Transcript Cryotherapy and Superficial Heat Modalities

Thermal Agents: Cryotherapy
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
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.
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.
Classification of temperatures:
for treatment purposes, are
classified as follows:
Hot
Very Cold
32 to 55 F
Cold
55 to 65 F
Cool
65 to 80 F
Neutral
80 to 92 F
Warm
92 to 98 F
Hot
98 to 104 F
Very Hot
104 
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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
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
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
Cryotherapy
• Used to describe the application of cold
modalities that have a temperature range
between 32° and 65° F
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
6.5° F joint
– Also remember that temperature is relative!
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
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!
The Effects of Ice on Injury
Response
• Indications
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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
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
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
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)
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
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
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
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.
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.
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
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
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
Penetration depends on many
factors:
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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)
Clinical Application
• Cold Pack
• Ice Massage
• Ice Immersion
• Cryostretch
• Whirlpools
• Slides in Packet for specific review of each
Clinical Application
Cold Packs
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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
Cold Packs
• Indications
– Acute injury (may use
with wet wrap)
– Acute or Chronic Pain
– Postsurgical Pain and
Edema
– Shape of Body part
• 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
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
Ice Massage
• Indications
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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
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
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
Cryostretch
• 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
• Contraindications
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Allergy
Open wounds
Post/surgical
Eyes
All other cold
contraind & contraind
to passive stretch
• Indications
– Trigger points
– Muscle spasms
– Decreased ROM
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