What is an Arterial Blood Gas?

Blood gases are a group of analyses of the blood that is collected by puncturing the radial artery of the wrist using local anaesthesia.

They enable the amount of oxygen, carbon dioxide, and the pH to be measured in the blood. They help to diagnose, and to establish the severity, as well as to follow-up the diseases that affect gas exchange, such as Chronic Obstructive Pulmonay Disease. 

They are often requested prior to thoracic or abdominal surgery, when the presence of respiratory disorders is suspected. They are also requested to assess the indication of home oxygen therapy and its follow-up.

They are done like any other blood test. The only difference is that local anaesthesia is given in order to reduce or eliminate the feeling of pain that can be caused by the puncture.

The patient does not require any special preparation to do the test. Despite being a blood test, it is not necessary to be fasting.

If the patient carries oxygen and his/her doctor needs to know the amount of oxygen in the blood, the patient must disconnect the oxygen for 20 minutes prior to the analysis.

The blood gases are performed by health professionals trained in this type of analysis.

The chest physician is responsible for evaluating the results of the test and issues the corresponding report.

During the analysis, the patient is attended by the staff member who informs and accompanies him/her during the whole test procedure.

When the local anaesthesia is given, you may feel a slight burning sensation (very well tolerated by patients) and for the blood gas specimen, you may experience a slight prick as in routine blood tests.