Cryotherapy Flashcards
1
Q
physiological effects of a local cold application =
A
Vasoconstriction
2
Q
Vasoconstriction =
A
magnitude of tissue cooling in the target tissue (not just the overlying skin)
reduced metabolic function
reduced motor and sensory nerve conduction velocities
3
Q
Vasoconstriction:
A
Cold application causes blood vessels to constrict, reducing blood flow to the area
This is the body’s attempt to preserve heat and protect the deeper tissues from the cold exposure
4
Q
Magnitude of Tissue Cooling:
A
The cooling effect reaches beyond the skin’s surface
While the skin temperature drops rapidly, the deeper tissues (like muscles and joints) cool more slowly
This is because subcutaneous fat provides insulation, which slows the rate of temperature change at deeper levels
5
Q
Reduced Metabolic Function:
A
Cold slows down the metabolic rate of tissues, which can reduce the demand for oxygen and decrease the inflammatory response
This is particularly useful in acute injuries to limit cellular damage and swelling
6
Q
Reduced Nerve Conduction Velocities:
A
The cooling effect of cold slows the conduction velocity of both motor and sensory nerves
This leads to reduced sensation and potentially a decrease in pain perception
The reduced motor nerve conduction can also temporarily decrease muscle spasticity and involuntary muscle contractions
7
Q
Vasoconstriction leads to a rapid decrease in skin temperature:
A
Subcutaneous temperature falls less rapidly and displays a smaller temperature change
8
Q
The ideal tissue temperature to achieve the optimal physiologic effects of cryotherapy is ___ per animal studies!!!
No conclusive recommendations for humans….
A
15 to 25°C (59-75 F)
9
Q
Human internal thermometer:
A
Preoptic region of anterior hypothalamus
10
Q
preoptic region of the anterior hypothalamus =
A
responsible for regulating temperature and triggering responses to cold or heat
Reflex activation of temperature receptors or stimulation of heat loss mechanisms triggered in part by the circulation of blood
through the preoptic region of the anterior hypothalamus
11
Q
When cold is applied, temperature receptors in the skin activate reflex responses =
A
stimulating mechanisms such as vasoconstriction and shivering to conserve heat, or facilitating heat loss when necessary
12
Q
heat abstraction =
A
fundamental principle behind cooling
Cold is not “added” to an object or tissue
heat is transferred away from the warmer material (the body) into the cooler material (ice pack, cold water, etc.)
All cooling occurs via heat leaving one material and going into another
Cold is never added to something to reduce
its temperature
13
Q
heat abstraction occurs through several mechanisms:
A
Conduction
Convection
Evaporation
Radiation
14
Q
Conduction =
A
the transfer of heat by direct
interaction of molecules (e.g., cold pack)
Direct contact between two materials of different temperatures (e.g., an ice pack on the skin)
Heat moves from the warmer body tissue to the cooler ice pack until thermal equilibrium is reached
15
Q
Factors Affecting Conduction in Cryotherapy:
A
Temperature Gradient
Type of Tissue
Length of Exposure
Tissue Depth
16
Q
Temperature Gradient –
A
the greater the difference between the body tissue and the cooling agent, the faster the heat transfer
17
Q
Type of Tissue –
A
Muscle and water-rich tissues cool faster than adipose (fat) tissue, which acts as an insulator and slows heat transfer
18
Q
Length of Exposure –
A
Longer exposure leads to deeper and more prolonged cooling, but excessive exposure can cause tissue damage
19
Q
Tissue Depth –
A
Surface tissues (like skin) cool more quickly, while deeper tissues require longer exposure to reach a therapeutic temperature
20
Q
Local Effects of Cryotherapy =
A
↓ blood flow due to vasoconstriction,
↓ nerve conduction velocity (NCV),
↓ tissue temperature
21
Q
↓ blood flow due to vasoconstriction =
A
Cold causes the blood vessels to constrict, reducing blood flow and helping to control inflammation and swelling
22
Q
↓ nerve conduction velocity (NCV) =
A
Cooling slows the transmission of nerve signals, reducing pain and muscle spasticity
23
Q
↓ tissue temperature =
A
Lower tissue temperatures reduce metabolic activity, which can limit secondary injury in acute trauma
24
Q
Cryotherapy is particularly useful in managing ________ making it a valuable tool in rehabilitation and sports medicine.
A
acute injuries
post-surgical recovery
muscle spasms
pain modulation
25
Convection =
heat abstraction by direct contact between the skin and moving fluid particles
Movement of a fluid (air or water) over the surface of the skin, enhancing heat loss (e.g., cold whirlpool or cold air exposure)
26
Unlike conduction, where heat transfer occurs through static contact, convection enhances heat exchange by:
continuously replacing warmed particles with cooler ones
27
Key Characteristics of Convection in Cryotherapy
Faster Heat Abstraction than Conduction
Practical Use for Distal Extremities
Dependent Position
28
Faster Heat Abstraction than Conduction –
Since the cooling medium (e.g., water) is constantly moving, it prevents the formation of an insulating layer of warm fluid around the skin, allowing for more efficient and consistent cooling compared to conduction (e.g., an ice pack).
29
Practical Use for Distal Extremities –
Cold whirlpools and contrast baths are most effective for areas like hands, feet, ankles, and wrists, where immersion is feasible.
30
Dependent Position –
The limb being treated is often in a dependent (gravity-dependent) position, which may lead to increased swelling in some cases, particularly in acute injuries where edema control is a concern.
31
Convection Clinical Applications
Cold whirlpools for post-exercise recovery (e.g., athletes reducing muscle soreness and inflammation)
Contrast baths (alternating warm and cold immersion) for vascular training and reducing stiffness
Cryoair therapy (cold air application) for large surface areas, such as after burns or in pain management
32
Cryotherapy for Posttraumatic Edema and Inflammation
For the first 24–48 hours after injury, cold therapy is the preferred modality
due to its ability to limit the acute inflammatory response and reduce secondary damage
33
Physiological Effects of Cold on Edema & Inflammation
Vasoconstriction → Reduced Fluid Filtration
Decreased Local Metabolism → Reduced Secondary Tissue Damage
Decreased Inflammation & Pain
34
Vasoconstriction → Reduced Fluid Filtration
Cold causes vasoconstriction of blood vessels, limiting capillary permeability and reducing the amount of fluid leaking into the interstitial space
This helps minimize swelling and edema formation
35
Decreased Local Metabolism → Reduced Secondary Tissue Damage
Cooling lowers metabolic demands, which is crucial because injured tissues are at risk of secondary hypoxic injury (cell death due to inadequate oxygen supply)
By slowing metabolism, cryotherapy reduces cellular energy requirements, preserving more viable tissue
36
Decreased Inflammation & Pain
Cold slows down pro-inflammatory enzyme activity and reduces nerve conduction velocity, leading to less pain perception
It also reduces histamine and prostaglandin production, further limiting inflammation
37
Cryotherapy for Posttraumatic Edema and Inflammation Clinical Application
Acute soft tissue injuries (sprains, strains, contusions)
Post-surgical recovery (to minimize swelling and pain)
Acute joint injuries (e.g., ankle sprains, knee injuries)
Immediately following fractures (if closed and stable)
38
Evaporation =
Heat loss due to moisture evaporating from the skin, such as when using vapocoolant sprays
Unlike conduction or convection, evaporation mainly affects superficial tissues and does not significantly lower deeper tissue temperatures
39
Vapocoolant Sprays
(e.g., Spray and Stretch, Instant Ice)
sprays contain volatile liquids that evaporate quickly, absorbing heat from the skin and causing a rapid cooling effect
40
Evaporation Clinical Uses:
Trigger Point Therapy – Used to help reduce localized muscle spasms and pain.
Facilitating Stretching – Often applied along tight muscles before stretching to reduce resistance and discomfort (e.g., hamstrings, upper traps).
41
Evaporation Physiological Effects:
↓ Skin Temperature = Provides a quick cooling sensation but has negligible effects on deeper tissues
↓ Motor Neuron Activity = can momentarily reduce muscle activity, helping with relaxation before stretching or manual therapy
42
Evaporation Limitations:
Short-lived effects – The cooling effect is brief and does not significantly impact deep tissues.
Not effective for swelling or inflammation – Unlike ice packs or cold immersion, vapocoolants do not reduce metabolic activity or tissue temperature at therapeutic levels.
43
Biophysical Principles of Tissue Cooling
several hemodynamic effects that influence blood flow and tissue metabolism
reducing inflammation, controlling edema, and managing pain after injury
44
Hemodynamic Effects of Cryotherapy
Reflex Vasoconstriction = Cold stimulates sympathetic nervous system activation, leading to a reflexive narrowing of blood vessels
↓ Blood Flow = Due to vasoconstriction, there is reduced circulation, which helps limit swelling and fluid accumulation
↑ Blood Viscosity = As blood cools, it becomes thicker (increased viscosity), increasing resistance to blood flow and further limiting circulation to the area
45
The Hunting Response (Cyclic Vasodilation & Vasoconstriction)
When tissue temperature drops below 10°C (50°F), a protective mechanism called the Hunting Response occurs
Periodic dilation of blood vessels may occur to prevent tissue damage from prolonged cold exposure
mechanism is more prominent in distal extremities (e.g., fingers, toes) where circulation is already limited
46
Cold therapy is best applied in ___ to prevent excessive vasoconstriction.
short intervals (10-20 min)
47
Neural Control of Blood Flow
The skin’s blood flow is controlled neurally by cold thermal receptors, which activate sympathetic vasoconstriction
This leads to localized vasoconstriction in the treated area
48
reflex vasoconstriction can also
result in a generalized cutaneous
vasoconstriction =
Cold exposure can trigger a reflexive vasoconstriction in other areas of the body, including the opposite (contralateral) extremity
This phenomenon occurs due to the systemic response of the autonomic nervous system, which works to conserve body heat
When skin temp is lowered, cold
thermal sensors in the skin are
stimulated, causing
vasoconstriction.
49
Key Effects of Cryotherapy on Post-Traumatic Edema & Inflammation:
↓ Fluid Filtration into Interstitial Space – Vasoconstriction limits capillary permeability, reducing fluid leakage into surrounding tissues
↓ Inflammation and Pain – Cooling slows down inflammatory processes and numbs nerve endings, providing pain relief
↓ Local Metabolism – Reduced cellular activity helps limit secondary tissue damage due to hypoxia
↓ Intramuscular Pressure – Lower pressure may reduce the risk of compartment syndrome, where excessive swelling compresses blood vessels and nerves.
50
Best Practices for Cryotherapy Application in Acute Injury:
Moderate Cooling is Ideal – Several hours or less at controlled temperatures provides benefits without excessive vasoconstriction
Avoid Prolonged or Intense Cold – Excessive cooling can cause a rebound increase in edema due to reactive vasodilation after extreme vasoconstriction
51
Combine Cryotherapy with ____
Compression & Elevation
Compression: Limits fluid accumulation in tissues
Elevation: Aids venous and lymphatic return, reducing swelling
52
4 Key Mechanisms of Cold-Induced Vasoconstriction
1. ↓ Histamine & Bradykinin (↓ Vasodilation)
2. ↑ Smooth Muscle Tone
3. Dorsal Root Ganglion Stimulation
4. ↑ Blood Viscosity
53
↓ Histamine & Bradykinin (↓ Vasodilation) =
Cold reduces the release of these vasodilatory chemicals, limiting blood vessel expansion.
54
↑ Smooth Muscle Tone =
Cold increases the contraction of vascular smooth muscles, promoting vasoconstriction.
55
Dorsal Root Ganglion Stimulation =
Cold stimulates sensory neurons, leading to reflex vasoconstriction via the sympathetic nervous system.
56
↑ Blood Viscosity =
Cooling increases thickness (viscosity) of blood, making circulation more resistant and further reducing blood flow.
57
effects of cold stimulus on local blood flow -> ____ ->
Vasoconstriction
↓ Blood Flow
Decreased circulation limits heat loss and reduces swelling in injured tissues
58
Peripheral Nerve Effects:
Decrease in Nerve Conduction Velocity:
Cooling can slow nerve conduction, which increases the pain threshold
This means the person might feel less pain or discomfort, as the nerves transmit signals slower.
59
Muscle Performance Effects:
Short Duration: If cooling is applied briefly, it typically has little to no impact on muscle performance or may result in a slight improvement in function.
Long Duration: Prolonged cooling can significantly decrease muscle performance
- Decreased Strength: The ability of muscles to generate force may be reduced.
- Decreased Proprioception: The sense of body position and movement may be impaired.
- Decreased Agility: The ability to make quick, controlled movements may be hindered.
60
Neuromuscular Effects:
Decrease in Spasticity: Cooling may help manage conditions involving spasticity (e.g., cerebral palsy, multiple sclerosis) by reducing excessive muscle tone or stiffness.
Management of Neurological Conditions: Cooling has therapeutic potential in some neurological conditions, such as reducing spasticity in conditions like multiple sclerosis or following a stroke
Facilitates alpha motor neuron activity and decreases gamma motor neuron firing
61
Nerve Conduction Velocity and Cooling:
Non-selective Cooling: When cold is applied, sensory nerves (responsible for detecting sensations like touch, pain, and temperature) cannot be cooled selectively
Both sensory and motor nerves are affected by cooling, leading to a general slowing of nerve conduction across all types of nerve fibers
Since cooling decreases nerve conduction velocity, this can impact the ability of motor nerves to transmit signals to muscles. This results in reduced muscle strength, coordination, and overall motor performance
62
Impact on Muscle Tension Generation:
Thermal agents, like cold, can reduce a muscle's ability to generate force or tension
This is because cooling slows down the neuromuscular system and affects the ability of muscles to contract efficiently
63
Duration of Exposure:
Short Exposure (3 minutes): A brief cold application might have minimal effects on muscle performance.
Longer Exposure (10 minutes): Prolonged cooling can significantly decrease muscle performance, impairing strength, coordination, and agility.
64
Cold for Pain Reduction:
Cold can be applied before exercise to reduce pain (by numbing the area), which can be helpful in conditions like muscle strains, post-exercise soreness, or joint inflammation
While cold may reduce pain, it can also impair muscle function. The muscle might not perform as well due to the effects of cold on muscle force generation. This could impact the effectiveness of an exercise session, particularly if strength or high-intensity activities are involved
65
Timing of Strength Assessments:
Since cold can alter muscle strength and force generation, strength assessments should ideally be done either before the application of cold or several hours after its use
This ensures that the strength measurements reflect the muscle's true performance without being influenced by the temporary effects of cold.
66
Patients with spasticity:
cold can temporarily decrease the amplitude of DTR and frequency of clonus
particularly useful in conditions like cerebral palsy, multiple sclerosis, and spinal cord injury
67
Spasticity reduction with cold may occur through at least two mechanisms:
1. A reflex decrease in gamma-motor neuron activity through stimulation of cutaneous afferents
2. A decrease in afferent spindle discharge by direct cooling of the muscle
68
Decrease in Gamma-Motor Neuron Activity:
Cold can suppress the activity of gamma motor neurons, which are responsible for maintaining muscle tone through the muscle spindle
By reducing their firing, cold can help decrease muscle stiffness and spasticity
69
Direct Cooling of Muscle:
Cooling the muscle itself can reduce the afferent spindle discharge, which is the signal sent from muscle spindles (sensors within the muscle) to the nervous system that contributes to the muscle's level of contraction
This results in a reduction in spasticity
70
Primary Goals with use of Cold Therapy
1. Limit edema formation
2. Reduce pain
3. Facilitate muscle relaxation
4. Limit secondary hypoxic tissue injury
71
Limit Edema Formation:
Cold therapy can help reduce swelling by constricting blood vessels (vasoconstriction), which decreases the flow of fluid to the affected area
This is particularly important in the acute phase of an injury, where minimizing edema can prevent further tissue damage and promote faster recovery
72
Reduce Pain:
Cold application works by numbing the area and reducing pain perception
It slows down the transmission of pain signals along nerve fibers, and the temporary decrease in nerve conduction velocity can increase the pain threshold, offering relief, especially in conditions like strains, sprains, or inflammation
73
Facilitate Muscle Relaxation:
Cold therapy helps to reduce muscle spasms and tension by decreasing the metabolic rate of the muscles, slowing down nerve activity, and reducing spasticity
This is beneficial in treating conditions like muscle cramps, spasticity, or post-exercise soreness
Cold can also reduce the frequency of clonus in patients with spasticity
74
Limit Secondary Hypoxic Tissue Injury:
Secondary hypoxic injury occurs when tissues do not get enough oxygen due to inflammation and swelling
By reducing blood flow and controlling edema, cold therapy can limit further tissue damage caused by this secondary injury
This is important in the early stages of injury or inflammation, helping to preserve tissue integrity and promote healing
75
Clinical Indications for Cold Therapy
Acute musculoskeletal trauma
Pain and muscle spasm
Myofascial pain syndrome/trigger points-
76
Acute Musculoskeletal Trauma:
Rest, ice, compression, and elevation (RICE): 20 to 30 minutes, several times/day
Over casts and bandages (longer duration)
commonly used for acute injuries such as sprains, strains, or contusions
helps manage swelling, pain, and inflammation in the early stages of healing
77
Pain and Muscle Spasm:
Delayed Onset Muscle Soreness (DOMS):
common after intense physical activity, especially when muscles are used in unfamiliar ways or overexerted
Cold therapy may provide temporary relief from the soreness by reducing inflammation and decreasing muscle activity
However, limited evidence from randomized controlled trials (RCTs) supports its effectiveness for DOMS, so its use may vary depending on individual response
78
Myofascial Pain Syndrome/Trigger Points:
particularly ice massage and vapocoolant spray
can help reduce muscle tension, alleviate pain, and release tight spots in the fascia or muscle fibers
79
Contraindications (Do Not Use Cryotherapy):
Cold Urticaria
Cold Intolerance
Paroxysmal Cold Hemoglobinuria
Cryoglobulinemia
Raynaud’s Phenomenon
Over a regenerating peripheral
nerve
Over an area of circulatory
compromise
Over an are of peripheral vascular
disease
80
Cold Urticaria:
An allergic reaction to cold that causes hives or a rash
Development of wheals characterized by
erythematous, raised borders and blanched
centers
Mast cells cause histamine to be released
81
Cold Intolerance:
Some individuals have an abnormal reaction to cold, such as extreme discomfort or physical distress, making cryotherapy unsuitable
82
Paroxysmal Cold Hemoglobinuria:
A condition where cold exposure causes the release of hemoglobin into the urine, which can be dangerous and should be avoided
Can follow local or general exposure to cold
Hemoglobin is released from lysed red blood cells and appears in urine
83
Cryoglobulinemia:
A condition where abnormal proteins in the blood precipitate at lower temperatures, which could cause severe complications when exposed to cold
presence of cryoglobulins (abnormal blood proteins) that form a gel when exposed to low temperatures (below body temp)
results in the aggregation of serum proteins = can lead to ischemia or gangrene
84
Raynaud’s Phenomenon:
A condition that causes vasospasm (narrowing of blood vessels) in response to cold, leading to reduced blood flow and potential tissue damage
Vasospastic disorder
Idiopathic or with other disorders (like SLE, thoracic outlet, trauma)
Smoking and caffeine can make it worse
Cycles of pallor, cyanosis, rubor, accompanied by numbness, tingling or burning
85
Over a Regenerating Peripheral Nerve:
Cold therapy can potentially interfere with nerve regeneration, so it should be avoided on areas where a nerve is healing.
86
Over an Area of Circulatory Compromise:
Avoid using cold therapy on areas with poor circulation (e.g., peripheral vascular disease) as it could exacerbate the issue and further restrict blood flow.
87
Over an Area of Peripheral Vascular Disease:
Cold can constrict blood vessels, worsening circulation issues in individuals with peripheral vascular disease, and may increase the risk of complications.
88
Precautions (Use with Caution Cryotherapy):
Hypertension
Over a Superficial Nerve
Thermoregulatory Disorders
Over an Open Wound
Over an Area with Poor Sensation
Impaired Cognition
In the Very Young or Very Old
People with Aversion to Cold
89
Hypertension:
Cryotherapy can cause a temporary increase in blood pressure, so it should be used cautiously in individuals with high blood pressure
cold can cause a transient increase in systolic and diastolic blood pressures
monitor patient when cryotherapy is used with hypertensive patients
90
Over a Superficial Nerve:
Cold application directly over a superficial nerve could result in nerve damage or discomfort due to altered nerve conduction.
91
Thermoregulatory Disorders:
People with impaired ability to regulate body temperature (such as those with certain neurological conditions) should be monitored closely while using cold therapy.
92
Over an Open Wound:
Applying cold over an open wound may impede circulation and slow healing, making it unsafe.
93
Over an Area with Poor Sensation:
Areas with impaired sensation (due to nerve damage or other factors) should not be exposed to cold, as the person may not feel discomfort or injury from excessive cold exposure.
94
Impaired Cognition:
Individuals with cognitive impairments (such as those with dementia) may not be able to properly communicate discomfort or recognize the risks of cryotherapy.
95
In the Very Young or Very Old:
Children and the elderly are more susceptible to extreme temperature changes and may not respond well to cold therapy
Monitoring is essential.
96
People with Aversion to Cold:
Individuals who have a psychological or physical aversion to cold should not be subjected to cryotherapy as it could cause stress or discomfort.
97
Methods of Providing Cryotherapy
Cold Packs or Ice Packs
Ice Massage
Vapocoolant Spray
Manual and Electric Cold Compression Units
Cold Baths
Cold Gels
98
Cold Packs or Ice Packs:
typically applied with a damp towel or thin fabric to prevent direct contact with the skin, which could cause frostbite
Duration: Apply for 20-30 minutes, ensuring it is intermittent if applied for longer periods.
Expected Outcomes: The patient will typically experience numbness and redness as the cold reduces blood flow and pain.
99
Ice Massage:
involves massaging ice directly on the skin, providing a more localized, intense cold application
Sensory Experience: Intense cold, burning, aching, analgesia
Area Covered: A 10 cm x 15 cm (4 in x 6 in) area can be covered in 5 to 10 minutes, depending on the intensity and the size of the area.
100
Vapocoolant Spray:
Vapocoolant sprays provide an instant cooling sensation when sprayed onto the skin
This is commonly used in trigger point release or myofascial pain management
Spray cools the skin rapidly and can have a pain-relieving effect when combined with gentle stretching
101
Manual and Electric Cold Compression Units:
combine cold therapy with compression, helping to reduce swelling while also providing the benefits of cold
can be applied to larger areas and are useful for post-surgical recovery or injuries with significant edema
Cold compression units are often applied intermittently or according to the manufacturer’s guidelines
102
Cold Baths:
involve submerging the affected body part (e.g., a hand or foot) in cold water, usually ranging from 50-59°F (10-15°C)
often used for large areas or whole-body cooling (e.g., contrast baths for swelling in limbs)
Expected Outcomes: Reduced muscle soreness and swelling, with a cooling effect over a larger surface area
103
Cold Gels:
provide a perceived cold sensation when applied to the skin
These gels often contain menthol or other cooling agents that create a temporary cooling effect
useful for mild pain relief and are often applied for conditions like muscle strains, soreness, or tension headaches
Expected Outcomes: Mild cooling and relief from pain
104
Tell the patient what to expect =
feel intense cold, followed by a burning sensation, then aching, and finally numbness
Telling them it will likely be uncomfortable and explaining, will help with putting them at ease and gaining trust
105
Caution with Flexible Gel Packs:
flexible gel packs stored in a standard freezer can reach a temperature of –17°C (–1°F), which is cold enough to potentially cause frostbite if applied directly to the skin
important to use a layer of damp toweling between the gel pack and the skin to create a barrier and reduce the risk of skin damage
106
Gel packs are less effective at cooling skin and deeper (intramuscular) tissues compared to ice packs or ice-water packs
because gel packs do not go through a phase change (from solid to liquid), meaning they do not absorb as much heat from the body
ess energy is required for heat transfer, which can make them less efficient at achieving deep cooling compared to ice-based options
107
Considerations
Select a cooling agent using clinical judgment
Consider indications, past medical history, area to be treated, adipose tissue,
contraindications, precautions, patient
preference, availability
Assess outcomes after treatment = Adverse reactions, patient response (pain, edema)
108
Main goals of Cold Therapy
Limit edema formation
Reduce pain
Facilitate muscle relaxation
