The heart, lungs, and brain are vital organs. Blood flow to these organs is normally rich. During illness, blood flow to less essential areas slows to ensure that the vital organs are supplied and protected. The ideal location for measuring temperature is in the heart, but doing so is not possible. The temporal artery is a major artery in the head. This is the only major artery in the body that is close enough to the surface of the skin to obtain an accurate temperature. The temporal artery is also close to the heart and has a high blood flow, making it well suited for measuring temperature.
The temporal artery thermometer (TAT) is battery-operated. It measures temperature of the skin surface over the temporal artery. The temporal artery thermometer has a wider range than other types of clinical thermometers, and can measure temperatures from 60°F to 107.5°F. This is especially helpful for monitoring patients with below-normal temperatures or cold exposure. Special error codes will appear on the screen to alert the user to values that are dangerously high or low. When using the temporal artery thermometer, measure an area of the head that is not covered by a hat or blanket. If the patient’s head has been covered, wait at least 10 minutes for it to cool before proceeding.
In a stable patient, the temporal artery temperature is approximately 0.8°F higher than an oral temperature, and is about the same as a rectal temperature. If the patient has a fever, the difference may be greater. This thermometer is more accurate than other types because it is subject to less interference. Many factors interfere with the ability to obtain an accurate oral or rectal value during acute illness.
Procedure Measuring a Temporal Artery Temperature
Note: The guidelines for this procedure vary slightly from state to state, and from one facility to the next. Your instructor will inform you if the sequence in your state or facility differs from the procedure listed here. Know and follow the required sequence for your facility and state.
1. Carry out initial procedure actions.
2. Assemble equipment:
Disposable gloves if there may be contact with blood or body fluids, open lesions, or wet linens. (Gloves are not necessary unless required by facility policy or potential exposure to body fluids.)
3. Check the lens to make sure it is clean and intact.
4. Apply a clean probe cover, or wipe the probe with alcohol or a disinfectant wipe.
5. Hold the thermometer as you would a pencil or pen. Gently press the probe (head) of the thermometer against the center of the patient’s forehead. Push the switch to the “ON” position with your thumb. Keep this button depressed.
6. Slowly move the probe across the forehead to the hair line on one side of the head.
7. Push the hair back slightly with the opposite hand, if needed, then lift the probe slightly. Quickly place the probe down just behind the ear lobe on the neck. (Use the area in which perfume is usually applied.) Release the button and remove the thermometer. Note and remember the value on the digital display. The value should remain on the display for about 30 seconds before disappearing. See the following table for normal ranges of temporal artery temperatures by age group.
8. Discard the disposable probe cover, or wipe the probe with an alcohol or disinfectant wipe, according to facility policy.