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Definition of Shock

Jonathan Napper

"Shock is the clinical expression of circulatory failure that results in inadequate cellular oxygen utilization." - Jean-Louis Vincent, M.D., Ph.D., and Daniel De Backer, M.D., Ph.D.

Subtypes (further outlined below):

  • Distributive (septic, anaphylactic, neurogenic, and rarely adrenal)
  • Cardiogenic (cardiomyopathies, arrhythmias, severe valvular diseases)
  • Hypovolemic (bleeding, volume deplete states)
  • Obstructive (PE, tension PTX, cardiac tamponade, restrictive cardiomyopathies, constrictive pericarditis)

Signs:

  • Systolic BP < 90 mmHg or MAP < 70 mmHg, with associated tachycardia AND
  • Clinical signs of tissue hypoperfusion.
    • Cutaneous (cold, clammy skin w/ vasoconstriction and cyanosis, evident in low-flow states)
    • Renal (UOP of <0.5ml/kg of body weight/hr)
    • Neurologic (AMS typically with obtundation, disorientation confusion).
  • Hyperlactatemia (indicates abnormal cellular oxygen metabolism)