ABG interpretation Flashcards
What does a low oxygen and high CO2 indicate?
type 2 respiratory failure
What does a low oxygen and normal/low CO2 indicate?
type 1 respiratory failure
What does a high PH, a high CO2 and high bicarbonate indicated?
Compensating Metabolic Alkalosis
What does a high pH, a normal CO2 and a high bicarbonate indicate?
uncompensated metabolic alkalosis
What are your thoughts on a normal PaO2 in a patient on high flow oxygen?
- this is abnormal as you would expect the patient to have a PaO2 well above the normal range with this level of oxygen therapy
What are your thoughts on a normal PaCO2 in a hypoxic asthmatic patient
(low PaO2 and normal PaCO2) is a sign they are tiring and need ITU intervention
What are your thoughts on a very low PaO2 in a patient who looks completely well, is not short of breath and has a normal O2 ?
likely to be a venous sample
What is your first question when looking at an ABG?
- is this patient hypoxic ? because this will kill them before anything else does
When is it ok to keep the patient on air
PaO2 > 10kPa keep on air in a healthy patient
What should the PaO2 be with a patient on oxygen therapy?
- PaO2 should be 10kPa less than the % inspired concentration / FiO2
When would the patient be hypoxic vs severely hypoxic?
If PaO2 <10kPa then hypoxic
If PaO2 < 8kPa then severely hypoxic and in resp failure
What causes type 2 resp failure?
alveolar hypoventilation due to:
- airway obstruction (COPD)
- reduced compliance of lung tissue / chest wall (pneumonia, fracture, obesity)
- reduced strength of resp muscles
- drugs acting on resp centre e.g.opiates
prevents patient from being able to adequately oxygenate and eliminate enough CO2 from blood
What is ABG results for respiratory acidosis?
- low pH
- high CO2
- normal bicarbonate
What is the ABG result for respiratory alkalosis?
- high pH
- low CO2
- normal bicarb
What is the ABG result for respiratory acidosis with metabolic compensation?
- low (normal) pH
- high CO2
- high bicarbonate
