Chapter 6 Shock

Question 1

4 Types of Shock

Answer 1

1. Hypovolemic - reduction in circulating intravascular volume
2. Distributive - impairment of mechanisms regulating vascular tone, inadequate effective circulating volume
3. Cardiogenic - inability of heart to propel blood through circulation
4. Hypoxic - adequate tissue perfusion but inadequate arterial oxygen content or cellular oxygen utilization

Question 2

Two types of cardiogenic shock

Answer 2

Diastolic failure
Systolic failure

Question 3

What are examples of systolic failure causing cardiogenic shock?

Answer 3

Myocardial dysfunction (CHF, DCM)
Severe arrythmia
Mechanical defects (valvular defect, stenosis/insufficiency)
Drugs

Interferes with hearts ability to pump blood

Question 4

What are examples of diastolic failure causing cardiogenic shock?

Answer 4

HCM
Cardiac tamponade
Pericardial fibrosis
Tension pneumothorax

Interferes with hearts ability to fill

Question 5

What causes hypovolemic shock?

Answer 5

Reduction in circulating intravascular volume
- Hemorrhage
- Loss of other body fluids

Question 6

What are examples of distributive shock?

Answer 6

Sepsis, SIRS, anaphylaxis, drugs, neurogenic shock

Question 7

What is neurogenic shock?

Answer 7

Disruption in autonomic nervous system causes loss of sympathetic tone (vasodilation, hypotension, decreased tissue perfusion)
- spinal cord injury, TBI, seizures, spinal tumors

Question 8

What are examples of causes of hypoxic shock?

Answer 8

Hypoxemia
Anemia
Methemoglobinemia
Carbon monoxide posoning
Metabolic or cytopathic (sepsis/toxins)

Question 9

Anaphylactic shock decreases central venous pressure TRUE or FALSE

Answer 9

True

Question 10

What increases central venous pressure?

Answer 10

Cardiogenic shock
Right CHF
Pleural space disease
Pericardial effusion
Fluid overload
Increased intrathoracic pressure

Question 11

What decreases central venous pressure?

Answer 11

Shock
Hypovolemia
Vasodilation

Question 12

How do you measure cardiac output?

Answer 12

CO = HR x SV

Question 13

How do you measure stroke volume?

Answer 13

SV = preload, afterload, and contractility

Question 14

What three main categories of abnormalities can result in reduction of arterial oxygen content?

Answer 14

• Anemia
• Altered hemoglobin function
• Hypoxemia

Question 15

What is VO2

Answer 15

VO2 = Oxygen uptake
Measures rate at which oxygem leaves Hgb in systemic capillaries and reaches tissues

Question 16

What are 5 possible defects that can affect oxygen uptake (VO2)?

Answer 16

1. Diffusional shunting
2. Diffusional resistance
3. Arteriovenous shunting
4. Perfusion/metabolism mismatch
5. Cytopathic hypoxia (mitochondrial dysfunction)

Question 17

What causes the oxygen-hemoglobin dissociation curve to shift to the LEFT?

Answer 17

• Decrease in temperature
• Decrease in PCO2
• Decrease in DPG
• Increase in pH

Question 18

What causes the oxygen-hemoglobin dissociation curve to shift to the RIGHT?

Answer 18

• Increase in temperature
• Increase in PCO2
• Increase in DPG
• Decrease in pH

Question 19

What is normal central venous pressure?

Answer 19

0-5 cm H2O
CVP is closely correlated with right atrial pressure and therefore cardiac preload

Hypovolemic shock or vasodilation - CVP typically decreased (<0cm H2O).

Cardiogenic shock - CVP typically increased (>10cm H2O).

Question 20

How is central venous pressure monitored?

Answer 20

Catheter tip placed in cranial or caudal vena cava or at junction between vena cava and right atrium
Hydrostatic pressure measured throught he catheter

Question 21

What are two types of lactic acidosis?

Answer 21

Type A: inadequate oxygen delivery
Type B: normal oxygen delivery but mitochondrial function impaired (eg. sepsis, DM, neoplasia, drugs, toxins)

Question 22

What is the correct range for renal, myocardial and cerebral perfusion?

Answer 22

Renal 70-130 mmHg
Myocardial 60-140 mmHg
Cerebral 50-180 mmHg

Question 23

What type of catheter is the gold standard to measure cardiac output?

Answer 23

Swan Ganz

Question 24

What is critical illness-related corticosteroid insufficiency

Answer 24

A condition of functional hypothalamic-pituitary-adrenal axis insufficiency

Cortisol levels may be normal or high but adrenal response to ACTH stimulation is blunted