- Lung disease - COPD, pneumonia, bronchiolitis, acute pulmonary oedema; anything that can reduce O2 uptake.
- Cyanotic congenital heart disease
- Some rare issue with haemoglobin
Clinical and Associated Features
Essentially, if they have some form of lung disease, you'll be able to tell. If they havea mental
If it's lung disease - high flow O2. If they do not respond to oxygen therapy, it reduces the likelihood of it being a lung cause.
If it's one of the other things, you probably need to something clever like major surgery (cyanotic heart disease) or blood transfusion (thalassaemia).