Module 4 Flashcards
1st Law of Thermodynamics
law of conservation of energy (cannot be created or destroyed, only transferred)
0th Law of Thermodynamics
If A & B, and A & C are in thermal equilibrium (same temperature) then B & C will be in thermal equilibrium
2nd Law of Thermodynamics
Entropy (universal trend towards equilibrium) ex. Heat flows from high temp to low temp until equilibrium is reached
3rd Law of Thermodynamics
absolute zero (absence of all energy) = 0 K or -273.15 C or -460 F
Measurement of thermal state of object
Temperature
Energy that is transferred as a result of temperature difference, aka the measurement of the flow of energy
Heat
3 phases of thermoregulation
Afferent response –> central regulation –> efferent response
Conscious sensing of thermal state
Afferent responses
Involuntary responses of thermoregulation
Efferent responses
Inefficient efferent response that is absent in infants (up to 7yrs old)
Shivering
Shivering increases O2 consumption by up to ___%
400%
Normal difference between core and peripheral temperature
2-4 C
Efficient efferent response
Vasoconstriction
In infants, the process of non-shivering thermogenesis consist of beta receptors causing _____ to generate heat
lipolysis
Normothermia
37 C
Hypothermia
< 36 C
Hyperthermia
> 38 C
Monitor core temp with general anesthesia longer than ___ minutes
30 minutes
Maintain core temp of > _____
> 36 C
Heat released from body due to outside environment being cold
Radiation
Heat released from body due to airflow
Convection
Heat released from body due to contact with cold surfaces
Conduction
Heat released from body due to moisture on skin or airway
Evaporation
1st leading cause of heat loss in OR
Radiation
2nd leading cause of heat loss in OR
Convection
Responsible for 1/5th of heat loss in OR
Evaporation
OR atmospheric conditions leads to a drop of __ to __ degrees C/hr
0.5 - 1 C
Vasodilation related to anesthesia leads to a drop of __ to __ degrees C
1-2 C
MAC of volatile anesthetics are decrease by ___% per drop in degree C
5%
Maintain OR temp > ___ C to help maintain normothermia
23 C
3 ways to prevent hypothermia
- pre-op cutaneous warming
- airway heating/humidification
- warm IV fluids
- keep OR >23C
3 possible risks of hypothermia
- Increased O2 consumption
- Increased CV/MI events
- Increased sickling w/ sickle cell disease
- Impaired coagulation (platelet disfunction)
- Decreased drug metabolism
- Increased wound infection risks
- Reduced MAC of volatile anesthetics
What is the metric unit for work?
Joules
