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Define shock
- (hypoperfusion)
- Insufficient supply of O2 and other nutrients to body cells resulting from inadequate circulation of blood.
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What are the 3 etiologies of shock?
- Inadequate volume
- Inadequate pump function
- Inadequate vessel tone
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What are the categories of shock?
- Hypovolemic shock
- Distributive shock
- Cardiogenic shock
- Obstructive shock
- Metabolic/Respiratory shock
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Define hypovolemic shock.
Shock caused by the loss of blood or fluid from the intravascular space resulting in a low blood volume. Hemorrhagic, Nonhemorrhagic.
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Define distributive shock.
Shock associated with a decrease in intravascular volume caused by massive systemic vasodilation and an increase in the capillary permeability. Septic, Neuogenic, Anaphylactic.
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Define cardiogenic shock.
Poor perfusion resulting from an ineffective pump function of the heart. MI, CHF, Depressed pump function, Abnormal rhythm, Beta blockers/calcium channel blockers.
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What is obstructive shock?
A poor perfusion state resulting from a condition that obstructs forward blood flow. Tension Pneumothorax, Pulmonic embolism, Pericardial tamponade.
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What is metaboliic or respiratory shock?
A dysfunction in the ability of O2 to diffuse into the blood, be carried by hemoglobin, off-load at the cell, or be used effectively by the cell for metabolism.
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What is hemorrhagic hypovolemic shock?
Shock from the loss of whole blood from the inrtavascular space.
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What is nonhemorrhagic hypovolemic shock?
Shock caused by loss of fluid from the intravascular space with red blood cells and hemoglobin remaining within the vessels.
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What is burn shock?
A form of nonhemorrhagic hypovolemic shock resulting from a burn injury.
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What is anaphylactic shock?
Distributive shock in which chemical mediators cause massive systemic vasodilation and permeable, leaking capillaries.
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What is septic shock?
A type of distributive shock caused by an infection that releases bacteria or toxins into the blood.
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What is neurogenic shock?
A type of distributive shock that results from massiv vasodilation. (vasogenic shock)
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What are the immediate effects of the sympathetic stimulation during shock?
- Increase in heart rate
- Increase in force of ventricular contraction (stroke volume)
- Vasoconstriction
- Stimulation of the release of epinephrine and norepinephrine
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What does alpha stimulation result in?
Vasoconstriction, which attempts to increase systematic vascular resistance and, in turn, blood pressure.
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What does the beta 1 effect stimulate?
The heart and causes an increase in the h.r. and force of contraction. Also speeds electrical impulse traveling through the conduction system of th heart, allowing for faster heart rate.
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What does beta2 stimulation result in?
Bronchial smooth muscle dilation, skeletal muscle contractility.
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What is compensatory shock?
A stage of shock in which a cascade of organ and gland stimulation and hormones increases b.p., restores arterial wall tension, and maintains a near normal b.p. and perfusion of vital organs.
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What is decompensatory shock?
A stage of shock in which the body's compensatory mechanisms are no longer able to maintain a blood pressure and perfusion of the vital organs.
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What is irreversible shock?
A stage of shock in which interventions cannot prevent the advance of shock to death.
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What are the signs of poor perfusion?
- Altered mental status
- Pale, cool, clammy skin
- Delayed capillary refill
- Decreased urine output
- Weak or absent peripheral pulses
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What does vital sign assessment include?
- Blood pressure (systolic & diastolic)
- Heart rate
- Pulse character
- Respiratory rate and tidal volume
- Skin color, temp., and condition
- Pulse oximeter reading
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What is the lower limit of normal for blood pressure for children less than 10?
A systolic blood pressure of 70 mmHg pluse two times the age in years is the lower limit. A systolic b.p. of less than the lower limit would be considered hypotensive.
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