Thermal Agents Flashcards
Define specific heat
The amount of energy required to raise the temperature of a given weight of a material by a given number of degrees
Define conduction and a few examples
Heat transfer resulting from energy exchange by direct collision between molecules at different temperatures
Examples: hot pack, cold pack, ice massage, contrast bath, paraffin bath
Define Convection and a few examples
Heat transfer through direct contact of a circulating medium with material of a different medium
Examples: whirlpool, fluidotherapy, cold packs that must be struck in order for the chemical reaction to occur
Define Conversion and a few examples
Heat transfer by conversion of a non-thermal form of energy (ex., mechanical, electrical or chemical) into heat
Examples: ultrasound, diathermy
Define Radiation and a few examples
Transfer of energy from one material to another without the need for direct contact or an intervening medium
Examples: infrared lamps, laser, UV lights
How do you calculate the rate of transfer by conduction?
= (area of contact) x (thermal conductivity) x (temperature difference) / tissue thickness
The greater the temperature difference between a heating/cooling agent and the body part it is applied to, the ____ the rate of head transfer.
faster
Materials with high thermal conductivity transfer heat _____ than those with lower thermal conductivity.
faster
The larger the area of contact between a thermal agent and the patient, the ____ the total heat transfer.
greater
The rate of temperature rise ______ in proportion to tissue thickness.
decreases
Is more heat transferred by convection or conduction over the same period of time?
Convection
How does blood circulating in the body transfer heat? Describe how…
Convection
Vasodilation increases the rate of circulation therefore increasing the rate at which the tissue temperature returns to normal
When it comes to conversion what does the rate of heat transfer depend on?
the power of the energy source
4 things that rate of tissue temperature increase depends on
1) The size of the area being treated
2) The size of the applicator
3) The efficiency of transmission from the applicator to the patient
4) The type of tissue being treated
Does conversion require direct contact between the thermal agent and the body?
No
What does the rate of radiation temperature increase depend on?
- The intensity of the radiation
- The relative size of the radiation source
- The relative size of the area being treated
- The relative size of the distance of the source from the treatment area
- The relative size of the angle of the radiation to the tissue
What are the 2 hemodynamic effects of cold?
- Vasoconstriction
- Cold-induced vasodilation
What are 5 neuromuscular effects of cold?
- Decreased nerve conduction velocity
- Increased pain threshold
- Altered muscle strength
- Decreased spasticity
- Facilitation of muscle contraction
Cold _____ metabolic rate.
decreases
Indications for cryotherapy
- Inflammation Control
- Edema Control
- Pain Control
- Modification of Spasticity
- Symptom Management in MS
- Facilitation of Motor Patterns
- Cryokinetics and Cryostretch
7 Contraindications of Cryotherapy
- Cold Hypersensitivity
- Cold Intolerance
- Cryoglobulinemia
- Paroxysmal Cold Hemoglobinuria
- Raynaud’s Disease and Phenomenon
- Regenerating peripheral nerves
- Circulatory compromise or PVD
What is cryoglobulinemia?
Aggregation of serum proteins in distal circulations that form a gel that car impair circulation