WK2- Cryo and Thermal Modalities Flashcards
Define cryotherapy.
The use of cold for therapeutic purposes
What are the principle ways of energy transfer for heating and cooling agents ?
Conduction: transfer of heat by direct contact
Convection: Heat transfer by direct contact with moving fluid or particles
Evaporation: Heat removed as a molecule when changing from liquid to gas.
True or False. Tissues with higher water content have better thermal conductivity than adipose tissue.
True
Classify the following in order of decreasing thermal conductivity: Air, Metal, Ice, Bone, Muscle, Fat, Water
Metal, Ice, Water, Bone, Muscle, Fat, Air
Which cryotherapy intervention is the most effective type of cold ?
Ice, due to its solid to liquid phase change which causes greater heat extraction.
What are the positive effects of cold on tissues ?
Decreases bleeding, reduces inflammation, elevates the pain threshold, Reduces skeletal muscle spasm
What are the negative effects of cold on tissues ?
Affects muscle performance: in the short term increases muscle performance, long term reduces it
Increases joint stiffness
Increases tissue viscosity and decreased elasticity
What are the hemodynamic effects of cryotherapy ?
decreased blood flow due to vasoconstriction with short duration cold ( 15 minutes or less )
if cold is left too long then may vasodilate vessel
Describe the effects of cold therapy on edema and inflammation.
effects microcirculation and metabolism, decreasing oxygen demand
decreases capillary dysfunction
decreases venule diameter
reduce accumulation of leukocytes
reduce intramuscular presure
What are the effects of cryotherapy on peripheral nerves ?
cold decreases conduction velocity and synaptic activity of peripheral nerves both sensory and motor. Raises pain tolerance, affects muscle performance.
In areas of superficial neural tissue, cold may cause neuropraxia, and axonotmesis
True or False. Cold therapy increases propioception.
false
What are the clinical indications for use of cryotherapy ?
Swelling, pain, Muscle spasm/hypertonicity, Tissue Injury
In acute MSK conditions what can accompany cryotherapy to control pain, inflammation and loss of function ?
compression
Describe the process in how cooling the skin can elevate the pain threshold and reduce pain.
cold stimulate thermal A-delta fibers and may override pain signals from C fibers
Increases threshold for depolarization
Slows nerve conduction velocity
Extreme cold can block nerve conduction
Is cold effective in diminishing DOMS ?
NO!
What are the normal sensations that you as a PT can educate your patients on when receiving cryotherapy ?
intense cold, burning, aching, numbness
For how long should a PT apply cryotherapy ?
20-30 minutes for conductive cooling generally
10 min on 10 min off x2
Repeated applications of cooling 30 min every 2 hours
Ice massage for 5-7 minutes
What are some different methods for cold therapy ?
frozen peas, ice massage, ice or cold pack, ice/cold bath, commerical cold pack or gel, cold compression units, vapocoolant sprray
For any agent that goes under _____ F a towel should be used.
30 F
For colder temperatures of an ice bath (longer/shorter) durations should be used.
shorter
True or False. Cold gels function the same as typical cooling agents.
False, they only provide the sensation of coldness
What are the contraindications to cold therapy ?
Cold Urticaria: Redness, swelling, wheals-raised areas of skin that are blanched; systemically; general swelling, flushing face, sharp drop in BP, increased HR, syncope
Cryoglobulinemia: abnormal blood proteins precipitate and form a gel when exposed to low temperatures; may result in ishemia or gangrene; found in those with multiple myeloma, certain viral and bacterial infections, SLE, other rheumatic diseases
Raynaud’s: cycles of pallor, cyanosis, rubor, and normal color digits with numbness, tingling, or burning
Paroxysmal Cold Hemoglobinuria: hemoglobin released from RBCs and appears in the urine
Poor circulatory areas
What are the common precautions to cold therapy ?
HTN: cold may cause increase in BP
Hypersensitivity, Impaired circulation, thermoregulatory disorder
Open Wounds
Superifical peripheral nerve areas
Psychological aversion to cold
What are the essentials when documenting cold treatment:
type of cold, duration, site of application including side, position of patient, use of concurrent compression or elevation, change in skin appearance, patient response, adverse response
What is the safe therapeutic range for thermal therapy ?
104-113 degrees F.
How deep will superficial heat modalities penetrate ?
1-3cm
What are the superficial heat modalities ?
Moist hot packs
Paraffin Wax
Fluidotherapy
Warm whirlpool
Air activated heat wraps
Electric heating pads
How deep will deep heat modalities penetrate ?
3-5cm
What are the deep heat modalities ?
US, diathermy
What is the metabolic reaction to heat ?
chemical reactions and metabolic activity increases, increased oxygen available for tissue repair
What are the vascular effects of heat ?
Vasodilation,
in the skin:
Heat applied to the skin stimulates cutaneous thermoreceptors. These sensory afferents carry impulses to the spinal cord. Some of these afferent impulses are carried through branches antidromically toward skin blood vessels, and a vasoactive mediator is released. This results in vasodilation through an axon reflex.A local spinal cord reflex is elicited through heat activated cutaneous afferent stimulation. This reflex results in a decrease in postganglionic sympathetic adrenergic nerve activity to the smooth muscles of blood vessels.
Heat therapy should be combined with _________ for maximal effects.
exercise
What are the neuromuscular effects of heat ?
Elevation of the pain threshold through the thermal gate theory: increased firing rate of thermoreceptors in the skin may block primary nociceptive afferents to the dorsal horn
Break the pain spasm pain cycle
alter nerve conduction velocity
change muscle spindle firing rate: decrease muscle spasm
True or False. Heat is more effective in the management of DOMs than cold.
True
What are the effects of heat on connective tissue ?
increased elasticity, muscle flexibility
decreased joint stiffness and viscosity
How long does it take for the heat to enact peak temperature change in the skin and subcutaneous tissue ?
6-8 minutes with adequate blood supply
How long is heat exposure required to reach muscle ?
15-30 minutes.
What are the conductive and convective heat modalities ?
moist hot packs, paraffin wax, electric heating pads, microwaveable heating packs, air acitivated heat wraps
convective: fluidotherapy
How many towel layers should be added to moist hot packs ?
6-8 towels for safety
How long should you apply moist hot packs for ?
10-30 minutes
What does the low specific heat of paraffin wax mean for patients ?
does not feel as hot as water at the same temperature.
Paraffin wax is proven useful in which patient population ?
those with RA
Up to how long can you wear an air activated heat wrap ?
8 hours
What are the clinical applications of heat therapy ?
reduce pain, reduce muscle spasm, reduce stiffnesss and improve ROM, improve tissue healing, 15-30 minute intervention time
What are the common contraindications and precautions to thermal therapy ?
areas lacking thermal sensation, areas of vascular insufficiency, hemorrhage, malignant cancer, acute inflammation, infection, over liniments or heat rubs, any situation deemed unreliable by practitioner.
What patient examination procedures should not be performed following cryotherapy?
MMT
True or False. Vapocoolant sprays are used to induce muscular relaxation to then stretch the muscle to improve muscle flexibility by providing a counterirritant stimulus to thermal afferents overlying the muscles.
True.
How does the application of heat to the body cause vasodilation of blood vessels remote from the application site?
axon reflex.
