Core Content: Shock

This is core content - you GOTTA know it: SHOCK

There are two main ways that cell is able to generate ATP:

  1. Oxidative phosphorylation: super efficient, requires oxygen
  2. 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

  1. Arterial oxygen content (Arterial O2 sat + Hgb)
  2. 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)


Shock is about oxygen delivery, not necessarily blood pressure.

There are four major categories of shock




  • Hypovolemic --> not enough fluid. Pipes aren't filled

Shock index

HR/SBP. >0.9, helpful for the diagnosis of occult shock

Occult Causes of non-response to vasopressors

Don't just place CVL and forget about it.






John HeislerComment