1. Thermal Agents: Cryotherapy

2. Basics of Heat
Heat: a term used to describe the energy that matter can store in the form of electronic, atomic, or molecular motion.
The great the molecular motion, the greater the heat production

3. Basics of Cold
Cold: in a physical sense is a negative condition, depending on the decrease in the amount of molecular vibration that constitutes heat. The less the molecular motion, the less heat production. Thus, a sensation of cold results.

4. Temperature:
Temperature is a measure of the average amount kinetic energy possessed by an individual molecule of a body (kinetic theory of heat).
Temperature is a measure of sensible heat of cold in a body.
Temperature is expressed as Fahrenheit or Centigrade.

5. Classification of temperatures: for treatment purposes, are classified as follows:

6. Transfer of energy: heat, or the loss of hear, occurs in any of the following ways:
Conduction: Contact
Convection: movement
Evaporation: through liquid-gas transfer
Radiation: electromagnetic waves
Conversion: transfer from one energy type to another

7. Factors in heat transfer Cont
Conductivity: the power of transmitting heat, electricity or sound. A tissues conductivity is usually dependent on the water content; the higher the water content the better the conductivity
Muscle % water and conducts well
Bone and skin are 5-16% water and poor conductors

8. Factors in heat transfer Cont
Resistance: the tissues opposition to the passage of energy
Expressed in Ohms.
Bone and fat have high resistance
Muscle and Skin low

9. Cryotherapy
Used to describe the application of cold modalities that have a temperature range between 32° and 65° F

10. Cryotherapeutic Benefits
To obtain therapeutic benefits
skin temp. must be reduced to 57 °F for optimal decrease in local blood flow
skin temp must be reduce to 58°F for analgesia
Skin tempertaure must be reduced to 36°F to produce intra-articular temp. changes in the knee
The temp of the skin over a joint decreased the temp in a joint proportionally 10° F skin ° F joint
Also remember that temperature is relative!

11. Effects of Cold on Application Site
Vasoconstriction
Decreased Rate of Cell metabolism resulting in a decreased need for oxygen
Decreased production of cellular wastes
Reduction of inflammation
Decreased Pain
Decreased Muscle Spasm

12. Systemic Effects of Cold Exposure
General vasoconstriction in response to cooling of the posterior hypothalamus (this happens with a .2°F of circulating blood
Heart rate is decreased
Respiration Decreases
Shivering and increased muscle tone
If core temperature continues to drop this is the body’s response to increase heat
IN GENERSAL THIS DOES NOT OCCUR WITH ICE APPLICATION!

13. The Effects of Ice on Injury Response
Indications
Acute injury or Inflam
Acute or chronic pain
Small 1st degree burns
Postsurgical pain and edema
In conjunction with rehab ex.
Neuralgia
Acute or chronic muscle spasm
Spastically accompanying CNS disorders
Contraindications
Cardiac or Resp. involvement
Uncovered open wounds
Circ. Insufficiency
Cold Allergy
Anesthetic Skin
Advanced Diabetes
Raynaud’s Phenomenon

14. Raynaud’s Phenomenon
A vascular reaction to cold application or stress that results in a white, red, or blue discoloration of the extremities. The fingers and toes are the first to be affected. This is a sympathetic nervous system reflex

15. Physiological Effects of Cold: Metabolic
Decreased secondary cell deaths by hypoxia (swelling prevents oxygen from reaching cells). The decrease in metabolism allows them to live without as much oxygen.
Normal body temperature is 37 ° C.
Increase above 45° C (113° F) proteins denature

16. Physiological Effects of Cold: Metabolic
Reduction of edema through decreased capillary hydrostatic pressure and decreased permeability and osmotic pressure
Increase blood viscosity (make it thicker so it won’t flood the area as quickly)
Decrease in chemical mediator effectiveness (they cause vasodilatation)

17. Physiological Effects of Cold: Metabolic
Decreases below 15 ° C (58 Þ F) a “hunting” response (Lewis 1932) incurs
Histamine like release yields an increase vasodilatation as a self defense response
Arterio-venal anastomoses (artery directly to veins) allow pooling of blood in feet, hands, ears, and lips. May be place of hunting response
Don’t go below 58 ° F and keep time shorter than 30 minutes to be on the safe side

18. Physiological Effects of Cold: Pain
Local decrease in free nerve ending sensitivity
Increases the threshold for nerve firing
Slows synaptic activity
Allows disruption of pain-spasm-pain cycle via analgesia

19. Physiological effects of cold: Hemodynamic
Vasoconstriction from smooth muscle in arterioles
reflex vasoconstriction from A-delta (spinal reflex to preserve body heat)
Cold blood hits hypothalamus and may start shivering response if cold enough
A small amount of vasoconstriction gives a 4 fold decrease in blood flow

20. Muscle Activity
Decreased muscle spasm by decreasing muscle spindle activity.
Intramuscular fibers (muscle spindle) runs parallel to fibers of the muscle. Ia and II run to dorsal horn of spinal cord and respond to stretch. As the muscle contracts the spindle contracts so it remains sensitive. Cold directly decreases the activity in the Ia and II fibers. The lower the temperature, the lower the activity.

21. Effects of Immediate Treatment
RICE - Rest, Ice, Compression, Elevation
Serves to counteract the body’s initial response to injury
Rest limits scope of original injury by preventing further trauma
Ice - function is to decrease cell’s metabolism, decrease the need or oxygen and reduce the amount of secondary hypoxic injury by enabling tissues to live on limited oxygen and secondarily reduce pain
Crushed ice is the ideal form of cold application during initial injury because it produces the most rapid temp. decrease.

22. Effects of Ice on Immediate Tx
Compression -
decreases the pressure gradient between blood vessels and tissue and discourages further leakage from capillaries.
Also Encourages Lymphatic drainage
Compression Types
Circumferential - provides even pressure
Collateral - Pressure on 2 sides (aircast)
Focal Compression - U-shaped horseshoe pads

23. Effects of Ice on Immediate Tx
Elevation
Decreases the hydrostatic pressure within the capillary beds to encourage absorption of edema by lymphatic system
This has the greatest effect at 90° perpendicular to the ground
at 45 ° the effect of gravity is 71% comparatively

24. Cryokinetics The use of cold in conjunction with movement
Used to decrease pain and allow for free motion through the normal ROM
Results in more pronounced macrophage reaction, quicker hematoma resolution, increased vascular growth, faster regeneration of muscle and scar tissue
Initiated when the underlying soft tissue and bone are intact and the pain is limiting the amount of function

25. Penetration depends on many factors:
Cold has a longer wavelength than heat
Local temperature gradient
Treatment surface area covered
thickness and characteristics of tissue treated (fat is an insulator, tissues with high water content have better heat transfer)

26. Slides in Packet for specific review of each Clinical Application
Cold Pack
Ice Massage
Ice Immersion
Cryostretch
Whirlpools
Slides in Packet for specific review of each Clinical Application

27. Cold Packs Ice Bags, Reusable Cold Pack Instant Cold Back
Tx time for all are minutes
Because of lasting effects application should be no less than 2 hours apart
For controlled Cold Therapy Units - may be applied continuously for 24 to 48 hours post acute injury or surgery

28. Cold Packs Precautions Indications
AC joint and other areas may not be suitable for wet wrap
Tension of elastic wrap should be enough to provide adequate compression without unwarranted pressure
Ensure Circulation w/wrap
Frostbite - if had before chance for reoccurrence
over large or superficial nerves
Indications
Acute injury (may use with wet wrap)
Acute or Chronic Pain
Postsurgical Pain and Edema
Shape of Body part

29. Ice Massage
Appropriate for delivering cold tx to small evenly shaped areas.
Most effective for muscle spasm, contusion and other minor well-localized areas
Duration of tx
5-15 minutes or until ice runs out
if the purpose is analgesic, then stop when numb

30. Ice Massage Indications Precautions Contraindications
Subacute inflam or inj
Muscle strain
Contusion
Acute or chronic pain
Contraindications
All other ice contraind.
When pressure is not warranted
Suspected Fx
Precautions
Injuries where pressure massage may be contraindicated

31. Ice Immersion Temp. 50° - 60 ° F Time 10-20 min. Indications
Acute Injury or Inflam.
Acute or Chronic Pain
Post surgical pain
Contraindications
Same as general Contraindications
Acute injury where gravity is contraindicated

32. Cryostretch “Spray and Stretch” vapocoolant
Traditionally preformed with ethyl chloride due to its ability to quickly evaporate and cool superficial tissue
This technique is limited to a counterirritant
simply masks the symptoms to allow for a stretch

33. Cryostretch Contraindications Precautions Indications Allergy
Open wounds
Post/surgical
Eyes
All other cold contraind & contraind to passive stretch
Indications
Trigger points
Muscle spasms
Decreased ROM
Precautions
Can cause frostbite
Ethyl Chloride is extremely flammable
Ethyl Chloride is a local anesthetic but if inhaled can become general
It’s use is based on tradition rather than fact

34. Cold Whirlpools Duration of Tx Indications Contraindications
15-20 minutes
Temp 50° - 60 ° F
Indications
Decreased ROM
Cryokinetics
Subacute to chronic inflammation
Peripheral nerve injuries (avoid extremes)
Contraindications
Acute conditions where water turbulence would further irritate area
Gravity
Postsutural
Skin Conditions
All other contraindications