Deep body temperature from aural canal with servo-controlled heating to outer ear

Area of Science:

• Physiology
• Biomedical Engineering
• Thermometry

Background:

• Accurate core body temperature measurement is crucial for clinical assessment.
• Esophageal temperature is a gold standard but invasive.
• Non-invasive methods require validation for accuracy and reliability.

Purpose of the Study:

• To evaluate a portable, battery-powered device for measuring external aural canal temperature.
• To assess the device's ability to maintain a stable ear temperature for accurate core body temperature readings.
• To compare aural canal temperature measurements with esophageal temperature under varying environmental conditions.

Main Methods:

• A portable device utilized two thermistors: one for aural canal temperature and another for servo-controlled outer ear heating.
• Experiments were conducted on 18 human subjects (11 male, 7 female) in moving air ranging from 18 to 45°C.
• Aural canal temperature was compared against esophageal temperature, with rectal temperature monitored in cold air.

Main Results:

• The device stabilized aural canal temperature within 0.35°C of esophageal temperature in moving air (18-45°C).
• Stabilization occurred in colder air but was slower after brief cold exposure.
• Aural temperature paralleled esophageal temperature during rapid core body temperature changes, unlike rectal temperature in cold air.

Conclusions:

• The portable aural canal thermistor device provides a reliable, non-invasive method for estimating core body temperature.
• The device demonstrates accuracy comparable to esophageal temperature measurement under controlled conditions.
• This technology offers a promising alternative for continuous and accurate core body temperature monitoring in clinical and research settings.