Related Experiment Videos
Heat loss in exposed volunteers
M J English1, C Farmer, W A Scott
1Department of Anaesthesia, Montreal General Hospital, Quebec, Canada.
The Journal of Trauma
|April 1, 1990
Summary
Hypothermia during surgery is a risk. Direct heat exchange measurements show radiation and convection cause significant heat loss. Thermal mattresses can effectively counteract this by increasing heat production.
Area of Science:
- Physiology
- Biomedical Engineering
Background:
- Hypothermia is a frequent complication following major surgery and trauma.
- Understanding human body heat exchange is crucial for patient safety.
Purpose of the Study:
- To directly measure heat exchange between volunteers and the environment.
- To quantify heat loss and gain coefficients during simulated clinical conditions.
Main Methods:
- Utilized Heat Flux Transducers to measure heat exchange.
- Measured radiation, convection, and conduction from exposed volunteers.
- Assessed heat exchange with a thermal mattress (CSZ, Blanketrol II).
Main Results:
- Determined coefficients for radiation (6.6), convection (8.3√v), combined radiation/convection (9.7), and conductance (41 W/m².°C).
- Heat loss via radiation and convection alone is 10 W/m².°C.
- A >4°C gradient causes heat loss exceeding production (40 W/m² under anesthesia).
Conclusions:
- Directly measured heat exchange provides critical data for managing perioperative hypothermia.
- Thermal mattresses can significantly augment heat production, potentially doubling it.
- Findings highlight the importance of active warming to prevent heat loss exceeding metabolic production.