depression (severe pain, drugs, hypoglycemia, injury)

contrast media, blood/blood products, drugs, insect bites, anesthetic agents, food/food additives, vaccines, environmental agents, latex

infection (urinary tract, respiratory tract, invasive procedure, indwelling lines and catheters)

• At risk:
• older adults, pts w chronic diseases (/dm, chronic kidney disease, HF) immunosuppressive therapy or who are malnourished or debilitated

Gram-negative bacteria most common; gram positive bacteria, viruses, fungi, and patasites

Mediator excess: cytokines (tumor necrosis factor, interleukins), oxygen free radicalss

widespread endothelial injury and dysfunction

vasodilation and increased capillary permeability

tissue edema

neutrophil entrampment in microcirculation

• Target organs
• cardiovascular dysfunction
• lung dysfunction
• GI dysfunction
• liver dysfunction
• CNS dysfunction
• Renal dysfunction
• Skin dysfunction