Shock Flashcards
define shock
state in which decreased cardiac output or effective circulating blood volume leads to hypoxia and impaired tissue function
Types of shock
Hypovolemic
Cardiogenic
Distributive
Obstructive
What are the phases of shock and describe them
Compensated “Pre-shock”- reflex compensatory mechanisms are activated so perfusion is maintained
“Progressive” Decompensated shock- tissue hypoperfusion and onset of worsening circulatory and metabolic imbalances (hypoxia leads to lactic acidosis)
Irreversible Shock- cellular and tissue injury to the point of impossible survival (lysosomal leakage and necrosis)
Oxygen delivery equation and its components
CaO2= [Hb x 1.39 x SaO2) + PaO2 x 0.03)]
What most commonly causes hypovolemic shock and examples of hypovolemic shock
decreased venous return
- hemorrhagic shock
- traumatic shock
- surgical shock
- burn shock
Describe the sequelae of hypovolemic shock
Decreased intravascular volume leads to:
- decreased LVEDP
- Generalized vasoconstriction
- Sodium/water retention leading to the expansion of blood volume
- increased extraction of O2 from the blood
describe cardiogenic shock
inappropriately low cardiac output, despite normal or high central venous (RA pressure)
What causes cardiogenic shock and what are the consequences
- Decreased contractility leads to infarction
- Increased diastolic stiffness leads to ventricular hypertrophy and restrictive cardiomyopathy
- Increased afterload
- abnormal rate/ rhythm: V tach
- valve dysfunction leads to mitral regurg and rupture of IV shunt
what is distributive shock and what are examples
condition of reduced oxygen delivery where the primary physiologic disturbances is a reduction in SVR
septic shock
adrenal crisis
endocrine shock
neurogenic shock
anaphylaxis
pancreatitis
liver failure
burns
consequences of distributive shock
- compensatory increase in CO
- central venous pressure and pulmonary capillary wedge pressure are decreased
most common sites of septic infection
respiratory tract
GU
abdomen
device implants
wound/ soft tissue infections
explain the pathogenesis of septic shock
Morphology of shock in the adrenal gland
cortical cell lipid depletion
hemorrhagic necrosis leading to Waterhouse Friedrichsen syndrome
Morphology of shock in the lungs
Gross: congested/ firm tissue with frothy fluid exuding from the cut surface
Micro: diffuse alveolar damage with alveolar hyaline membranes
Morphology of shock in the kidney
acute tubular necrosis
Morphology of shock in GI
gastric mucosal erosions and superficial ischemic necrosis in the intestines with diffuse GI hemorrhage
Morphology of shock in the liver
hepatomegaly with a mottled cut surface that reflects marked centrilobular congestion and necrosis of the blood
Morphology of shock in the pancreas
impaired splanchnic circulation with ischemic damage to the exocrine pancreas
acute pancreatitis due to activated pancreatic enzymes
Morphology of shock in the brain
watershed infarcts if severe
