Shock including Hypovolaemia

Question 1

Types of Shock

Answer 1

• hypovolaemia
  * blood loss, late stages of dehydration in gastroenteritis, severe diabetic ketoacidosis
  • vasodilatation
    
    • anaphylaxis, spinal shock, sepsis
  • cardiogenic cause
    
    • large acute myocardial infarction
  • obstruction to major vessels
    
    • tension pneumothorax, large pulmonary embolus

Question 2

Treatment of Shock

Answer 2

• Normal saline (0.9% sodium chloride)

Question 3

Hypovolaemia Definition

Answer 3

In a variety of disorders, fluid losses lead to depletion of the extracellular fluid. This problem, if severe, can lead to a potentially fatal decrease in tissue perfusion.

Question 4

Hypovolaemia Pathophysiology

Answer 4

True volume depletion occurs when fluid is lost from the extracellular fluid at a rate exceeding net intake. These losses may occur from the;

• Gastrointestinal tract, skin or lungs, Urine, Third space that is not in equilibrium with the extracellular fluid.

Question 5

Hypovolaemia Protective Mechanisms

Answer 5

When these losses occur two factors tend to protect against the development of hypovolaemia:

1. dietary sodium and water intake are generally far above basal needs
2. the kidney minimises further urinary losses by enhancing sodium and water reabsorption.

Question 6

Hypovolaemia Stages

Answer 6

Stage 1 - < 15% - 0.75L
Stage 2 - 15-30% - 0.75-1.5L
Stage 3 - 30-40% - 1.5-2L
Stage 4 - >40% - >2L

Question 7

Hypovolaemia Stages with correlated BP

Answer 7

Stage 1 & 2 - Normal
Stage 3 - Decreased
Stage 4 - Critical

Question 8

Hypovolaemia Stages with correlated Heart Rate

Answer 8

Stage 1 - < 100bpm
Stage 2 - 100-120bpm
Stage 3 - 120-140bpm
Stage 4 - >140bpm

Question 9

Hypovolaemia Stages with correlated Respiratory Rate

Answer 9

Stage 1 - 14-20
Stage 2 - 20-30
Stage 3 - 30-35
Stage 4 - >35

Question 10

Hypovolaemia Stages with correlated Urine (mL per hour)

Answer 10

mL per hour
Stage 1 - >30
Stage 2 - 20-30
Stage 3 - <20
Stage 4 - Negligible

Question 11

Hypovolaemia Stages with correlated CNS Symptoms

Answer 11

Stage 1 - Normal
Stage 2 - Anxious
Stage 3 - Confused
Stage 4 - Coma

Question 12

Compensated Hypovolaemic Shock

Answer 12

The cellular energy (ADH) needs are met by the combined aerobic and anaerobic supplies

Question 13

Uncompensated Hypovolaemic Shock

Answer 13

Irreversible damage occurs when
* aerobic + anaerobic supplies < cellular function demand

cellular function demand = critical oxygen delivery

Question 14

Tissue Resistance to Hypoxia

Answer 14

• Low resistance (few minutes of hypoxia)
  * Brain and gut cells permanent damage
  • Medium resistance (> 2.5 hours of ischaemia)
    
    • Hepatocytes
  • High resistance
    
    • Skeletal and smooth muscles

Question 15

Shock Causes

Answer 15

SHOCKED

• Sepsis or Spinal shock
• Hypovolemic/Hemorrhagic
• Obstructive
• Cardiogenic
• anaphylactiK
• Extra/other
• Drugs