Engineering a Core Temperature Monitoring System to Support Patient Care at Risk of Exertional Heat Stress

Abstract

In Phoenix temperatures can reach up to 125°F and heat stroke is a life-threatening emergency routinely faced by the local fire department. EMS staff must treat patients in mobile ice baths, requiring quick and accurate core temperature readings. Current thermometers lack the accuracy, speed, and temperature ranges necessary for early intervention. While esophageal thermometers provide clinical grade measurements, current probes are difficult to position during field airway management, creating a clinical gap for an optimized solution.

Our concept is an enhanced esophageal temperature monitoring system designed for field use. The core innovation is a redesigned flexible shaping wire embedded into the catheter structure which plugs into the probe. This inclusion allows firefighters to guide and position the probe properly. It improves usability, accuracy, and response time in stressful field conditions. The probe will interface with a handheld monitor with rapid temperature updates and an alert system for temperatures reaching certain values.

The product is engineered with design specifications identified from field research, clinical interviews and a HOQ analysis. These specifications include a ±0.2 °C accuracy, ≤5-second update frequency, IP67 water and sweat resistance, 1-meter drop tolerance, ≤30-second application time, ≥12-hour battery life, and EMS data integration. The current development is guided by a first order thermal model, predictive digital filtering system, airflow bias correction and environmental heat exchange analysis to ensure the best performance in field conditions.

The design prioritizes a low cost solution for scalability within Phoenix and local neighborhoods.

The disposable probe uses ISO-10993 compliant polymers, an off-the-shelf thermistor, and low-cost shaping wire for an estimated manufacturing cost of $2.50. The complementary reusable monitor features a compatible processing system with waterproof housing, costing $40 to manufacture. These preliminary cost predictions support an affordable and reusable system, suitable for municipal EMS budgets.

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