Monitoring body temperature.

Vigilant and accurate assessment of thermal balance is imperative with the critically ill. Disease, injury, or pharmacologic activity can impair thermoregulation, leaving patients vulnerable to uncontrolled gain or loss of heat. Body temperature provides cues to onset of infection, inflammation, and antigenic responses, as well as indicating efficacy of treatment. With knowledge of heat transfer principles, physiologic processes that distribute body heat, and principles of thermometry, the nurse is better equipped to make reasoned clinical judgment about this important vital sign. Choices of instruments or measurement sites are influenced by needs to estimate either hypothalamic temperature or shifts in body heat. Need for continuous versus episodic assessment, availability or intrusiveness of equipment, and stability of the patient also influence choices. Monitoring devices, measurement sites and techniques, equipment limitations and precautions are discussed. Interpretation and application of assessment findings are presented as they relate to abnormally high or low temperatures, patterns of fever, and temperature gradients.