A valid use of skin temperature is with incubated newborns. Electronic sensing elements attached to the skin provide a digital readout showing the trend of neonates' temperature and automatically maintain optimal environmental temperature in the incubator. The esophagus Obviously an invasive site, the esophagus is used for measuring the temperature of anesthetized patients. Because temperatures taken at this site closely correlate to core temperature, many clinicians view this as the most accurate site for measuring body temperature in critical care, but it's too invasive to use for temperature alone. The bladder Bladder temperature is measured by a thermistor attached to an indwelling urinary catheter.
High correlation exists between bladder and PA temperature.
Finally, patients with hypothermia will show a slight lag in bladder temperature during rewarming. These two factors make the tympanic membrane both a constant source of hypothalamic temperature during homeostasis and the first accessible tissue to signal any changes in that temperature. The temperature of the tympanic membrane also is relatively well protected from the influence of ambient temperatures and is unaffected by respiration, eating, drinking, or smoking. And cross-contamination is unlikely, even from discarded, used probes, because the ear has no mucous membranes. Plus, of course, the ear has an equally usable twin on the other side of the head.