ABGs

Question 1

How can you determine whether an acid base disturbance is respiratory or metabolic?

Answer 1

If the pH and pCO2 are moving in the same direction (either both high or both low) then it is metabolic. If they move in opposite directions then it is a respiratory cause.

Question 2

How can a metabolic acidosis occur?

Answer 2

DKA, lactic acidosis, aspirin overload or renal failure. Diarrhoea

Question 3

What are some causes of metabolic alkalosis?

Answer 3

GI losses of H+ (vomiting mainly, sometimes diarrhoea),

Renal loss of H+ ions (diuretics).

Question 4

Explain how sepsis affects ABGs

Answer 4

Sepsis can cause reduced end organ perfusion which will cause tissue hypoxia. This results in anaerobic respiration with accumulation of lactic acid. Resulting in lactic acidosis.

Question 5

Explain how DKA affects ABGs

Answer 5

Absence of insulin, causes reduced glucose into cells so there is release of FFA which are converted into ketone bodies which causes the blood to become more acidic.

Question 6

What are some causes of mixed respiratory and metabolic acidosis?

Answer 6

Cardiac arrest and multi-organ failure

Question 7

What are some causes of mixed respiratory and metabolic alkalosis?

Answer 7

Liver cirrhosis and diuretic use,
hyperemesis gravidarum,
excessive ventilation in COPD