Thermal Agents: Cryotherapy

KIN 195

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:

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 H o t

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 tissue’s 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 energyExpressed 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 reduced to 58°F for analgesiaSkin temperature 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

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 drop 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 GENERAL THIS DOES NOT OCCUR WITH THERAPEUTIC ICE APPLICATION!

The Effects of Ice on Injury Response

Indications Acute injury or Inflammation Acute pain Small 1st degree burns Post-surgical pain and edema In conjunction with rehab ex. Neuralgia Acute or chronic muscle spasm Spasticity 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 Raynaud's phenomenon is a condition resulting from

poor circulation in the extremities (i.e., fingers and toes).  In a person with Raynaud's phenomenon, when his or her skin is exposed to cold or the person becomes emotionally upset, the blood vessels under the skin tighten and the blood flow slows

This happens because the blood vessels under the skin tighten.  When blood does not reach parts of the body, these areas may turn blue and feel cold.

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)

Metabolic Effects of ColdHypothesis: Decreases below 58 ° F cause a

“hunting” response (Lewis 1932) to occur Proposed mechanism: Histamine like release

increases vasodilatation as a self defense response

Knight & Draper, Chapter 13, beginning on p.220 examines the facts and fallacies of Cold-Induced Vasodilation, including:

CIVD doesn’t increase blood flow post cryotherapy Cryotherapy facilitates return to exercise & improves

progress (as well as decreasing pain & spasm)

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. Muscle contraction causes spindle contraction so it remains sensitive. The lower the temperature, the lower the spindle activity.

RICES: Rest, Ice, Compression, Elevation, Stabilization

RICES serves to counteract the body’s initial response to injuryRest limits scope of original injury by preventing further

trauma Ice can decrease cell’s metabolism, reducing 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.

RICES: Rest, Ice, Compression, Elevation, Stabilization, cont.

Compression - decreases the pressure gradient between blood

vessels and tissue and discourages further leakage from capillaries.

Also Encourages Lymphatic drainageCompression Types

Circumferential - provides even pressure Collateral - Pressure on 2 sides (aircast) Focal Compression - U-shaped horseshoe pads

RICES: Rest, Ice, Compression, Elevation, Stabilization, cont.

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

Stabilization Limits muscle spasm & neural inhibition related to

guarding the injured area Early stabilization eases the pain-spasm-pain cycle by

letting the muscles relax

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

“The purpose of cold applications post-immediate care is to facilitate pain-free exercise. Injury pain & muscle spasm are decreased, allowing exercise to begin earlier & progress faster” (Knight & Draper, p. 227)

Exercise is the key to rehab. Without proper ther ex, Cryotherapy will actually hinder rehab (p.228)

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)

Clinical Application

Cold Pack Ice Massage Ice Immersion Cryostretch Whirlpools

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

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 - 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

Subacute inflammation or injury

Muscle strain Contusion Acute or chronic pain

Contraindications All other ice contraindications When pressure is not

warranted Suspected Fx

Precuations 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 ice

Contraindications Acute injury where

gravity is contraindicated

Cryostretch

“Spray and Stretch” using vapocoolant Traditionally preformed with ethyl chloride

due to its ability to quickly evaporate and cool superficial tissue

This technique is used as a counterirritantsimply masks the symptoms to allow for a

stretch

Cryostretch

Precautions Can Cause frostbite Ethyl Chloride is

extremely flammable Ethyl Chloride is a

local anesthetics but if inhaled can become general

It’s use is based on tradition rather than fact

Contraindications Allergy Open wounds Post/surgical Eyes All other cold & passive

stretch contraindications Indications

Trigger points Muscle spasms Decreased ROM

Cold Whirlpools

Duration of Tx 15-20 minutes Temp 50° - 60 ° F

Indications Decrased ROM Cryokinetics Subacute to chronic

inflammation Peripheral nerve injuries

(avoid extremes)

Contraindications Acute conditions where

water turbulence would further irritate area

Gravity Postural Skin Conditions All other ice

contraindications

Cryotherapy take home points Immediate care needs 30+ min to prevent secondary

injury (ch. 12) Intermediate care needs 12-20 min to decrease pain

& facilitate ther ex (ch. 12) Cold-Induced Vasodilation is a myth (ch. 12) Ice is safer to the skin & it extracts more heat than

gel packs (ch. 5) The longer cold is applied, the slower tissue rewarms

(ch. 5) Elastic wraps compress better than flexi-wrap (ch. 5)

Cold Case Study, Due 2/22 Submit electronically on blackboard is preferred,

but paper OK at start of class 10 pts based on good use of sources, good

thought process, clear explanation of concepts As mentioned in assignment, site 3 primary

(journal) sources; secondary (textbook) sources do not count

Form for citation:Author last names First initials. Study Title. Journal Title,

year; volume: page numbers.