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Flashcards in thermal agents cold and heat Deck (27)
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1
Q

Modes of Heat Transfer

A
  • conduction
  • convection
  • conversion
  • radiation
  • evaporation
2
Q

Conduction

A
  • energy exchange through direct contact
3
Q

Rate of heat transfer=

A

area of contact x thermal conductivity x temperature difference= tissue thickness

4
Q

convection

A

heat transfer by direct contact of circulating medium and another material of different temperature

  • thermal agent is in motion
  • more efficient than conduction.
  • EX: whirlpool heats skin faster than if just immersed in a bowl of water of same temp
5
Q

examples of convection

A
  • fluidotherapy

- whirlpool

6
Q

conversion

A
  • heat transfer by conversion of non-thermal energy, such as mechanical , electrical or chemical energy, into heat. does not require direct contact of the agent and the patient

ex: US and diathermy
- heat transfer depends on the power of the energy source

7
Q

examples of conversion

A
  • US

- diathermy

8
Q

radiation

A
  • direct transfer of energy e/o need for contact or intervening medium. higher heat directed at lower heat area
  • infared lamp, laser, UV light
9
Q

evaporation

A
  • energy absorption because of conversion of material from liquid to vapor
  • vapocoolant spray
  • spray and stretch technique
  • sweating
10
Q

cooling is used to:

A
  • control inflammation, pain and edema
  • reduce spasticity
  • control symptoms of multiple sclerosis
  • facilitate movement
11
Q

cryotherapy Is most effective when

A
  • in the acute stage of healing

- can be continued into the reconditioning stage

12
Q

cryotherapy effects the body by influencing the following processes:

A
  • hemodynamic
  • neuromuscular
  • metabolic processes
13
Q

cryotherapy hemodynamic effects

-initial decrease in blood flow

A
  • vasoconstriction
  • <15-20 minutes duration
    • repeating ice applicstion after an initial 20 minute application for two repetitions of 10 minutes off the 10 minutes on lowers blood flow more than a single 20 minute application
14
Q

Hunting response

A
  • when cold is applied longer or when tissue temperature is below 10 deg C cold induced vasodilation occurs
  • indistal extremities exposed to cold more than 15 minutes there is a resultant in “hunting response”
  • maintained vasodilation is seen in forearms at 1 deg C for 15 mintues
15
Q

cryotherapy neuromuscular effects

A
  • decreaseing nerve conduction velocity
  • elevating the pain threshold
  • altering muscle strength
  • decreasing spasticity
  • facilitating muscle contrcation
16
Q

5 minutes cooling

A
  • decreases nerve conduction velocity

- fully reverses within 15 minutes in normals

17
Q

greater than 20 minutes of cooling

A
  • reversal takes >30 minutes

- cold reduces conduction of both sensory and motor fibers. especially A-delta pain fibers

18
Q

cryotherapy to decrease spasticity

A
  • apply cold for up to 30 minutes on a hypertonic region
  • effects can last 1-1.5 hours
  • BRIEF ~5 minutes can cause decr in DTR
  • 10-30 minutes decrease clonus
19
Q

cryotherapy inflammation control

A
  • less than 15 minutes for distal extremities
  • up to 30 minutes for larger regions
  • used in acute inflammatory phase
20
Q

cryotherapy for pain control

A
  • 10-15 minutes of cold, gives pain control for 1+ hours

- pain control due to: a-delta fiber blocking, gate control theory, reduced muscle spasm

21
Q

cryokinetics

A

combines cold an exercise to treat pathology
- apply cold to the point of numbness to decr pain then allow exercise to regain ROM

  • 20 minutes of cold then 3-5 minutes of exercise
22
Q

cryostretch

A
  • application of a cooling agent before stretching

- purpose: reduce muscle spasm allowing greater ROM increase

23
Q

reasons for considering heat

A
  • promotion of relaxation
  • increased extensibility of collagen tissue and decr joint stiffness
  • pain relief
  • reduction of muscle spasm
  • increase blood flow
  • resolution of inflammatory infiltrates
  • prepare stiff joints/tight muslces for exercise
24
Q

heat effects tissue via:

A
  • hemodynamic
  • neuromuscular effects
  • metabolic effects
  • altered tissue extensibility
25
Q

changes in muscle strength

A
  • strength and endurance decreases during the initial 30 minutes after application of deep or superficial heating agents
  • beyond 30 minutes and for up to 2 hours there is a gradual return in strength to rpior level, then an increase to above pretreatment strength levels
26
Q

best practice for maximum increase of length is:

A
  • tissue temp maintained at 41-45 deg C for 5-10 minutes
27
Q

burns cell death temp

A
  • cell dath above 45 deg C