Shock Flashcards

1
Q

What is shock?

A

Clinical state of cardiovascular collapse characterized by the inadequate perfusion of the cells and tissues resulting in hypotension and cellular hypoxia and if uncompensated, may lead to impaired cellular metabolism and death.

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2
Q

What are the stages of shock?

A
  1. Initial stage
    - tissues are under perfused, decreased oxygen, increased anaerobic metabolism, lactic acid is building
  2. Compensatory stage
    - reversible
    - attempting to compensate for the decrease tissue perfusion
    - neuroendocrine, hematology, CVS, renal
  3. Progressive stage
    - failing compensatory mechanisms
    - profound vasoconstriction
    - lactic acid production is high - metabolic acidosis
  4. Irreversible or refractory stage
    - cellular necrosis
    - multiple organ dysfunction syndrome may occur
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3
Q

What are the types of shock?

A
  1. Hypovolemic shock
    - blood volume problem
  2. Cardiogenic shock
    - blood pump problem
  3. Distributive shock
    - blood vessel problem
    - septic, anaphylatic and neurogenic
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4
Q

What is hypovolemic shock?

A

Medical or surgical condition in which rapid blood or fluid loss results in multiple organ failure due to inadequate circulating volume and subsequent inadequate perfusion

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5
Q

What are the causes of hypovolemic shock?

A
  1. Blood loss
    - traumatic injury (blunt trauma)
    - vascular disorders (e.g. aneurysms, dissections, arteriovenous malformations)
    - GI disorders
    - pregnancy-related disorders
  2. Fluid loss
    - refractory gastroenteritis
    - extensive burns
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6
Q

What is the pathophysiology of hypovolemic shock?

A

low venous return > low preload > low CO > hypotension > perfusion failure & tissue hypoxia > organ dysfunction > multiorgan failure

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7
Q

Compensatory mechanism mostly occurs during what type of shock?

A

Hypovolemic shock

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8
Q

What are the four components that make up the compensatory mechanism?

A
  1. Hematology system
  2. Cardiovascular system
  3. Renal system
  4. Neuroendocrine system
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9
Q

Describe the hematology system of compensatory mechanism

A
  1. Activates the coagulation system and contracting bleeding vessels (thromboxane A2)
  2. Immature clot that is not stable will form on the bleeding source
  3. Fibrin deposition occur due to exposed collagen (due to damaged vessels) to stabilize the immature clot and stop from bleeding
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10
Q

Describe the cardiovascular system in compensatory mechanism

A
  1. Increased release of norepinephrine & decreased baseline vagal tone to increase heart rate, myocardial contractility & constrict peripheral blood vessels
  2. This will increase the volume in the blood vessels
  3. Redistribution of blood to vital organs like brain, heart & kidney (away from skin, muscle & GI tract)
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11
Q

Describe the renal system in compensatory mechanism

A
  1. Stimulating an increase in renin-angiotensin-aldosterone system due to reduced volume in kidney
  2. Angiotensin II - to vasoconstrict arteriolar smooth muscle and aldosterone secretion by adrenal cortex
  3. Aldosterone - responsible for active sodium reabsorption and water conservation (to reduce water secretion in kidney and maintain/increase volume in vessels)
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12
Q

Describe the neuroendocrine system in compensatory mechanism

A
  1. Increase in circulating ADH by posterior pituitary gland
  2. In response to decrease in BP & decrease in sodium concentration
  3. ADH - will increase water reabsorption of water and salt by distal tubule, collecting duct and loop of Henle
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13
Q

What is the principle management of hypovolemic shock

A

To restore circulating volume, tissue perfusion and correct cause

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14
Q

What is the management of hypovolemic shock in emergency department care

A
  1. Maximize oxygen delivery
  2. Control further blood loss
  3. Fluid resuscitation
  4. Medication e.g. Somatostatin (have vasoconstrictive properties & can reduce blood flow to portal systems)
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15
Q

What is the definition of cardiogenic shock

A

Decreased CO due to cardiac dysfunction and evidence of tissue hypoxia in the presence of adequate intravascular volume (normal volume)

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16
Q

What are the causes of cardiogenic shock

A
  • systolic dysfunction - ischemia, severe myocarditis
  • diastolic dysfunction - ventricular hypertrophy, restrictive cardiomyopathy
  • valvular dysfunction - mitral stenosis, endocarditis
  • cardiac arrythmias - ventricular arrythmias
17
Q

What are the principles of management for cardiogenic shock

A
  1. Treat reversible causes
  2. Protect ischemic myocardium
  3. Improve tissue perfusion
18
Q

What are the managements of cardiogenic shock

A
  1. Fluid resuscitation (to correct hypotension unless pulmonary edema is present)
  2. Pharmacologic therapy (to maintain BP and CO)
  3. Admission to intensive care setting (ICU)
  4. Early and definitive restoration of coronary blood flow
  5. Correction of electrolyte and acid-base abnormalities
19
Q

What is distributive shock?

A
  • results from excessive vasodilation and maldistribution of blood flow
  • the heart & blood volume are normal but the vessels have problem (blood not reaching the tissues)
20
Q

What us septic shock

A
  • A type of distributive shock due to infection
  • results from vasodilatation and peripheral pooling of blood as part of a systemic immune reaction to infection
  • most common sites of infection are chest, abdomen, and genitourinary tract
21
Q

Pathophysiology of sepsis

A
  1. Early phase : Hyperdynamic (warm shock)
    - massive vasodilation
    - skin will become warm
    - tissue hypoxia
  2. Late phase : Hypodynamic (cold shock)
    - vasoconstriction
    - skin becomes pale & cold
    - will cause tissue ischemia, necrosis and death
22
Q

Clinical presentation of early state and late state sepsis

A
  1. Early state
    - pink, warm, flushed skin
    - increased heart rate
    - tachypnea
    - massive vasodilation
    - increased CO
  2. Late state
    - vasoconstriction
    - skin is pale and cold
    - tachycardia
    - decrease BP
    - change in mental status
    - decrease CO and urine output
23
Q

What is anaphylatic shock

A

A type of distributive shock that is due to allergic reaction to an antigen. It is LIFE THREATENING.

24
Q

What is neurogenic shock

A
  • A type of distributive shock that results from the loss of sympathetic tone.
  • It causes massive vasodilatation, reduce venous return to heart, and reduce CO.
  • Most common cause is spinal cord injury above T6 (location of sympathetic tone)
25
Q

Clinical presentation of neurogenic shock

A
  • hypotension
  • bradycardia (bcs sympathetic loss)
  • hypothermia
  • warm, dry skin
  • reduce CO
  • flaccid paralysis below level of the spinal lesion (bilateral lower limb paralysis)