Temperature Monitoring Flashcards
What is the dominant thermoregulatory site in humans?
Hypothalamus
Why is warming patients in the OR important?
- Warm patient do better- it’s a fact!
- reduce wound infections
- reduce blood loss (coagulation cascade?)
- reduce cardiac events
- shorten hospital stays
Thermoregulation: Afferent thermal sensing
- Many cells in the body are temperature sensors
Thermoregulation: Central regulation
“Set point” System - thermoregulatory responses are turned on and off in response to hypothalamic temperature
“Thermoregulatory model” - thermal input from tissues throughout the body are integrated together to coordinate a response to regulate temperature
Thermoregulation: Efferent responses
Sweating, peripheral cutaneous vasoconstriction, and brown fat metabolism
What is the maximum contact surface temperature?
48 degrees Celsius - this is a standard
Thermistor
- composed of metal oxide placed into a wire
Thermocouple
- an electric circuit with 2 metals. One remains at constant temp, other is exposed to area being measured
Liquid crystal
- consists of a flexible adhesive backing with plastic encased liquid crystals on a black backgroud
Infared
- Electronic instrument
What is the normal heat loss during anesthesia?
- 0.5 - 1 degree Celsius in the first 30 minutes
- Then, it can drop another 0.5 - 1 degree per hour after that
What are 3 temperature monitoring sites used?
- Pulmonary Artery
- Esophagus - probe should be located in lower 3rd or 4th of esophagus
- Nasopharynx
What are the methods of heat loss?
Radiation>Convention>Evaporation>Conduction
- 40% Radiation
- 30% Convection
Each 1 degree C decrease in temperature = _____________
metabolism decreases by 7%
What are s/s of Malignant Hyperthermia?
- Elevation of CO2
- Sympathetic hyperactivity
- Trismus (masseter muscle spasm)
- Whole body rigidity
- Cyanosis, unstable BP, dysrhythmias, hyperkalemia
