Cryotherapy Flashcards
Cooling
removing or abstracting heat
3 ways in which cooling occurs
conduction
convection
evaporation
Conduction
heat abstraction by direct interaction (contact) of the molecules in the warmer area with those in the cooler area
rapid moving particles (heat) transfer to slower moving particles (cold)
Key feature of conduction
body comes in direct contact with the cooling agent, which is stationary
Most common conductive method of cooling
ice or cold packs
ice massage
Equation that summarizes the rate of heat transfer via conduction
D = Area × k × (T1 – T2)/thickness of tissue
D = rate of heat loss area = area being cooled k = thermal conductivity of tissues T = temperature
The greater the temperature difference between the skin and the cooling agent…
the greater the tissue temperature will change
What factors impact the effect of the cooling agent?
temperature difference between the skin and the cooling agent
type of tissue and tissue depth
length of exposure
activity level
ability of the cooling agent to maintain temperature
total surface area being cooled
type and size of the cooling agent
The efficiency of a material or tissue to conduct heat
thermal conductivity
What are the immediate local effects of cold?
decreased blood flow, tissue temperature and nerve conduction velocity
vasoconstriction
Does heat or cold take longer to return to its original temperature?
cold
What is the difference between arterial and venous blood? How do arteries and veins interact?
arterial blood coming from the body core is warmer than the venous blood returning from the periphery
normally, as warm blood flows toward the periphery, it passes by the cooler blood in veins that lie right next to the arteries (arteries and veins course through the body next to each other, but blood runs in opposite directions)
there is a countercurrent heat exchange between the warmer arterial blood and the cooler venous blood
What is the difference in applying cold/heat to a muscular patient vs an obese patient?
muscular patient has little adipose tissue and more muscle, making it easier to cause a temperature change
obese patient has a lot of adipose tissue and little muscle, making it harder to cause a temperature change
Vasodilated artery
heat has been applied and is carrying warm blood
once heat is removed, the vasodilation allows cooler blood to rush into the area, carrying away the heat due to decreased heat exchange and the arteries constrict
Vasoconstricted artery
cold has been applied and is carrying cold blood
once cold is removed, the vasoconstricted arteries will slowly dilate as heat exchange slowly increases
What is the relationship between tissue depth and the duration of cold application?
deeper tissues require longer duration of cold application to lower the temperature
skin –> subcutaneous tissue (fat) –> muscle
Convection
heat abstraction by direct contact between the skin and moving fluid particles
rapid moving particles (heat) transfer to slower moving particles (cold)
Most common convective method of cooling
whirlpools
Does heat abstraction occur at a faster rate with convection or conduction given the same medium and same starting temperature? Why?
convection
new (cooler) molecules are continually introduced to the skin surface when movement is occurring
when no motion occurs, molecules remain in contact with the skin surface and are warmed via conduction
when a body part is immersed in stationary cold water, the molecules in contact with the skin begin to warm and form a shield around the immersed limb
When is the only instance in which convection methods are cooling are practical?
for distal extremities
Key feature of convection
body comes in direct contact with the cooling agent, which is in motion
(initial = conduction, motion starts = convection)
Evaporation
transition from a liquid state of matter to a gaseous state of matter
Most common evaporative method of cooling
vapocoolant sprays
When are vapocoolant sprays used?
for temporary pain relief before stretching muscles with active trigger points or muscles with local spasm
When is cold used?
in the management of acute trauma
Why is cold used in the acute stages of injury?
arteriolar vasoconstriction reduces bleeding
decrease in metabolism and vasoactive agents (histamine and kinins) reduces inflammation and outward fluid filtration
pain threshold is elevated, decreasing pain
possible: reduction in muscle spasm
What is the immediate response of the blood to cold?
vasoconstriction (cutaneous reflex) of the arteries due to an increase of tone/contraction in smooth muscle, causing decreased blood flow
Why is cold used in acute trauma?
to decrease bleeding
What is the immediate response of the blood to heat?
vasodilation (cutaneous reflex) of the arteries due to an decrease of tone/contraction in smooth muscle, causing increased blood flow
What are the effects of evaporation on tissues?
very minor decrease in skin temperature
decrease in motor neuron activity
negligible effects on deeper tissues
What happens to neurotransmitters and metabolites when cold is applied?
vasodilating neurotransmitters and metabolites are reduced
What happens to neurotransmitters and metabolites when heat is applied?
vasoconstricting neurotransmitters and metabolites are reduced
What is viscosity? What affect does it have on blood flow?
resistance to blood flow
increased = more resistant to flow
decreased = less resistant to flow
What happens to the viscosity of blood flow when cold is applied?
increased blood viscosity = more resistance to flow
What happens to the viscosity of blood flow when heat is applied?
decreased blood viscosity = less resistance to flow
Why is cold the modality of choice in the first 24-48 hours following an injury?
decreases the movement of fluid into the interstitial space due to vasoconstriction (reduces edema)
decrease in metabolism and vasoactive agents (decreases inflammation and microvascular permeability)
decrease in pain due to increased pain threshold
How is post-traumatic edema controlled by cold in the first 24-48 hours following an injury?
decrease in fluid filtration into the interstitial space
What happens to inflammation, pain and metabolism when applying cold 24-48 hours after an injury?
all decrease
What happens to intramuscular pressure in the first 24-48 hours after injury when applying cold?
decreases
What type of cooling is best 24-48 hours after an injury?
moderate cooling
What should cooling be combined with 24-48 hours after an injury?
compression and elevation
When is the dependent position appropriate? When is it inappropriate?
not ideal for acute injuries, but more appropriate in the later stages of healing
Why effect does cold have on peripheral nerves?
lowers nerve conduction velocity, therefore increasing pain threshold (synapses are impeded or blocked, leading to challenges with depolarization), decreasing patient’s pain to help them move better
changes in the nerve might be a mechanism for decreasing pain
What effect does cold for a short duration have on muscle performance?
no effect or a slight increase in muscle performance
What effect does cold for a long duration have on muscle performance?
significant decrease in muscle performance due to decreased strength, proprioception and agility
What effect does cold have on the neuromuscular system?
decreases spasticity (only temporary)
helps with the management of some neurological conditions
Spasticity reduction with cold may occur through at least two mechanisms. What are these mechanisms?
decrease in gamma motor neuron activity through the stimulation of cutaneous afferents
decrease in afferent spindle discharge by direct cooling of the muscle
Cold has been used to decrease spasticity prior to performing what activities?
motor control activities
What does the amount of nerve conduction velocity decrease caused by cold application depend on?
the length of exposure to cold and the amount of cold
What effect does prolonged or extreme cold, such as frostbite, have on nerve conduction?
nerve conduction can be blocked due to possible nerve damage
What effect does cold for a short duration have on muscle strength?
may increase muscle strength
What effect does cold for a long duration have on muscle strength?
may decrease muscle strength
What testing should we avoid after cold application and why?
MMT because the effects of cold last for several hours and could result in an error in measurement
must be careful with activity, as there is a risk of injury due to decreased muscle strength
CONSIDER WHAT YOU WILL DO WITH PATIENTS AFTER APPLYING ICE
What effect does cold have on connective tissues?
increases the viscosity of connective tissues, leading to increased stiffness of connective tissues
Should you give ice to a patient with arthritis? Why or why not?
may increase complaint of joint stiffness because cold causes increased stiffness of connective tissue
When ice may not be appropriate in treatment?
if the main goal is stretching
When is cold the modality of choice?
the first 24-48 hours after an injury (in the acute phase following trauma)
What are the most common applications of cryotherapy?
after MSK trauma or for post-surgical (orthopedic) swelling and pain
Why is cold beneficial after MSK trauma and for swelling and pain after orthopedic surgery?
decreases edema, reduces pain, causes muscle relaxation and decreases the pain-spasm-pain cycle
How is cold able to help patients have MSK trauma and surgery?
pain and muscle/spasm guarding: counterirritation, increased nociceptor threshold of excitation, decreased muscle activity and decrease in pain to allow for stretching or movement
What are the primary goals when using cold therapy?
limit edema
reduce pain
facilitate muscle relaxation
limit secondary hypoxic tissue injury
What are the clinical indications for cold therapy
acute MSK trauma
pain and muscle spasm
myofascial pain syndrome
How is acute musculoskeletal trauma managed?
PRICE: 20-30 minutes several times per day
PRICE
Protection Rest Immobilization Cold Elevation
What should you take into consideration when applying ice over casts and bandages?
cold might need to be kept on for a longer duration (especially fiberglass casts)
What effect does cold have on delayed onset muscle soreness (DOMS)?
might reduce DOMS
The sensory, motor, and autonomic symptoms caused by myofascial trigger points
myofascial pain syndrome
Trigger points
areas when pressed causes radiating pain
Why should caution be observed when cold is applied to an area of neural tissue or superficial nerves?
there is a high risk of nerve injury or damage, such as neurapraxia and axonotmesis
Neurapraxia
temporary nerve damage that feels like the affected area is “falling asleep”
removal of the cooling agent will help
What types of inflammatory conditions warrant the use of ice?
tendonitis, bursitis and tenosynovitis
What types of sprains warrant the use of ice?
acute muscle and ligament sprains
With what types of pain should ice be used?
acute or chronic pain
Why should ice be used with patients have have myofascial pain syndrome?
to treat trigger points
What must we consider prior to using cryotherapy?
accessibility and availability, the body part and its size of area and whether compression/elevation is required
What must we consider in a patient’s PMH before using cryotherapy?
the time since the injury and if they have hypersensitivities to cold
How long should you avoid excessive stresses to the area post-cold treatment? Why?
1-2+ hours
the analgesic effect of cold could give patients a false sense of security
What should you do if a patient has hypersentivities to cold?
discontinue the use of cold
What are the normal sensory changes that occur in response to cold?
cold –> burning –> arching –> numbness
What is the normal response of the skin when exposed to cold? Why?
hyperemia
oxygen not dissociate as freely from hemoglobin at lowered temperatures, therefore the blood passing through the venous system is highly oxygenated, giving a red color to the skin
Reactive hyperemia
redness of the skin due to the delivery of warm blood to the surface
In general, how long is cold applied to tissues? What is the expected response?
20-30 minutes, intermittent (some them use 10 minutes on and then 10 minutes off)
numbness and redness
Why should could be applied intermittently?
to avoid or reduce the occurrence of any adverse responses to nerves or blood vessels
For small areas, what cooling agent is recommended?
ice massage
If there is concern about edema in distal extremities, what cooling agent is recommended?
cold compression
When cooling around a joint or larger muscle mass, what cooling agent is recommended?
an ice pack secured with an elastic bandage or weighted to provide compression
When is cold ALWAYS the appropriate choice?
in the acute phase of injury
How do you know a patient is having a hypersensitivity to cold?
hives or wheals will appear on the skin
Should cold be applied over areas of nerve regeneration or compromised circulation?
NO
What are the precautions of using cold?
absent or decrease thermal sensation (could also be a contraindication) – over an area of poor sensation
thermoregulatory disorder
altered cardiorespiratory status (angina, HTN, CAD and transient changes in BP)
over a superficial nerve
individuals with poor cognition
over an open wound
in a very young or very old person
persons with aversions to cold
Cold can impede the healing process. What should be take precaution with?
putting ice over a healing wound
What are the contraindications of using cold?
compromised peripheral circulation (PVD)
over an area of circulatory compromise
cold sensitivity symptoms
over a regenerating peripheral nerve
Cold uticaria
local and systemic reactions –>
local: in response to local cold application, patients develop wheals characterized by red, raised borders and blanched centers that are warm to the touch ; mast cell deregulation causes histamine to be released into the area, causing increasing capillary permeability, leading to redness, swelling and wheal formation (hives or itching)
systemic: flushing of the face, sharp drop in BP, increase HR and syncope/lightheadedness
Cryoglobulinemia
disorder characterized by the presence of cryoglobulins, abnormal blood proteins that precipitate and form a gel when exposed to low temperatures
results in the aggregation of serum proteins, which can lead to ischemia or gangrene
associated with multiple myeloma and certain types of viral and bacterial infections, chronic liver disease, RA and SLE
Raynaud’s phenomenon
a vasospastic disorder that can be either idiopathic, from trauma, SLE or Berger’s disease
smoking and caffeine can also worsen the frequency and intensity of the symptoms
cycles of pallor, cyanosis, rubor, and normal color of the digits may be accompanied by numbness, tingling, or burning
attacks are precipitated by exposure to cold or by emotional stress
Paroxysmal cold hemoglobinuria
can occur following local or general exposure to cold
hemoglobin (found in RBCs) is released from lysed red cells and appears in the urine
How does tissue depth impact the length of cold application?
the deeper the tissue, the longer time it takes for the tissue to cool
What are ice packs typically composed of?
crushed or cubed ice and water
water can sometimes include alcohol, gel or chemicals
What is recommended for any agent that has the ability to reach temperatures below 30° F?
the use of a towel over the skin
wet the towel with lukewarm or room-temperature water to make it more comfortable for the patient and to promote thermal conduction (will transfer cold more efficiently than a dry towel)
What is the cost of using a towel with a cooling agent?
it will decrease the effectiveness of the cooling agent
When are ice packs used?
in combination with acute edema management
Why is ice the most effective type of cold?
it must undergo a phase change from solid to liquid, which causes greater heat extraction than when no phase change is required
Why is an ice pack safe to apply directly to the skin?
temperature of the ice pack upon contact with the skin is typically just under 32°F
Commercial gel packs
usually contain a silica gel and are available in a variety of sizes and shapes to contour to the area to be treated
How long and at what temperature should ice packs be stored prior to use?
should be stored at 23 degrees F for at least 2 hours before use
What is the purpose of using a towel related to hygiene?
for infection control purposes when reusing a cold pack
What often is used to secure an ice pack?
a strap
How long do ice packs last?
15-20 minutes
What is the benefit of adding alcohol to an ice pack? What does this mean?
the mixture can reach temperatures colder than just using ice
always use a towel with these ice packs
Ice packs activated by squeezing or hitting them
chemically activated by squeezing or hitting them against a hard surface
usually marketed for first aid and designed for one-time use only
NOT marketed for general use
Where and when is ice massage usually performed?
over a small treatment area (muscle belly, tendon, bursa over trigger points or before deep pressure massage)
What is used to perform ice massage? How is it applied
a cup or cube of ice
When are vapocoolant sprays used?
to treat trigger points (acts as a local anesthetic) and induce relaxation of tight muscles before stretching
How is vapocoolant used to treatment trigger points?
“Spray and Stretch” technique
the patient is positioned comfortably and the muscle containing the trigger point is placed on passive stretch
spraying is done in unidirectional sweeps along the muscle (proximal to distal) over the trigger point areas and over the areas of referred pain while maintaining and gently increasing the passive stretch (spray 12-18 inches away from the skin)
repeat spraying and rewarming
What is the downside of using vapocoolant spray?
very little to no actual cooling or decreased temperature
Cold compression devices
allow for manual circulation of cold water through a cuff that is applied over an extremity
sleeve provides come compression to treat edema
When are ice baths most practical?
when cooling distal extremities
When are ice baths NOT practical?
if the distal extremity needs to be elevated
What do ice baths ensure?
direct circumferential contact
What is the typical water temperature of an ice bath?
50-65 degrees F
What is the downside of using an ice bath?
can be uncomfortable and at the least tolerated
The lower the temperature range of the ice bath…
the shorter the duration of ice bath usage
Commercially available cold gels or creams
give the perceived sensation of cold (most of these gels use chemicals)
Whirlpool temperature guidelines
very cold: 34-55 degrees F
cold: 55-65 degrees F
cool: 65-80 degrees F
Contrast bath
alteration of hot and cold applications
Contrast bath temperatures
96-110 degrees F and 50-65 degrees F
Contrast bath ratios
3:1 or 4:1 Hot:Cold Ratio
When are contrast baths used?
for the control of edema (slight rise in temperature without additional accumulation of edema)
What is the problem with contrast baths?
produce little to no “pumping action” although this was the original premise
little research support, but used clinically
What is a good alternate to contrast baths? When can this be considered?
cryokinetics
if movement is allowed
Cryokinetics
technique that combines the application of cold with exercise
What is the goal of cryokinetics?
to numb the body part with cold application
once numb, have the patient perform the exercise (or WB) to treated the injured body part
can repeat with cold application, numbness and exercise
When should cryokinetics be avoided?
if immobilization (PRICE) is the goal during periods of acute injury
