221. Warming Devices Flashcards
What are the four main mechanisms of heat transfer?
- Radiation
- Conduction
- Convection
- Evaporation
What percentage of total heat loss does radiation account for during the perioperative period?
Roughly 60%
What is the primary source of heat loss in pediatric patients?
Radiation due to their larger body surface area to body mass ratio
How can radiant heat loss be minimized in the operating room?
By raising the temperature of the operating room
What are overhead radiant warmers and their effectiveness?
Devices that produce infrared radiation to warm the patient; highly effective for smaller pediatric patients and neonates
What is conduction?
The direct transfer of heat from two objects that are touching
How can conductive heat loss be prevented when a patient is on a cold operating room table?
By prewarming the table
What is a common method to reduce heat loss through conduction?
Adding layers of insulation such as blankets and surgical drapes
What is the single most effective warming method during surgery?
Cardiopulmonary bypass (CPB)
What is convection?
The transfer of heat through moving molecules in gases or liquids
What are forced air warmers and their primary function?
Devices that generate a warm air current to warm a patient; most effective noninvasive warming method
What percentage of heat loss is accounted for by evaporation during surgery?
10%–20%
What is a heat and moisture exchanger (HME)?
A passive filter that traps moisture and heat during expiration for recycling during inspiration
Why are pediatric patients particularly susceptible to burns and hyperthermia?
Due to their sensitivity and the use of warming devices
What should be monitored continuously to prevent iatrogenic hyperthermia?
Core temperature
