Your doctor will perform a physical examination. This should involve listening to your lungs and heart using a stethoscope and examining your skin for any hints of a blue color. Your doctor will also ask whether you have any conditions that can cause respiratory failure.
In order to diagnose respiratory failure, your doctor will need to check the amount of oxygen in your blood. There are two tests that can be used to do this:
- Pulse oximetry: this test uses a small sensor that attaches to the finger or ear. It uses light to estimate how much oxygen is present in the blood.
- Blood gas test: this test involves taking a small arterial blood sample and sending it to a laboratory to measure the oxygen and carbon dioxide levels in the blood. This test is more accurate than pulse oximetry.
Your doctor may use other tests in order to determine the underlying cause of respiratory failure, such as a chest X-ray, CT scan, echocardiogram or electrocardiogram.