Shock

Question 1

Major physiologic determinants of tissue perfusion (BP)

Answer 1

CO x SVR

• CO = HR x SV
• SV is determined by preload, afterload, contractility

Question 2

Stages of shock:

Reflex compensatory mechanisms (sympathetics) are activated and tissue perfusion is maintained

Answer 2

Compensated stage

Question 3

Stages of shock:

Tissue hypoperfusion and onset of worsening circulatory and metabolic derangement

Hypotension and lactic acidosis

Answer 3

Decompensated stage

Question 4

Stages of shock:

Organ and tissue injury is so severe that survival not possible even if hemodynamic defects are restored

Answer 4

Irreversible stage

Question 5

Type of shock?

Decreased CO
Increased SVR
Increased PCWP

Answer 5

Cardiogenic shock (bad pump)

• Heart is unable to contract and maintain CO
• Can be caused by cardiomyopathy, arrhythmia, mechanical defects

Question 6

Explain the following variables in cardiogenic shock.

Decreased CO
Increased SVR
Increased PCWP

Answer 6

• Decreased CO due to bad pump
• Increased SVR due to attempt to maintain perfusion (vasoconstriction)
• Increased PCWP due to backup of volume into lungs

Question 7

Type of shock?

Decreased CO
Increased SVR
Decreased PCWP

Answer 7

Hypovolemic shock

*Typically due to hemorrhage or dehydration

Question 8

Explain the following variables in cardiogenic shock.

Decreased CO
Increased SVR
Decreased PCWP

Answer 8

• Decreased CO due to lack of volume
• Increased SVR due to attempt to maintain perfusion (vasoconstriction)

Decreased PCWP due to lack of volume

Question 9

Type of shock?

Increased CO
Decreased SVR
Decreased PCWP

Answer 9

Septic and anaphylactic shock (distributive)

*Due to infection or allergic rxn

Question 10

Explain the following variables in septic and anaphylactic (distributive) shock.

Increased CO
Decreased SVR
Decreased PCWP

Answer 10

• 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

Question 11

Type of shock?

Decreased CO
Decreased SVR
Decreased PCWP

Answer 11

Neurogenic shock (distributive)

• loss of autonomic function
• due to spinal cord injury

Question 12

Explain the following variables in neurogenic (distributive) shock.

Decreased CO
Decreased SVR
Decreased PCWP

Answer 12

Loss of autonomic function

cannot maintain HR or SVR

Question 13

Type of shock?

Decreased CO
Increased SVR
Variable PCWP

Answer 13

Obstructive shock

• Heart unable to pump due to mechanical obstruction
• Can be due to PE, tension pneumothorax, tamponade

Question 14

Explain the following variables in obstructive shock.

Decreased CO
Increased SVR
Variable PCWP

Answer 14

Decreased CO due to heart having a mechanical obstruction

-Increased SVR due to attempt to maintain perfusion (vasoconstriction)