Core Content: Shock
This is core content - you GOTTA know it: SHOCK
There are two main ways that cell is able to generate ATP:
- Oxidative phosphorylation: super efficient, requires oxygen
- Substrate level phosphorylation: anaerobic; super inefficient, produces lactate --> only thing to do when you have local or systemic cellular hypoxia
There are two primary determinants of oxygen delivery (DO2): Cardiac Output, Arterial O2 Content

- Arterial oxygen content (Arterial O2 sat + Hgb)
- Cardiac output (HR x SV)
- stroke volume determined by:
- preload (how much blood is in the ventricle at the end of diastole)
- afterload (or the force the heart has to pump against)
- inotropy (how hard the heart is squeezing)
- stroke volume determined by:
Shock is about oxygen delivery, not necessarily blood pressure.
There are four major categories of shock
- Distributive --> caused by vasodilation, pipe problem
- Fluid responsiveness:
- Cardiogenic --> bad heart. problem with the pump
- Obstructive --> most of the time issues with the RV; back-up of flow due to blockage in the pipes
- Hypovolemic --> not enough fluid. Pipes aren't filled
Shock index
HR/SBP. >0.9, helpful for the diagnosis of occult shock https://www.ncbi.nlm.nih.gov/pubmed/23599863/
Occult Causes of non-response to vasopressors
Don't just place CVL and forget about it. http://rebelem.com/occult-causes-of-non-response-to-vasopressors/
- Valuable tools:
- POCUS
- RUSH exam --> Rapid ultrasound in shock. Checking the pump, tank and pipes for causes of hypotension
RUSH Part I
RUSH Part II