What is shock?
altered tissue perfusion and anaerobic cellular metabolism
How is shock triggered
Drop in MAP
What causes MAP to change
cardiac output, total blood volume, and size of vascular bed
What is autorregulation
ability for tissue to regulate its own blood flow based on needs
What patho changes occur before shock
MAP ↓10 and ↓blood volume by 500mL
How does the body adjust to small change and what is the outcome
- SNS activated= ↑HR, CO, peripheral vasoconstriction
- perfusion to cells, tissue, and organs
What patho changes occur in Stage 1 of shock (compensatory)
MAP↓ 10-15mmHg and ↓blood volume 1000mL
What comp mechanisms are activated?
- SNS=release Epi and Norepi to stimulate α/β → vasoconstriction (nonvital) vasodilation (vital areas) → increase in CO and O2
- RAAS=VC and aldosterone release → absorb Na/H20 → maintains circ volume
- ADH=increase in renal absorption to maintain volume
- CHP ↓=fluid shifts from interstitial spaces to capillaries
What patho changes occur in Stage 2 of shock (progressive) ?
MAP↓ 20mmHg+ and ↓blood volume 2500mL
comp mechanisms are still activated but no longer work
What additional mechanism is activated to help with shock? Consequence?
- cells switch from aerobic to anaerobic metabolism=lactic acid formation=acidosis
- cells swell as Na/water moves in and K out (hyperkalemia)
- EVEN MORE FLUID AWAY FROM CAPILLARIES
- skin, skeletal muscles, kidneys, and GI no longer perfused
- Heart and Brain=anoxic
What patho changes occur in Stage 3 of shock (refractory)?
- irreversible shock due to widespread tissue anoxia
- cell death=tissue death=organ death
Can MAP be restored in Stage 3?
Yes, but cell damage is too severe and organ death causes death of body
What are the sxs of each organ?
What are the 4 classifications of shock?
Hypovolemic, cardiogenic, obstructive, and distributed
What is hypovolemic shock?
- 15-25% blood volume loss
- decrease CO
- decrease tissue perfusion