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Temperature reflects the body’s ability to regulate body heat, a process called thermoregulation. When measuring a patient’s temperature, the nurse should follow the steps of the Clinical Judgment Measurement Model or CJMM to make clinical decisions about patient care. Before we cover how temperature relates to clinical judgment though, let’s review physiological regulation of body temperature.

Now, the body works to maintain a consistent internal temperature through a part of the brain called the hypothalamus, which acts like the body’s own personal thermostat by controlling the body’s set point, or normal core temperature. When the hypothalamus senses that the temperature is increasing above the set point, it promotes heat loss by initiating sweating and vasodilation. Likewise, when the temperature goes below the set point, the hypothalamus initiates vasoconstriction, which reduces heat loss, and rhythmic muscle tremors, or shivering, to generate heat. So, if the hypothalamus is impacted by disease or trauma, the normal thermoregulatory process can become impaired.

In addition, other biological processes can affect body temperature. For example, the body’s normal biological clock, called the circadian rhythm, affects temperature by causing it to peak in the late afternoon, and decrease at night as the body prepares for sleep. Then, just before waking up, body temperature begins to rise again.

Okay so, the primary source of heat production in the body is through metabolism, which is the chemical process that produces energy for cellular functions. However, the body temperature can increase above normal in patients with a fever, which is where the thermostat’s set point is raised higher due to problems like infection, inflammation, or trauma. Body temperature can also increase with hyperthermia. This is where the thermostat set point remains normal, but the body’s thermoregulatory processes become overwhelmed and ineffective from prolonged exposure to extreme heat.

Now, body heat can also be lost through four processes. First is radiation, or heat loss through waves or energy particles, which can occur when the ambient temperature is lower than body temperature, causing heat to be lost to the environment. The next process is conduction, or heat loss through direct contact. Conductive heat loss can occur when a person jumps into a cold pool or lies on a cold surface. On the other hand, convection is when heat is lost through movement of air or water, like when a person sits in front of a fan. Finally, heat can be lost by evaporation, which is when liquid changes to a vapor, like when a person sweats. Excessive heat loss can cause hypothermia or even frostbite.

Alright, when assessing a patient’s temperature, the nurse will use the Clinical Judgment Measurement Model to gather and recognize important cues. These can include the expected temperature range, which can vary based on whether the nurse takes an oral, axillary, rectal, or temporal temperature, as well as the patient’s age and condition.