Step 6: Evacuate air from the syringe


The syringe is then carefully inspected for air. (Air in the syringe can affect the results of the ABG by raising the PO2.) There should be a continuous column of blood up to the hub of the needle. Evacuate air from the syringe by tapping the syringe and depressing the plunger. The syringe is then capped, labeled and placed in a bag with ice before being sent for analysis.