Ice is the Magic Medicine
CRYOTHERAPY
Cryotherapy is
the therapeutic use of locally applied coolants to affect various physiological
processes through the cooling of soft tissues.
Cooling occurs when heat is removed or lost from an object through
conduction of heat from one mass to another, or through evaporation.
Conduction occurs when heat is transferred from a warm body to a colder
body by direct contact between their surface molecules. The slow moving molecules of the cold body
speed up by absorbing energy from the faster moving molecules of the warm body,
thereby becoming warmer, while, conversely, the faster moving molecules of the
warm body slow down as they lose energy and become cooler. Conduction occurs
when a cool mass (like ice) is applied continuously to the skin, or when a body
part is immersed in cold water. As the
body or body part cools, the ice or cold water heats up.
 |
| Ice bag |
Cryotherapy has historically been used to
provide pain relief, reduce fever, slow the damage of thermal burns, control
bleeding, and prevent or reduce edema caused by soft tissue trauma. Cryotherapy has also been shown to be useful
for the reduction of extrafusal and intrafusal
muscle spasm, neuromuscular
hypertonicity, and spasticity. Cryotherapy
may additionally be used to elevate the pain threshold and slow destructive enzyme
action that occurs in some joint diseases.
 |
| Cold gel pack |
Methods of Cryotherapy
1) Cold packs
2) Ice massage (over a small area)
3) Cold baths (for an entire extremity)
4) Vapocoolant Spray
Physiology behind Ice therapy
The cooling of bodily tissue is governed by
two basic physiological principles:
(1) the cooling effect on the soft tissue by
an ice massage or ice pack will decrease as the depth of the tissue
increases; (2) the time required for
cooling to be effective will vary according to the type of tissue being cooled
(the speed of cooling underlying tissues will decrease as the amount of
insulating fat increases).
 |
| Ice bath of foot |
As cooling decreases tissue temperatures, the
sensory nerves in the skin are provoked to fire continuously until
physiologically exhausted. Usually this
causes the subject to predictably experience a sequence of sensations including
aching, burning, and finally numbness (though exceptions will be found). Numbness or temporary local anesthesia occurs
as the sensory nerves are exhausted and, coincidentally, when the normal erythema
of the skin reaches its zenith.
 |
| Vapocoolant spray |
Deeper nerves (below the epidermis) may also
be affected by cooling. Muscle cooling
has been shown to affect the afferent nerves arising from the muscle spindle flower-spray
and annulospiral sensory nerve endings.
Their rate of discharge decreases as the temperature of muscle tissue
decreases. As the temperature drops, the
sensitivity of the muscle spindle initially
increases (a minimal stretch is required for a spindle response at
30°C), but as the temperature decreases further, the spindle's sensitivity decreases
(requiring a bigger stretch to elicit a muscle spindle response). Some evidence has suggested that cooling may
affect a decrease in the rate of muscle spindle discharge by causing membrane
hyper polarization with a lowering of
potassium concentration. Cooling may also affect the speed of impulse of
the gamma efferents to the muscle spindle
by decreasing gamma biasing of the
muscle spindle intrafusal muscle
fiber,thereby depressing membrane activity and the stretch reflex. This occurs in the muscle after 10 minutes of
cooling with a crushed ice pack (if the muscle isn’t too deep).
.jpg) |
| Ice cube massage |
Cooling of the exteroceptors of the skin has
been shown to increase the amplitude of the H response (a phasic stretch reflex
induced by electrical stimulation), largely by- passing the muscle spindle, by
increasing or facilitating alpha motor neuron excitability.
As the temperature drops toward 5°C, there are
decreases in the amplitude and frequencies of the motor endplate potentials
combined with increases in their duration. If cooling is sufficient to drive
the muscle tissue temperature at the neuromuscular junction down to 5°C,
blockage of the junction has been shown to occur.
 |
| Cryotherapy unit |
The effects of cooling on peripheral nerves
are primarily dependent on myelination and fiber diameter. All nerve fibers are generally affected by cooling. The smaller medullated fibers are affected
first, then the large medullated, and finally the non-medullated. The smaller gamma efferent fibers are more
sensitive to cold (their frequency slowing more quickly and to a greater
extent) than are the alpha efferents.
Motor nerve conduction velocity decreases
linearly at a rate of between 1.84 and 2.4 meters per second per degree
(centigrade), as the temperature drops from 36 to 23°C. Proprioceptive sensory
fibers (and others important for motor learning) are relatively insensitive to
cooling since they are large diameter myelinated fibers.
.jpg) |
| Latest mobile cryotherapy unit |
Additionally, cooling has been shown to affect
the various vascular structures at all levels to the extent of causing an
initial reflex vasoconstriction to occur.
It is unclear what specifically causes vasoconstriction, but various
reasons have been suggested. One theory
is that vasoconstriction occurs in tissues in which the cold induces an
increase in the firing of sympathetic nerve fibers within the tissues cooled. Another theory postulates that
vasoconstriction occurs from the cooling of tissues by directly affecting the
blood vessels themselves.
Whatever the specific mechanism may be,
vasoconstriction has been shown to reduce blood flow in tissues cooled to 18°C. As cooling continues, however, and the tissue
temperature reaches 2°C, vasodilation occurs in a physiological attempt to increase blood flow and thereby prevent
tissue damage. This phenomenon is called the Lewis Hunting Reaction.
.jpg) |
| Hand immersed in ice |
Cryotherapy has been shown to be extremely
valuable when applied in combination with other modalities. Ice packing, for example, may be used
together with heat in the form of contrast packs to increase capillary bed
circulation and to reduce joint stiffness.
The hot pack should last for 10 minutes
followed by a three-minute ice pack.
The
heat should then be reapplied for four minutes followed by another three-minute
ice pack; this process should be repeated for a total treatment time of 30
minutes.
Research has demonstrated that the cooling of
a joint results in vasoconstriction and a decrease in interarticular
temperature. This has the effect of
slowing enzyme action and its destructive action. It has also been demonstrated
that cryotherapy applied over the area of an over-stretched ligament may
increase edematous swelling in the general area but decreases the edema around
the injured ligament.
 |
| Applying ice pack |
Cryotherapy has been shown to have a rather
dramatic effect on soft tissues because of the physiological responses it
provokes. As a result, it has become a
valuable tool for the treatment of various physical dysfunctions.
Precautions
Adverse effects of ice packing are rare, but
some of the symptoms that may be associated with abnormally high histamine
production triggered by cooling include cold urticaria, erythema, itching,
sweating, and shortness of breath. More
severe symptoms may develop including syncope,
tachycardia, extra systoles, dysphagia,
abdominal cramping or diarrhea.
These symptoms may occur during therapy or soon after, but they have
been known to appear several hours later.
 |
| Erythema |
Cold hemolysins and agglutinins produced in
abnormal amounts in response to tissue cooling may produce significant anemia,
malaise, chills, fever,
paroxysmal cold hemoglobinuria of the kidney, or the dermal symptoms of
cold urticaria or ulcerations.
Abnormally high cryoglobulin production in
response to cooling may produce chills and fever and may adversely affect
vision and hearing (blindness or deafness in the extreme). It may cause conjunctival hemorrhages and epistaxis, anemia with fibrinogenopenia, elevated
sedimentation rates, and abnormal numbers of cryoglobulin inclusion cells.
Other symptoms include itching, purpura, cold urticaria, ulcerations and necrosis, dyspnea,
stomatitis, melena, and bleeding of the gums.
 |
| Ice burn |
Cryotherapy may be contraindicated for open
wounds. The use of a cryotherapeutic application
should be based on the extent, nature, depth of the wound, and the chances of contamination. Advantages must be weighed against the
risks. For example, there is little risk
and a great deal of benefit to be gained by cooling a freshly contused area, in
spite of the presence of a shallow wound.
It may be helpful in slowing or stopping bleeding if a dry sterilized
ice bag is used or if the treatment site is protected from the touch of any
water (a plastic bag may be helpful).
However, cryotherapeutic applications may further damage involved
tissues if the wound is deep or the vasocirculation in the area is impaired
through application.
Contraindications
1) Cold urticaria
2)Cryoglobulinemia
3)Raynaud’s phenomenon
.jpg) |
| Raynaud’s phenomenon |
4)Paroxysmal cold hemoglobinuria
5)Peripheral vascular disease
.jpg)
Comments
Post a Comment