Thermal Agents: Cryotherapy

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 - 72-75 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 58F for analgesia
• Skin tempertaure must be reduced to 36F 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
  6.5 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 .2F of circulating blood
• Heart rate is decreased
• Respiration Decreases
• Shivering and increased muscle tone
• If core temperature continues to drop this is the
  bodys 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
• Raynauds Phenomenon

14
Raynauds 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
  wont 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
• Dont 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 bodys initial response
  to injury
• Rest limits scope of original injury by
  preventing further trauma
• Ice - function is to decrease cells 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
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 15-30 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
• 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
• 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
• 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
• Its use is based on tradition rather than fact

34
Cold Whirlpools

• Duration of Tx
• 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