Arterial Blood Gases. Test Overview. An arterial blood gas (ABG) test measures the acidity (pH) and the levels of oxygen and carbon dioxide in the blood from an artery. This test is used to check how well your lungs are able to move oxygen into the blood and remove carbon dioxide from the blood.
How Often the Test Is Done During Your Pregnancy. Your doctor may use the Doppler often to listen to your baby's heartbeat during routine checkups, starting at about 8 to 10 weeks. Handheld Dopplers will not work quite this early.
Full Answer. Doctors use a stethoscope to listen to a patient's heartbeat according to the St. Louis Children's Hospital. The otoscope is used to examine a patient's nose and ears, while the ophthalmoscope is used to examine the eyes. The sphygmomanometer cuff is placed around the upper arm to measure blood pressure.