Chapter 5- Thermal Modalities

Question 0

Law of Grotthus-Draper

Answer 0

1. If energy is not absorbed
   
   • it must be transmitted (to deeper tissues)
2. The greater amount absorbed
   - less transmitted
   - less penetration

Question 1

Heat exchange

Answer 1

Conduction-ice bags
Convection-whirlpool
Radiation-laser, UV light, diathermy
Conversion-Ultrasound, diathermy
Evaporation-vapocoolant spray

Question 2

Indications for Cryotherapy

Answer 2

• acute injury or inflammation
• acute/chronic pain
• acute/chronic muscle spasm
• ROM
• post surgical pain & edema
• in conjunction with exercise
• spasticity secondary to CNS disorders
• neuralgia

Question 3

Contraindications for Cryotherapy

Answer 3

• circulatory compromise/insufficiency
• uncovered open wounds
• cardiac respiratory involvement
• cold allergy
• anesthetic skin
• advanced diabetes (neurological deficit)
• PVD, Raynaud’s, Lupus

Question 4

Physiological effects of cryotherapy

Answer 4

• vasoconstriction
• decreased local metabolism
• decreased production of cellular wastes
• decreased pain
• decreased venous & lymphatic flow
• decreased NCV
• decreased muscle excitability (spasm & force)
• decreased inflammation

Question 5

Systemic Effects of cryotherapy

Answer 5

• general vasoconstriction
  
  • response from the hypothalamus
• decreased HR
• decreased RR
• shivering
• increased muscle tone

Question 6

Impact on Injury Response

Answer 6

• change in cellular function
  
  • decreased metabolism=decr edema formation
• change in hemodynamics
• change in lymphatic response
• change in neurological response
• change in muscle function

Question 7

Sensations of cryotherapy

Answer 7

1. Cold
2. Burning
3. Aching
4. Analgesia

Question 8

Temperature benchmarks

Answer 8

• 0-13 mins= steady decr. temp
• >13 mins= small fluctuations
• skin around 57 degrees- max decr. in local BF
• skin less than/equal to 59 degrees- lymphatic system response
• skin change -9 degree- muscle spindle sensitivity
• skin change -12 degree
- decr motor NCV (-14%)
- decr sensory NCV (-33%)
• skin around 58 degree- max analgesia

Question 9

Thermotherapy

Answer 9

• superficial less than/ equal to 2 cm
      - infrared lamps
      - MHP
      - paraffin bath
      - immersion
      - warm whirlpool 
• deep > 2 cm
      - ultrasound
      - microwave diathermy 
      - shortwave diathermy

Question 10

Indications for Thermotherapy

Answer 10

• subacute/chronic 
      - inflammation
      - chronic pain
      - muscle spasm
• decreased ROM
• hematoma resolution
• joint contractures

Question 11

Indications for Heat Application

Answer 11

• subacute & chronic inflammation

  - to encourage tissue healing
  - to reduce edema & ecchymosis
  - to improve ROM
  - to promote purulent drainage

Question 12

Contraindications for Thermotherapy

Answer 12

• acute injury
• circulatory compromise
• advanced arthritis
• thermoregulatory deficit
• anesthetic areas
• neoplasms
• thrombophlebitis

Question 13

Physiological Effects of Heat

Answer 13

• vasodilation
• increased: 
     - cell metabolism 
     - leukocyte delivery
     - capillary permeability 
     - venous & lymphatic drainage 
     - elasticity-collagen based tissues
     - NCV
• decreased:
      - muscle tone
      - muscle spasm
      - pain
• edema formation
• waste removal
• analgesia

Question 14

Systemic Effects of Heat

Answer 14

• increased: 
     - body temp
     - pulse rate
     - RR
• decreased:
     - BP

Question 15

Impact on Injury Response

Answer 15

• cellular function
      - metabolism= edema formation 
• change in hemodynamics
• change in lymphatic response 
• change in neurological response
• change in muscle function

Question 16

Temperature Benchmarks (Heat)

Answer 16

• 5-6 mins= rapid heat exchange
• 7-9 mins= heat exchange equalizes; possibly decreases
• 20 mins= max vasodilation
-106 degree= increase oxygen
- 102 degree= incr enzyme activity
• 104-113 degrees= incr tissue plasticity
• 113 degree= necrosis, protein lysis
• capsular shrinkage= 140-158 degrees