ABGs

Question 1

What are some causes of respiratory acidosis?

Answer 1

CNS depression (anaesthetics, narcotics)
CNS disease (trauma, haemorrhage, tumour)
Neurological disease (spinal cord lesion)
Mechanical (pneumothorax, myopathies, pleural effusion)
Pulmonary disease (COPD, PE)

Question 2

What are some causes of respiratory alkalosis?

Answer 2

Central (head injury, stroke, hyperventilation, sepsis)
Pulmonary (PE, pneumonia, asthma, pulmonary oedema)
Iatrogenic (excessive mechanical ventilation)

Question 3

What are some causes of metabolic acidosis?

Answer 3

Increased acid formation (ketoacidosis, lactic acidosis, poisoning)
Decreased acid excretion (uraemia)
Loss of bicarb (GI, renal)
Acid ingestion

Question 4

What are some causes of metabolic alkalosis?

Answer 4

Administration of bicarb
K+ depletion
Loss of H+ (vomiting)

Question 5

What does aspirin overdose look like on an ABG?

Answer 5

Initially respiratory alkalosis

Followed by metabolic acidosis