Prediction of rectal temperature from ear canal temperature

Area of Science:

• Occupational Health and Safety
• Environmental Physiology
• Biomedical Engineering

Background:

• Personal heat strain monitoring is vital for worker safety and productivity in hot environments.
• Accurate core body temperature prediction is essential for effective heat stress management.
• Aural canal temperature is a potential non-invasive indicator of core temperature.

Purpose of the Study:

• To compare methods for reducing environmental effects on aural canal temperature.
• To reduce the predictive error of a personal heat stress monitor (QST) and a simple ear thermistor (EAR).
• To assess the accuracy of aural temperature as a predictor of core body temperature.

Main Methods:

• Subjects wore impermeable protective clothing (PC) in a 30.1°C WBGT environment.
• Three conditions were tested: ear plugs (PLG), ear moulds (MLD), and ear moulds with earmuffs (MFS).
• Rectal temperature was the criterion measure, with QST and EAR used for prediction.

Main Results:

• While group predictions were satisfactory, the QST's individual predictive ability was impaired (SD ±0.36).
• A simple ear thermistor (EAR) demonstrated slightly better accuracy (SD ±0.28) in predicting rectal temperature.
• Aural temperature predictions extended safe work times beyond ACGIH guidelines.

Conclusions:

• A simple ear thermistor shows promise as a more accurate predictor of core body temperature than the QST.
• Further research is needed to validate aural temperature-based predictions across diverse conditions and populations.
• Improved heat stress monitoring can enhance worker safety and productivity in demanding occupational settings.