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Define Shock
- the abnormal physiologic state that is the first phase of the body's alarm reaction to an insult or injury.
- - progresses to multiple system organ failure
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When does shock occur?
CV system fails to perfuse tissues adequately
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What happens if shock is left untreated?
progressive circulatory collapse occurs, compensatory mechanisms unable to adjust, death results.
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What are the three classifications of shock?
- 1. Hypovolemic shock: decreased intravascular volume
- 2. Cardiogenic shock: pump failure
- 3. Distributive shock "vasogenic shock" : includes neurogenic, anaphylactic (hypersensitivity), and septic (infection) - alterations in smooth muscle tone.
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Define hypovolemic shock.
occurs when there is a 15-20% loss of the blood volume.
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What is the most common cause of hypovolemic shock?
- excessive blood loss through trauma of major blood vessel or organ- spleen, liver, kidney
- - hemorrhage
- -severe burn
- -overuse of diuretics
- -third spacing (ascites)
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The severity of hypovolemic shock relies on ...
amount and rate of blood loss.
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When is hypovolemic shock irreversible?
If volume loss is not replaced quickly and the aortic pressure is low for longer than 60 minutes.
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What are common clinical manifestations of hypovolemic shock?
- Low: CO, CVP, PAP, BP, UO, pulse, pH (acidosis), O2 (hypoxemia)
- High: SVR, HR, RR,
- -Cold, clammy skin, Confusion, Restless, Pallor
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In hypovolemic shock three main compensatory mechanisms are activated:
- 1. Vasoconstrictor
- 2. Shift fluid from interstitial to intravascular compartment
- 3. Increased pumping efficiency of the heart
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What is the treatment for hypovolemic shock?
- 1. Treat the cause
- 2. Volume replacement
- 3. O2
- 4. Monitor: EKG, Hemodynamic status, UO
- 5. Vasopressors (not effective until volume is replaced)
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Define Cardiogenic shock.
heart fails to maintain an adequate CO to meet the body's metabolic needs.
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What is the most common cause of Cardiogenic shock?
- Acute MI: most common cause
- - heart failure, post open heart surgery, cardiomyopathy, valvular heart disease, arrhythmias, mechanical defects-VSD, myocardial infections, drug toxicity
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Clinical manifestations of Cardiogenic shock.
- impaired thinking
- Low: BP, hypoxemia, pH (acidosis), SOB, UO to oliguria, CO
- High: HR, preload, pulmonary edema
- - Pallor to cyanosis
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What is the treatment for cardiogenic shock?
1. Regulation of fluid volume: frank-starling mechanism without pulmonary congestion done through hemodynamic monitoring
2. Promote pumping ability of heart (CO): inotropic drugs like dopamine and dobutamine, control arrhythmias, afterload reduction through NTG, and Nitropusside IABP
3. Increase blood flow: regulation of bp via fluid replacement or dopamine
4. Neutralize the effects of tissue hypoxia through bicarb
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Define distributive shock
normal pump, normal volume but intravascular volume is mal-distributed within circulatory system.
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When does distributive shock occur?
when there is a loss of blood vessel tone
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Which types of shock fall under the classification of distributive shock?
- 1. Neurogenic Shock
- 2. Anaphylactic Shock
- 3. Septic Shock
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Define neurogenic shock
results from an imbalance between parasympathetic and sympathetic NS - due to decreased sympathetic control of blood vessel tone.
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What causes neurogenic shock?
- -brain injury
- -death
- -hypoxia
- -hypoglycemia
- -SCI
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Define anaphylactic shock
"distributive shock" - result of widespread hypersensitivity reaction
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Define septic shock
- type of distributive shock
- - develops because of body's immune and inflammatory responses to endotoxins released when gram negative bacteria is destroyed
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Which type of distributive shock is most common?
Septic Shock
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Septic shock is marked by altered _______, decreased _____ ______, and the loss of ______ _______.
- altered hemodynamics
- decreased tissue perfusion
- loss of cellular energy
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the over-response in severe septic shock disrupts homeostasis through ....
- an uncontrolled cascade:
- -inflammation
- -coagulation
- -impaired fibrinolysis
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The increasing severity and mortality of sepsis is illustrated by a contiuum of events:
- -SIRS
- -Severe sepsis
- -Septic Shock
- -Multiple organ dysfunction (MOD), which often leads to death
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Manifestations of SIRS includes the presence of more than one of the following:
- Temp >100.4 or <96.8
- HR > 90 bpm
- RR > 20 or hyperventilation PaCO2<32
- WBC >12,000 or < 4,000
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Who is at risk of developing severe sepsis?
- -age
- -malnutrition
- -debilitation
- -chronic health issue
- -bladder infection
- -defects in skin integrity
- -untreated GI
- -Immunosuppression
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What are some common complications of shock?
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What are the three stages of clinical manifestations in septic shock?
1. Hyperdynamic: confused, flushed & warm skin, bounding pulse, increased HR & CO, normal BP, decreased SVR
2. Normodynamic: short hard to recognize
3. Hypodynamic: cold and clammy skin, hypotension, weak thready pulse, hypoxia, acidosis, decreased UO, high PAP and CVP pressure, respiratory failure
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What is the treatment of septic shock?
antimicrobial, remove infection source, fluid, activated protein C
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