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

• Distributive --> caused by vasodilation, pipe problem
  • Fluid responsiveness:  
    • Core Content
    • Emcrit on Fluid Responsiveness
    • REBELEM on 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
• • Case report via Circulation

• 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
    • Original RUSH Article
    • Emcrit on RUSH

RUSH Part I

RUSH Part II