Copyright Goodheart-Willcox Co., Inc. Chapter 18 Vital Signs, Height, and Weight 457 If a resident has been sleeping or resting on the ear, this can generate heat. Use the other ear to ensure an accurate reading. Always check that you are using the best and safest location to take a temperature for each resident. Average Body Temperatures A resident’s temperature may change slightly (by 1°F) during the day due to exertion, how much a resident eats or drinks, and external temperature. The normal, or average, temperature for an adult is 98.6°F (37.0°C), although the average range is 97.0–99.0°F (36.5–37.2°C). The average rectal temperature is approximately 1°F (0.6°C) higher than the average oral temperature, and axillary and temporal artery temperatures can be 1°F (0.6°C) lower. Hypothermia, while not seen often, is a body temperature below 95°F (35°C). Average temperature ranges also vary based on a resident’s age and the type of thermometer used (Figure 18.3). Types of Thermometers Several different types of thermometers help measure temperature. Some thermom- eters are filled with a liquid that is usually colored alcohol. These are nondigital, or manual, thermometers. Some thermometers contain a plastic strip (usually disposable) with liquid crystals that change color to indicate different temperatures. Others are electronic and use digital displays. Healthcare facilities may use any of these temperature devices. No matter what device is used, all types of thermometers have the same purpose. Therefore, it is best to learn about them all. Nondigital Thermometers Nondigital thermometers can be used to take oral, rectal, or axillary temperatures. Figure 18.1 earlier in this section shows a nondigital thermometer. These thermometers are tubes filled with a liquid (colored alcohol) that expands and moves up or down in response to heat. The bulb at the end of the thermometer is inserted into the body. The bulb of a rectal thermometer is thicker and broader than the bulb of an oral thermometer. Some thermometers are marked with a colored dot—blue for oral or axillary, and red for rectal. It is important to correctly place each thermometer and leave it in for the prescribed amount of time. Use the following guidelines based on the type of thermometer: • Oral temperatures: insert the thermometer under the tongue and ask the resident to close his or her mouth completely while breathing through the nose. Leave the thermometer in for three minutes. Think About This Physicist Daniel Gabriel Fahrenheit invented the first thermometer in the early eighteenth century. The first thermometer was made of glass and contained a hollow stem marked with a calibrated temperature scale and a small bulb at its base. The thermometer was filled with pressurized liquid mercury. Mercury was chosen because it rises and falls in response to temperature changes. By using the thermometer and reading the calibrated temperature scale, one could determine how hot or cold a person was. Mercury thermometers are no longer used because mercury is a toxic substance. If a mercury thermometer broke and released the mercury, it could cause blindness, memory loss, and deafness, among other symptoms. Average Ranges of Body Temperature Thermometer Birth to Two Years Three to Eleven Years Twelve Years and Older Oral Should not be taken 97.0°F–99.5°F (36.1°C–37.5°C) 97.6°F–99.6°F (36.4°C–37.5°C) Rectal 97.0°F–100.4°F (36.1°C–38.0°C) 97.9°F–100.4°F (36.6°C–38.0°C) 98.6°F–100.6°F (37.0°C–38.1°C) Tympanic Should not be taken 98.0°F–99.6°F (36.7°C–37.5°C) 98.6°F–100.4°F (37.0°C–38.0°C) Axillary 97.5°F–99.3°F (36.4°C–37.4°C) 96.6°F–99.0°F (36.0°C–37.2°C) 96.6°F–98.6°F (35.9°C–37.0°C) Temporal Artery 98.3°F–100.3°F (36.8°C–37.9°C) 97.8°F–100.1°F (36.5°C–37.8°C) 97.2°F–100.1°F (36.2°C–37.8°C) Figure 18.3 The average temperature ranges for infants, children, and adults are shown here.