Thermal Agents Flashcards
Therapeutic application results in a transfer of heat to/from
- pt body
- btw tissues and fluids of body
heating agents transfer heat to
body
cooling agents transfer heat
away from body
what are local physiological reaction to thermal modalities
- localized sweating
- piloerection
- Changes in local metabolic rate, blood flow and skin conditions
What are Systemic physiological reaction to thermal modalities
- generalized sweating or shivering
- cardiovascular changes
thermal agents include?
- cryotherapy/ gel packs
- superficial heat
- deep heat
examples of superficial heat
- moist heat packs
- fluidotherapy
- hydrotherapy
- paraffin-wax bath
examples of deep heat
ultra sound
diathermy
Deep heat is also considered what?
mechanical/ electromagnetic
superficial thermal agents change temperature of what?
- skin
- superficial subcutaneous tissues
superficial heat
Heat that, when applied at a maximally safe clinical dosage, is only capable to raising the temperature of the skin and superficial tissues (up to 2 cm deep) to a thermally significant level.
superficial heat is dry or moist ?
both
deep heating agents increase temperature of deeper tissues like
- large muscles
- periarticular structures
deep heating agents heat up to depth of
5 cm
deep heat is in the form of
electromagnetic or magnetic energy
deep heat in the form of electromagnetic or magnetic energy is transmitted through
the skin and absorbed in deeper tissues (up to 5 cm) where it increases the kinetic action of molecules
what are the modes of heat transfer? (5)
- conduction
- convection
- conversion
- radiation
- evaporation
materials with higher specific heat?
- skin > fat or bone
- water > air
materials with a high specific heat requires more
energy to achieve the same temp increase than materials with low SH
Materials with high specific heat hold
more energy than materials with low SH at same temp
thermal agents with high SH are applied at what to transfer the same amount of heat
lower temp
what is conduction
an energy exchange by direct collision btw the molecules of two materials at diff temps
conduction requires what type of contact of the targeted area with the heating or cooling agent
direct contact
heat transfer by conduction occurs only btw materials of
different temps that are in direct contact with each other
safe and effective rate of heat transfer requires?
- Choosing materials with moderate thermal conductivity
- ensuring tolerable diff in temp
- using insulators to limit rate of heat transfer
guidelines for heat transfer by conduction are?
- the greater the temp diff btw heating/cooling agent and the body part it is applied to, faster the rate of heat transfer
- materials with high thermal conductivity transfer heat faster than materials with low conductivity
- the larger the area of contact btw a thermal agent and pt, the great the total heat transfer
- rate of temp rise decrease in proportion to thickness
how many layers of toweling should be used btw hot pack and pt to avoid burns
6-8
what should you remove before using conductive thermal agent?
jewelry
what is convection
heat transfer by direct contact between a circulating medium with another material of a different temp
convection transfer more heat than
conduction in the same time period