Reexamination of tympanic membrane temperature as a core temperature

Area of Science:

• Physiology
• Biomedical Engineering

Background:

• Tympanic temperature (Tty) measurement controversies exist regarding its accuracy for core body temperature.
• Previous studies show inconsistent effects of facial cooling/heating on Tty, limiting its clinical utility.

Purpose of the Study:

• To develop a safer, more reliable tympanic membrane probe.
• To investigate the causes of inconsistent Tty responses to facial thermal challenges.
• To validate Tty as an accurate measure of core body temperature.

Main Methods:

• Utilized a modified thermocouple probe with improved sensor design and insulation.
• Compared Tty measurements with esophageal temperature (Tes) under steady-state conditions.
• Assessed Tty and Tes responses to facial and scalp skin cooling and foot warming.

Main Results:

• Repositioning the probe sensor corrected Tty drops during facial cooling, indicating thermal contamination.
• A thermally insulated probe ring prevented Tty decreases during facial cooling, unlike a larger sensor area probe.
• Tty closely matched Tes in steady-state conditions (36.83°C vs. 36.87°C).
• Facial cooling minimally affected Tty and Tes.
• Tty detected temperature changes 5 minutes faster than Tes during foot warming.

Conclusions:

• A modified tympanic membrane probe design minimizes thermal contamination, enhancing reliability.
• Tympanic temperature is a valid and potentially superior measure of core body temperature compared to esophageal temperature.
• Further probe development could establish Tty as a standard for core body temperature monitoring.