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.
Information. Auscultation is usually done using a tool called a stethoscope. Health care providers routinely listen to a patient's lungs, heart, and intestines to evaluate the frequency, intensity, duration, number, and quality of sounds. Health care providers also use auscultation to listen to the heart sounds of unborn infants. This can be performed with a stethoscope or with sound waves (called Doppler ultrasound). It can also be used to hear pulses in the arms and legs.