Temperature Monitoring

Body temperature changes can lead to abnormal functioning of the organs and enzyme systems of the body. Patients receiving anesthesia are prone to temperature changes due to multiple causes and mechanisms. Thermoregulation, mediated by hypothalamus, ensures normal body temperature to be maintained within a narrow range. Incidence of hypothermia is common during general anesthesia. Mechanisms include anesthetic-induced impaired thermoregulation that causes vasodilation, inhibit vasoconstriction, and reduce metabolic rate and exposure to cold environment. Different factors often lead to a potentially dangerous clinical paradox in patients under regional anesthesia: a hypothermic patient who denies feeling cold. Although a variety of technologies (like thermistor, liquid crystal, thermocouple, platinum wire, infrared thermometer, mercury thermometer, etc.) are available to measure temperature, none is suitable for all situations. The preferred site for temperature monitoring (like skin, forehead, axilla, mouth, rectum, pulmonary artery, bladder, nasopharynx, esophagus, hypopharynx, etc.) depends on the indication, surgical procedure, duration, access, and availability of equipment. Core temperature monitoring should be considered during general anesthesia for long duration surgeries, anticipated risks of massive blood loss, malignant hyperthermia by virtue of history or evaluation, deliberate hypothermia, elderly, ASA 3 and 4 physical status, and children.