ABG interpretation Flashcards
What is the normal pH of blood?
7.35 - 7.45
What is a normal PaCO2?
4.7 – 6.0 kPa
What is a normal PO2?
11 – 13 kPa
What is a normal HCO3-?
22-26 mmol/l
What is a normal base excess?
-2 to +2 mmol/l
When looking at an ABG, what question should be asked first?
Is this patient hypoxic?
What should the PaO2 be for a patient on room air?
> 10 kPa
What should the PaO2 be for a patient on oxygen therapy?
10kPa less than the % inspired concentration FiO2
What type of mask will give an accurate concentration of oxygen to the patient regardless of the oxygen flow rate?
venturi mask
What % oxygen is given with
a) 1L/min?
b) 2L/min?
c) 3L/min?
d) 4L/min?
a) 24%
b) 28%
c) 32%
d) 36%
Which PaO2 indicates severe hypoxiaemia and respiratory failure for a patient on room air?
<8 kPa
Which type of respiratory failure has hypercapnia?
type 2
Which type of respiratory failure has normocapnia?
type 1
What is type 1 respiratory failure the result of?
V/Q mismatch
What is V/Q mismatch?
a mismatch of ventilation to perfusion ie. the volume of air going into the lungs doesn’t correlate with the volume of blood flowing into the lungs
Give some causes of type 1 respiratory failure
pulmonary oedema
pulmonary embolism
bronchoconstriction
Why does type 2 respiratory failure occur?
alveolar hypoventilation
Why might alveolar hypoventilation occur?
- increased resistance due to airway obstruction eg. COPD
- reduced compliance of chest wall or lung tissue eg. fracture, obesity
- reduced muscle strength eg. MND, guillain-barre
- drugs acting on respiratory centre eg. opiates
An imbalance in what causes a respiratory driven acidosis/alkalosis?
CO2
An imbalance in what causes a metabolism driven acidosis/alkalosis?
HCO3-