cryotherapy & thermal agents - exam 1 Flashcards
what is conduction?
energy exchange by direct contact of stationary materials (tissues) at different temperatures
how is head conducted?
from the material at a higher temp to material at lower temp
– cold pack: heat transferred from patient’s skin to cold pack
– heat pack: heat transferred from hot pack to patient’s skin
what factors is rate of heat transfer dependent on?
area of contact
thermal conductivity
temperature difference
tissue thickness (decreases rate)
the greater the temp difference between two surfaces:
the faster the rate of heat transfer
what is a good use of materials to make sure you are creating a safe medium for heat transfer?
6-8 layers of towels between hot/cold pack and patient (trap air and have a low thermal conductivity to slow rate of heat transfer)
why should you remove metal from areas of contact?
metal has a high thermal conductivity
what is convection?
direct contact between circulating medium (not stationary) and another material of a different temp.
vector = moving
how would heat transfer occur more rapidly?
faster speed of movement between two materials (i.e. whirlpools vs immersion)
what is conversion?
converting a non-thermal form of energy into heat
does conversion require direct contact? if not, what does it require?
no
requires an intervening material to help transmit the certain type of energy (ultrasound gel or lotion)
regarding conversion, what does rate of transfer depend on?
the power of energy source not the temperature (US head does not need to be hot)
what form of energy is ultrasound?
mechanical form - can be “converted” to heat when sufficient intensity to a tissue absorbs the sound waves
what form of energy is diathermy?
electromagnetic form of energy - causes rotation of polar molecules, “converts” to heat when friction between the molecules increases tissue temp
what is specific heat?
amount of energy required to increase the temperature of a material by a “x” number of degrees (C)
tissues with high specific heat require ______ energy to heat and hold more energy compared to ______
more
materials with low specific heat
list the materials in order of heating up faster to heating up slower
air
bone
fat
average for human body
muscle
skin
water
what does a therapeutic use of cold do in rehab medicine?
control inflammation, pain and edema
reduce spasticity
control symptoms of MS
facilitate movement/ROM
what is abstraction?
removal of heat by means of conduction or evaporation
what ICF domain is cryotherapy categorized into?
basic structures and function
what are the hemodynamic effects of cryotherapy?
- vasoconstriction (10-15 minutes) which decreases blood flow
- most pronounced at area of direct skin contact
what is the cold induced vasodilation phenomenon?
following initial decrease in blood flow there is a later increase in blood flow, which cycles up and down
occurs when cold applied for > 15 minutes or when tissue temp reaches < 50 deg
** our goal is to vasoconstrict during the inflammatory healing phase
what are the neuromuscular effects of cryotherapy?
neuro effects:
1. pain reduction
- decreased nerve conduction velocity –> sensory and motor nerves
2. increased pain threshold by stimulation of cold receptors
- block perception of painful stimuli
muscular effects:
1. decreased spasticity (effects lasting 1-1.5 hours)
2. increase muscle strength (facilitating muscle contraction)
– < 5 min ice massage isometric strength increases
– cryotherapy for 30 min initial decrease then increase in strength
what are the metabolic effects of cryotherapy?
reduces inflammatory activity
cold decreases the rate of all metabolic reactions:
- decreases rate of inflammation by decreasing the activity of cartilage degrading enzymes and level of histamines
- decreases inflammatory processes due to joint diseases such as OA and RA
what does cryotherapy do during the acute inflammatory phase of healing?
bleeding decreased (vasoconstriction)
edema decreased (vasoconstriction and decreased metabolic activity)
pain reduced (neuromuscular effects of pain reduction, secondary pain effects of edema)
what does cryotherapy do?
directly decreases the heat and edema associated with inflammation by decreasing blood flow
when tissue temp remains normal the acute inflammation has probably resolved (48-72 hours)
what are two other ways cryotherapy benefits inflammation control?
acute chronic inflammatory diseases
post exercise
- reduce DOMS
what is edema?
presence of abnormal amounts of fluid in the extracellular tissue spaces of the body
what is the process of edema?
inflammation –> intravascular fluid pressure –> vascular permeability –> exudate into the interstitium
how does cryotherapy control acute edema?
reduce the release of histamines
increase blood viscosity
decrease blood flow
what is most effective to minimize edema?
apply ice ASAP
combine with compression and elevation (RICE)
drives extravascular fluid into venous and lymphatic drainage systems
what is a situation where cryotherapy would not be effective in minimizing edema?
controlling edema caused by immobility and poor circulation
what effects does applying cryotherapy for 10-15 minutes to control pain have?
neuro physiological effects
– gates pain transmission
hemodynamic physiological effects
– vasoconstriction
what is cryokinetics?
apply ice ASAP post injury until numbness
allows painfree exercise during period of numbness, 3-5 minutes, until sensation returns
repeat 5x
used frequently in athletics to minimize loss of playing time
what is cryostretch?
vapocoolant spray used as cooling agent
followed up with stretch to decrease muscle spasm, increase ROM
what are contraindications of cryotherapy?
cold hypersensitivity
cold intolerance
cryoglobulinemia
paroxysmal cold hemoglobinuria
Raynaud’s disease
over a regenerating peripheral nerve
over an area with circulatory compromise
what are precautions of cryotherapy?
over the superficial main branch of a nerve
over an open wound
hypertension
patient with poor sensation or mentation
very young or old patients
what does the use of heat in rehab medicine do?
control pain
increase soft tissue extensibility and circulation
accelerate healing
what are effects of thermotherapy?
accelerates tissue healing
pain management
alters collagen extensibility
what are hemodynamic effects of thermotherapy?
increased blood flow (vasodilation)
increased capillary permeability
superficial heating agents do not heat to the depth of most muscles
to heat deep muscles, use exercise or deep heating modalities
what are neuro effects of thermotherapy?
- increased nerve conduction velocity
- change frequency of nerve firing rate
– decrease muscle spasm –> muscle relaxation
– decreased spindle activity –> decreased resistance to passive stretch - increased pain threshold
– cutaneous thermoreceptors stimulated and gate pain (feels change in temp instead of pain)
what are muscular effects of thermotherapy?
altered muscle endurance and strength
– decrease during initial 30 min following heat
– after 30 min, for next 2 hours strength gradually recovers to above pretreatment levels
what are metabolic effects of thermotherapy?
increases rate of cellular biochemical reactions (increased metabolic rate)
increased oxygen uptake; accelerate healing
increase metabolic rate of destructive processes (avoid with inflammation)
increasing ______ of soft tissue increases its ________
temperature
extensibility
extensibility:
plastic deformation:
elastic deformation:
- amount of stretch/deformation that can occur
- can be achieved - tissue maintains increased length during stretching
- collagenous tissue stretched without prior heating can lead to elastic deformation
what are effects of heating soft tissue before stretching?
increase stretch
decrease risk of tearing tissue
achieves greater increase in length when stretching force is applied
less force is required to achieve the increased length
why would you use superficial heat in the clinic?
pain control
increase ROM, decrease joint stiffness
accelerated healing - increasing circulation and enzyme activity
infrared radiation for psoriasis or dermal ulcers
superficial muscle relaxation
what stages of healing are best to use heat with?
proliferative or remodeling stage
or when chronic inflammation is present
** DO NOT apply during acute inflammation phase
what occurs with superficial muscle relaxation?
change frequency of nerve firing
results in decreased firing frequency of alpha motor neurons (decreased muscle spasm)
good for LBP and spasms
what are contraindications of thermotherapy?
acute trauma
acute musculoskeletal and inflammatory conditions
recent or potential hemorrhage
thrombophlebitis
impaired sensation
impaired cognition
malignancy
what are precautions of thermotherapy?
pregnancy
poor circulation or thermal regulation
edema
cardiac insufficiency
areas with metal
over an open wound
areas where topical counterirritants have recently been applied
demyelinated nerves
what are adverse effects of thermotherapy?
- burns
– use hot packs vs electrical heating pads
– make sure pt doesn’t fall asleep - fainting
– vasodilation can lead to decreased blood flow to brain
– orthostatic effects following thermotherapy treatment - bleeding
- always give a patient a way to stop treatment
what is the down side to hot packs?
errors in application can lead to adverse outcomes –> burns
what are things to consider before using a hot pack?
no reimbursement
consider indications, contraindications & precautions
know patient medical history
monitor application of heat at all times
don’t fall into habit of using hot pack as passive modality
