S10 Review and some key bits

Question 1

How to work out arterial blood gas
- equations

Answer 1

Question 2

Things to remember:

• Can the body overcompensate?
• Normal pH?
• What is the acidotic and alkalotic ranges

Answer 2

Question 3

Anion gap - equation, what is the anion gap? normal range? Elevated AG suggests what?

In what metabolic acidosis is there NO anion gap?

Answer 3

Anion gap: (Na⁺ + K⁺) - (HCO₃^- + Cl^-)
Anion gap - pic

• Gastrointestinal bicarbonate loss
• Diarrhoea (especially secretory)
• High-output fistulas, pancreatic/biliary drainage
• Renal insufficiency (Kidney synthesises bicarbonate)

Question 4

How will the kidney respond to the loss of H+ ions in vomitus?

Answer 4

Question 5

How does vomiting change electrolytes?

How does diarrhoea leads to change in electrolytes?

Dehydration leads to which acid production?

Sepsis - how does this affect acid production?

Contents of small bowel and large intestine are acidotic or alkalotic?

Answer 5

Vomitting: Loss of H+ ions in the vomit

Diarrhoea: Leads to loss of HCO₃^-

Dehydration: Hypotension ->leads to poor tissue perfusion -> lactic acid production

Sepsis: Tissue hypo-perfusion -> Leads to lactic acid production

Contents of small bowel and large intestine are acidotic or alkalotic?
VERY rich in BICARBONATE

Question 6

CO₂ in Blood:

• pH is determined by the ratio of what?
• Where is most of the bicarbonate formed?
• What ‘mops up’ the H+?

Answer 6

Question 7

Respiratory acidosis:

• What is this?
• How does it effect the ratio?
• Causes

Answer 7

Question 8

Metabolic acidosis with respiratory compensation

Answer 8

Question 9

Renal compensation of respiratory acidosis is by reacovery and creation of HCO₃^-

Answer 9

Question 10

Anion gap

Answer 10

Question 11

Increased anion gap seen in metabolic acidosis (some types)

Answer 11