Acid Base 2

Question 1

What can cause hyperventilation? [3]

(and therefore resp. alkalosis)

Answer 1

• Any cause of impaired oxygenation !! Important (This is because these people frequently breathe faster than normal when trying to get more oxygen into the body)
• Central cerebral stimulation: fever, pain, drugs, sepsis
• Panic/anxiety

Question 2

What can cause resp. acidaemia? [3]

Answer 2

** Reduced ventilation:**
* Airways disease: COPD
* Neuromuscular or chest wall disease
* Reduced respiratory drive: opiates or reduced consciousness

Question 3

What are o2 sat. targets for COPD Ptx? [1]

Answer 3

88-92

Question 4

What are the characteristics of compensated resp acidosis? [3]

Answer 4

• Normal pH
• high pCO2
• compensatory high HCO3-

Question 5

Why would someone commonly present with metabolic acidosis with partial resp. compensation? [1]

Answer 5

Diabetic patient: have DKA - causes ketoacidosis

Question 6

What could cause high anion gap metabolic acidosis? [4]

Answer 6

Acid ‘added’ to the blood:

Ketones:
* DKA
* Starvation or alcoholic ketoacidosis

Lactate:
* Tissue hypoxia/poor perfusion
* Altered cellular respiration
* Rarely: D-lactate

‘Titrable acid’
* Renal failure

Ingested acid
* Ethylene glycol, methanol, salicylate…

Question 7

What does lactic acidosis / ketoacidosis commonly present as? [3]

Answer 7

Low pH, low HCO3-, often low CO2

Question 7

What does lactic acidosis / ketoacidosis commonly present as? [3]

Answer 7

Low pH, low HCO3-, often low CO2

Question 8

What happens to serum K+ levels in severe acidosis?

Answer 8

Go up (as exchange of H+ causes to go otherway)

Question 9

What are normal anion gap, metabolic acidosis characterised by? [1]

Answer 9

Increased Chlorine levels / = ‘Hyperchloraemic metabolic acidosis’

Compensatory rise in chloride to maintain electrical neutrality

Hes losing bicarbonate

Question 10

What would cause normal anion gap metabolic acidosis?

Answer 10

= ‘Hyperchloraemic metabolic acidosis’
Usually due to bicarbonate loss
* Kidneys: Renal tubular acidosis
* Gut: diarrhoea

Compensatory rise in chloride to maintain electrical neutrality

Question 11

Why might HCO3- rise in Ptxs?

Answer 11

As H+ is lost:
* Diarrhoea
* Diuretics
* Mineralocorticoid excess
* Vomiting/NG drainage

As H+ moves into cells: Hypokalaemia