Temperature

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.

In addition to temperature, the nurse should recognize other objective cues that are often associated with alterations in temperature like chills, sweating, purulent drainage from a wound, lab results showing elevated white blood cells, or WBCs, as well as subjective cues like fatigue and pain.

Next, the nurse analyzes the cues by determining the relationship between the cues and linking them to the patient's history and clinical presentation. For example, the nurse will consider whether an elevated WBC count, chills, and nausea are consistent with an infection and fever; or if thirst, anorexia, and recent exposure to hot weather are consistent with hyperthermia.

Then, the nurse will determine a priority hypothesis related to altered temperature, such as hypothermia, hyperthermia, or fever. The nurse will rank the hypothesis by considering whether the findings are potentially life-threatening, like hypothermia or heatstroke; or an immediate concern, like fever. Based on this information, the nurse will address the most serious hypotheses first, and then generate solutions, such as "The patient's temperature will return to the expected range within 2 hours of treatment."

Okay, once the solutions have been generated, the nurse will take action to implement the solutions. For patients with fever, the nurse will administer fluids, antipyretics, and antibiotics. For patients with hypothermia, the nurse will use warmed blankets, warmed IV fluids, and head coverings to gradually warm the patient.

Lastly, the nurse will evaluate whether the expected outcomes have been met by reassessing the patient's temperature, to determine whether the patient's condition is improving, declining, or remaining unchanged. If the patient's condition is declining or hasn't changed, the nurse will revise the plan of care accordingly and take additional actions to guide care.

Alright, as a quick recap.... Temperature is a vital sign that reflects the body's ability to maintain thermoregulation. When measuring a patient's temperature, nurses will go through the steps of the Clinical Judgment Measurement Model to make clinical decisions about patient care by recognizing and analyzing cues, prioritizing hypotheses, generating solutions, taking action, and evaluating outcomes.