Shock Flashcards
Major physiologic determinants of tissue perfusion (BP)
CO x SVR
- CO = HR x SV
- SV is determined by preload, afterload, contractility
Stages of shock:
Reflex compensatory mechanisms (sympathetics) are activated and tissue perfusion is maintained
Compensated stage
Stages of shock:
Tissue hypoperfusion and onset of worsening circulatory and metabolic derangement
Hypotension and lactic acidosis
Decompensated stage
Stages of shock:
Organ and tissue injury is so severe that survival not possible even if hemodynamic defects are restored
Irreversible stage
Type of shock?
Decreased CO
Increased SVR
Increased PCWP
Cardiogenic shock (bad pump)
- Heart is unable to contract and maintain CO
- Can be caused by cardiomyopathy, arrhythmia, mechanical defects
Explain the following variables in cardiogenic shock.
Decreased CO
Increased SVR
Increased PCWP
- Decreased CO due to bad pump
- Increased SVR due to attempt to maintain perfusion (vasoconstriction)
- Increased PCWP due to backup of volume into lungs
Type of shock?
Decreased CO
Increased SVR
Decreased PCWP
Hypovolemic shock
*Typically due to hemorrhage or dehydration
Explain the following variables in cardiogenic shock.
Decreased CO
Increased SVR
Decreased PCWP
- Decreased CO due to lack of volume
- Increased SVR due to attempt to maintain perfusion (vasoconstriction)
Decreased PCWP due to lack of volume
Type of shock?
Increased CO
Decreased SVR
Decreased PCWP
Septic and anaphylactic shock (distributive)
*Due to infection or allergic rxn
Explain the following variables in septic and anaphylactic (distributive) shock.
Increased CO
Decreased SVR
Decreased PCWP
- Increased CO (tachycardia) to try and maintain perfusion
- Decreased SVR due to mass vasodilation (response to allergy or toxin)
- Decreased PCWP due to volume distribution out of vasculature
Type of shock?
Decreased CO
Decreased SVR
Decreased PCWP
Neurogenic shock (distributive)
- loss of autonomic function
- due to spinal cord injury
Explain the following variables in neurogenic (distributive) shock.
Decreased CO
Decreased SVR
Decreased PCWP
Loss of autonomic function
cannot maintain HR or SVR
Type of shock?
Decreased CO
Increased SVR
Variable PCWP
Obstructive shock
- Heart unable to pump due to mechanical obstruction
- Can be due to PE, tension pneumothorax, tamponade
Explain the following variables in obstructive shock.
Decreased CO
Increased SVR
Variable PCWP
Decreased CO due to heart having a mechanical obstruction
-Increased SVR due to attempt to maintain perfusion (vasoconstriction)
