Taking a patient’s temperature is an initial part of a full clinical examination. The moment the medical provider comes within inches of the patient’s skin, they can tell if there is a change in the patient’s temperature. Heat radiates from a febrile patient, skin becomes clammy when cardiac output is reduced, and cold skin can be an ominous sign when combined with other negative findings. Temperature is an important indicator for patient status.
How the Temperature is Attained
There are several locations where temperature can be attained on the patient. The means at which it is taken may depend on the patient anatomy, age, complaint or need for accuracy of core temperature.
• In the anus (rectal) 99.5
• In the mouth (oral) 98.6
• Under the arm (axillary) 97.7
• In the ear (tympanic) 99.5
• In the vagina (vaginal) 99.5
• On the skin of the forehead
• Over the temporal artery (temporal)
What Tools are Used
Typically glass thermometers are not used today except for in cases of hypothermia. The basic thermometers used today are plastic with a metal sensor in the end and a digital display. These plastic thermometers are used for rectal, axillary, vaginal and oral temperatures.
Another type is a plastic strip that is placed across the forehead. The strip gives an approximate range of temperature and outside factors such as room temperature, wind, and light source can affect the reading.
Tympanic thermometers are based on the thought that the eardrum closely mirrors the body’s core temperature. They work by detecting the heat emission from the tympanic membrane onto an infrared detector.
What a Temperature Can Indicate
Whenever there is a variance in the body temperature the first consideration is fever. Fever is a raise in the body’s temperature as a by-product of the inflammatory response in the body. Infection is the primary cause of fever and can be systemic or local. For example, if a patient were to have an upper respiratory then they would have a fever which would reflect in any means of measurement. Whether it was an oral, rectal, or tympanic measurement, the fever would register. On the other hand, if a patient had an insect bite that had become infected, then the fever may only be felt at the site of the bite.
Hyper and Hypothermia
Exposure to the environment with changes in temperature, wind, and humidity can lead to an unhealthy core temperature. The body can function within a range but once outside of that range, the change can cause functions to suffer or cease.
Hyperthermia is a state the body reaches when it is taking in and keeping heat causing the core temperature to increase. It is usually caused by prolonged exposure to high temperatures without convection. The hypothalamus, which regulates the body’s temperature, can no longer control the temperature and stops regulating all together. This can lead to a life-threatening emergency that will require hospital interventions if not treated at early onset.
Hypothermia is just the opposite and occurs when a body core temperature decreases to the point that it affects the body’s function. It usually is a result of exposure to cold temperatures, water or wind. As the temperature drops starting at two degrees, the dangers increase to the point of cardiac arrest.
Removing the patient from the environment is the first intervention that should be implemented in both cases.
Image Caption: Chart showing diurnal variation in body temperature, ranging from about 37.5° C. from 10 A.M. to 6 P.M., and falling to about 36.3° C. Credit: Encyclopædia Britannica/Wikipedia