Module 13 - Circulatory Shock Flashcards
Shock
Generalized inadequacy of blood flow throughout the body to the extent that the tissues are damaged
Can lead to every organ having no blood flow and leading to organ death ultimately
Other than organs, what else can deteriorate in shock?
Heart muscle, walls of blood vessels and other circulatory parts
Shock usually results from …
inadequate cardiac output in relation to the needs of tissue metabolism
Stages of Shock
- Compensated
- Progressive
- Irreversible
Compensated Shocvk
first stage
tissue perfusion is deficient, but not to the degree that the cardiovascular system begins to deteriorate yet
Progressive Shock
second stage
circulatory system begins to deteriorate leading to a cycle ending in death unless appropriate treatment is started
Irreversible Shock
third stage
shock has progressed to the point where all forms of therapy will be inadequate to save a person’s life
this is the point where the heart cannot pump effectively causing a decrease in CO, and this CO will continue to drop until a point of no return
3 Major Types of Shock
Hypovolemic Shock
Obstructive Shock
Distributive Shock
Hypovolemic Shock
Shock from loss of whole blood, plasma, or ECF
It comes from a lack of circulating volume which causes a lack of perfusion
ex: Burns causing plasma loss
Obstructive Shock
Inability of the heart to fill properly (cardiogenic shock including cardiac tamponade)
Obstruction to outflow from the heart occurs (PE, pneumothorax, etc)
It is a difficulty against pumping
Distributive Shock
Loss of sympathetic vasomotor tone (Neurogenic shock)
Presence of vasodilating substances in the blood (anaphylactic shock)
Presence of inflammatory mediators in the systemic circulation (septic shock)
You have enough blood and volume in the system, but so much vasodilation occurs so it is stretched thin across the body so not enough gets to the organs - anything causing massive VASODILATION can cause this if the blood is heading to the periphery
What is the most common reason for Hypovolemic Shock?
Hemorrhage (massive volume loss)
What are some causes of Hypovolemic Shock
severe dehydration
severe burns
GI ulcers
Diarrhea
Vomiting
Sweating
Excess loss of fluid by the kidneys
Adrenal Insufficiency
Hemorrhaging (#1)
Why can adrenal insufficiency cause hypovolemic shock?
Not enough ADH means increased UO causing hypovolemia (like in diabetes)
Decrease in aldosterone means the body will not hold sodium so water won’t be held either
S/S of Hypovolemic Shock
Hypotension
Collapse of neck Veins
Poor Capillary Refill time
Anxiety
Tachycardia, Increased RR, Weak Thready Pulse
Decreased Pulse Pressure
Brief Initial rise in BP
Respiratory Alkalosis Early in Shock
Orthostatic Hypotension
Decreased UO
Pale cool moist skin
Sustained low blood pressure
Metabolic Acidosis later on
What is a very early sign of hypovolemic shock and how can we tell?
Orthostatic Hypotension
A drop in blood pressure from a BASELINE that we know of at least 15 mmHg
Why is collapse of neck veins concerning in hypovolemic shock
decreased venous return to the heart
Central venous pressure will be below normal
however this is hard to assess
Why is Anxiety a symptom of hypovolemic shock
there is hyperactivity of the SNS from EP being released
This occurs due to decreased O2 in the brain for circulation
Pulse Pressure Equation
Systolic - Diastolic
Cardiac Output Equation
SV x Pulse
Why does pulse pressure decrease in hypovolemic shock
Blood volume loss causes systolic pressure to decline more rapidly than diastolic
We may not see a diastolic change
How much does pulse pressure change as it drops with hypovolemic shock
20 mmHg potentially
Why is there a brief initial rise in BP in hypovolemic shock
EP was released from the SNS response
But it will eventually drop from loss of blood
Blood vessels of the brain and coronary arteries are not affected by the generalized vasoconstriction either so it will drop
Why does Respiratory Alkalosis occur early in hypovolemic shock
hyperventilation (increased RR) from trying to fix tissue hypoxia