Shock Flashcards
(20 cards)
What is shock?
What can it lead to?
A syndrome of decreased tissue perfusion and impaired cellular metabolism, causing an imbalance between oxygen/nutrient supply and demand
- leads to cellular hypoperfusion, where cells can’t get enough O₂ and nutrients to survive
↓ blood and O₂ to tissue + cells → tissue + cells stop working properly
What are the different categories/classifications of shock?
- Cardiogenic
- Hypovolemic
- Distributive
- Anaphylactic shock
- Septic Shock
cause, initial symptoms, and management vary, but response is similar
When does cardiogenic shock occur?
there is either systolic or diastolic dysfunction of the heart’s pumping action results in reduced cardiac output
heart can’t pump blood well enough → low blood flow to the body
essentially something is going wrong with the heart’s pumping action (could be MI, dysrhythmia, etc.) → ↓ CO → ↓ tissue perfusion → cells/tissues don’t work properly (impaired celluar metabolism)
What are the clinical manifestations of cardiogenic shock?
similar to acute heart failure:
- tachycardia (compensate for ↓ CO)
- tachypnea (bc ↓ CO, need more O₂)
- hypotension
- ↓ pulse pressure
- ↓ CO
- ↓ MAP (low tissue perfusion)
What is pulse pressure?
What is the normal range?
provides information about the elasticity and
health of the arteries
normal: 40-60 mmHg
systolic BP - diastolic BP = pulse pressure
ex: 120/80, 120 - 80 = 40, pulse pressure = 40
What pulse pressure would indicate shock?
- narrow/low pulse pressure
- lack of ability to push blood forward (heart is unable to pump blood forward)
lower than 40 mmHg
When does hypovolemic shock occur?
after a loss of intravascular fluid volume
essentially, not enough fluid in the intravascular space which results in ↓ in fluid volume → ↓ venous return (↓ blood/fluid getting to heart) → ↓ CO → ↓ tissue perfusion (↓ O₂ delivery → altered cellular metabolism)
What can cause hypovolemic shock?
- Hemorrhage
- Gastrointestinal (GI) loss
- Fistula drainage
- Diabetes insipidus
- Diuresis
when fluid is lost
What can hypovolemic shock lead to?
- person can lose up to 750mL of blood volume (15%)
- if more is lost (15-30%), this can lead to SNS mediated response:
- ↑ HR
- ↑ CO
- ↑ RR and depth
trying to ↑ CO and O₂
What are clinical manifestations of hypovolemic shock?
- anxiety
- ↓ urine output
need continuous labs (labs: hgb, hct, blood gas, urine)
When does distributive shock occur?
aka neurogenic or spinal shock
there is a spinal cord injury, a hemodynamic phenomenon can occur shortly after
injury to spinal cord or brain
essentially bc of the spinal cord injury → ↓ SNS nerve impulses (no compensatory mechanisms) → pooling of blood → blood not moving to heart → blood not moving out of heart → ↓ CO → ↓ tissue perfusion (↓ O₂ delivery → altered cellular metabolism)
What can cause distributive shock?
- injury to brain or spinal cord
- spinal anesthesia (blocks impulses to SNS)
- depression of vasomotor center (opioids/benzos)
What are clinical manifestations of distributive shock?
- hypotension (massive vasodilation)
- bradycardia (no SNS nerve impulse)
- can’t regulate body temperature
- temp starts warm
- later, body becomes the temp of external environment
as a nurse, be aware of the room temperature
bradycardia is main difference bc the SNS is blocked and there is no compensatory mechanism (tachycardia) for ↓ CO
When does anaphylactic shock occur?
acute, life threatening allergic reaction
initiates the immune and circulatory response
will cause massive vasodilation → release of vasoactive mediators (histamines) → ↑ capillary permeability → fluid leaks into interstitial tissues → edema → ↓ blood volume → ↓ venous return → ↓ CO → ↓ tissue perfusion (↓ O₂ delivery → altered cellular metabolism)
What can anaphylactic shock lead to?
- respiratory distress (due to edema or bronchospasm)
- patient feels like their throat is closing up
- not enough O₂ in the body
- circulatory failure (due to massive vasodilation)
there’s going to be the immune response, then circulatory response
What are clinical manifestations of anaphylactic shock?
- dizziness (↓ O₂)
- chest pain (↓ O₂ to coronary arteries)
- swelling of lips and tongue (immune system reaction)
- wheezing (immune system reaction)
- stridor (indicates obstruction of air)
- skin changes (red, itchy, etc.)
think about severe allergic reactions
When does septic shock occur?
response to an infection in the blood
triggers immune or inflammatory response (exaggerated)
platelet activating factors are released → forms microscopic clots → obstruction in capillaries → vasodilation → ↑ capillary permeability → altered blood flow → ↓ CO → ↓ tissue perfusion (↓ O₂ delivery → altered cellular metabolism)
What can septic shock lead to?
- cardiovascular dysfuntion
- respiratory failure
- initially hyperventilates → respiratory alkalosis
- later, compensatory failure gives up and breathes slower → respiratory acidosis
will need to be intubated and mechanically ventilated
What are clinical manifestations of septic shock?
- altered neuro status (↓ CO)
- ↓ urine output (↓ CO, ↓ blood flow to kidneys)
- GI dysfunction (↓ CO)
Why is there vasodilation and not vasoconstriction with septic shock, distributive shock, and anaphylactic shock?
- Septic: body releases chemicals to fight infection which cause inflammation and dilation
- Distributive: loss of sympathetic impulse, so the vessels can’t constrict
- Anaphylactic: releases histamine, which causes blood vessels to open up
issue isn’t the heart/fluid, it’s bc the vessels are relaxed and wide
unable to push blood around (vasoconstriction) bc the vessels are too loose (vasodilation) → blood pools in the body → ↓ blood pressure and ↓ tissue perfusion
