ABG Flashcards
1
Q
Step 1
A
Look at the oxygen levels, if their PaO2 <8kPa on 21% oxygen (room air) then they are in respiratory failure
2
Q
What should PaO2 be?
A
Approximately 10kPa less than inspired oxygen
3
Q
Step 2
A
- Look at hydrogen ions/pH
* Are the acidotic, alkalotic or neutral
4
Q
Step 3
A
- Is carbon dioxide high low or normal
- If high -> more acid in the blood and it is likely a primary respiratory problem
- If low -> PaCO2 low -> less acid in the blood either a primary respiratory or compensation
5
Q
Step 4
A
- Is bicarbonate high, low, or normal?
- If high -> more alkali in blood
- If low -> less alkali in the blood (more likely to be a primary metabolic problem, less often compensation)
6
Q
Metabolic acidosis
A
- H+ will be high
- bicarbonate will be low
- If there is compensation, CO2 will be low
7
Q
Metabolic alkalosis
A
- Low H+
- High HCO3
- If compensation then high CO2
8
Q
Respiratory acidosis
A
- H+ will be high
- CO2 will be high
- HCO3- will be high if there is compensation
9
Q
Respiratory alkalosis
A
- H+ will be low
- pCO2 will be low
- HCO3 will be low if there is compensation
10
Q
What is type 1 respiratory failure?
A
Low PaO2 but normal oxygen
11
Q
What is type 2 respiratory failure?
A
Low PaO2 with a high PaCO2
12
Q
What are the causes of type 1 respiratory failure?
A
- Pneumonia
- Pulmonary oedema
- Pulmonary embolism
- Pulmonary fibrosis
13
Q
What are the causes of type 2 respiratory failure?
A
- COPD
- Neuromuscular disease/severe kyphoscoliosis
- Obesity hypoventilation
14
Q
What is the clinical use of anion gap?
A
In the differential diagnosis of metabolic acidosis
15
Q
What are the causes of a metabolic acidosis with a raised anion gap?
A
- Renal failure
- Diabetic or other ketoacidosis
- Lactic acidosis
- Toxins e.g. salicylate
