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.
A Holter monitor is a device that continuously records your heartâs rhythm during daily activities (usually for 24 hours). This is also called an ambulatory electrocardiogram.The monitor records your heartâs rhythm through electrodes that are placed on your chest.Electrodes are small adheive patches attached by wires to a monitor. This test helps show how your heart responds to normal activity or to certain medications.his is also called an ambulatory electrocardiogram. The monitor records your heartâs rhythm through electrodes that are placed on your chest. Electrodes are small adheive patches attached by wires to a monitor.