Shock Flashcards
SHOCK
inadequate CO
failure of the circulatory system to supply the peripheral tissues with adequate BF
late sign of failure of compensatory mechanisms
hypotension (abnormally low blood pressure)
Types of Shock
Distributive
Obstructive
Cardiogenic
Hypovolemic
Distributive shock
-abnormal distribution of blood flow
sepsis, or anaphylaxis from the release of inflammatory mediators
Obstructive shock
-physical obstruction of the great vessels or the heart itself
(pulmonary embolism, cardiac tamponade, tension pneumothorax)
Cardiogenic shock
-suddenly! the heart can’t pump enough blood to meet the body’s needs
(acute myocardial infarction, heart disease, cardiac arrhythmias)
Hypovolemic shock
-decreased blood volume
loss of blood (hemorrahge
loss of plasma (burn)
ECF (GI losses)
Distributive shock causes
- loss of vascular tone
- enlargement of vascular compartment
- displacement of vascular volume away from central circulation
- more blood in periphery, less in central circulation
- loss of SNS vasomotor drive (neurogenic shock)
- vasodilators in blood (anaphylactic shock)
- presence of inflammatory mediators (septic shock)
3 types of distributive shocks
neurogenic - loss of SNS vasomotor drive
anaphylactic - vasodilators in blood
septic - presence of inflammatory mediators
Neurogenic shock
DISTRIBUTIVE SHOCK
-loss of neural influence on vasculature => lose vasomotor tone
(decrease SVR) and MABP falls
rare and transitory
Anaphylactic shock
DISTRIBUTIVE SHOCK
- immune mediated reaction
- vasodilators (histamine)
- decrease SVR, MABP falls
histamine
anaphylactic shock - distributive shock
decrease SVR, MABP falls
dilates arterioles and venules
increases permeability of capillaries and venules
Causes of neurogenic shock
DISTRIBUTIVE SHOCK
- brain injury
- drugs (general anesthesia)
- insulin reaction (lack of glucose)
- hypoxia
- spinal cord injury
Causes of anaphylactic shock
DISTRIBUTIVE SHOCK
-allergic reaction: drugs, foods, stings, latex
How to alleviate anaphylactic shock?
DISTRIBUTIVE SHOCK
epinephrine - open airways (vasoconstriction to increase SVR)
cold - to delay absorption and spread
What is the most common form of shock among patients in the ICU?
septic shock
Septic shock definition
sepsis (organ injury or damage in response to infection) leads to dangerously low blood pressure and abnormalities in cellular metabolism
What form of shock is hemorrhage and how?
hypovolemic shock
-loss of BV
Baroreceptors respond to ___
stretch
high MABP, high BR => inc. psns to compensate
low MABP, low BR => increase sns to compenaste
if low arterial baroreceptor firing, what to do to compensate?
increase sns
increase adh
In response to hemorraghe, what does the SNS effect?
arterioles increase SVR veins: decrease compliance, inc VR heart liver hypothalamus, posterior pituitary for ADH
In response to hemorrhage, what does the sns do to the veins?
alpha 1 receptor
decreases compliance
increases venous return
inc. ventricular filling
inc. sv toward normal
In response to hemorrhage, what does the sns do to the aterioles?
increase svr,
inc. water reabsorption
inc. lactic acid production
CO and MABP is maintained if less than ____ %of BV is lost.
10%
