Cryotherapy Flashcards
(30 cards)
What is cryotherapy?
Transfer of energy away from the region
- Cooling is achieved by removing heat from an object/body part
What are the methods of energy transfer?
- Conduction
- Convection
- Evaporation
What are some examples of conduction?
- Ice packs
- Ice massage
- Controlled-cold units
- Cold/Cool immersion (along w convection)
Example of convection?
Cold/cool immersion (movement of immersed body part/water frm turbines)
Example of evaporation?
Vapocoolant sprays
What is conduction?
- Transfer of heat by direct interaction of the molecules in the warmer area with those in the cooler area
- Warmer, rapidly moving particles give up/transfer heat to nearby cooler, slower-moving particles
What is ice massage?
- Applied over a small area using overlapping strokes/circles (muscle belly, tendon, bursa, trigger points)
- Applied 5-10 mins
What are the sensations patient may experience during ice massage?
- Cold
- Burning (usually pass within 1-2 min)
- Aching (usually pass within 1-2 min)
- Numbness
What is convection?
Occurs when there is direct contact b/w skin & moving fluid particles
e.g. cold whirlpool (water moves over patient’s skin)/patient moves body part in the water
Evaporation through the use of vapocoolant sprays
- Made of coolant liquid
- Used for myofascial pain & trigger point release
- Spray in unidirectional sweeps along the muscle over trigger point areas (12-18 inches away from skin) then do passive stretching exercise
- Spray 30-60 sec & repeat 3-5 times
What is a cryocompression unit?
- Manual circulation of cold water through a cuff
- Applied over an extremity
- Compression: Achieved by pressure exerted from the filled cuff & wrapped ard joint/extremity
- Used after surgery
What are the factors influencing cryotherapy?
- Treatment temperature
- Time of exposure
- Thermal conductivity
- Area of tissue affected
- Depth of tissue (deep vs superficial)
- Form of cold therapy
- Post-treatment activity
How does treatment temp influence cryotherapy?
Greater diff in heat (b/w body part & treatment thing e.g. ice pack) = Faster heat transfer
How does thermal conductivity influence cryotherapy?
Tissues w high water content (e.g. muscle) = better thermal conductivity than adipose tissue
What are the physiological effects of cryotherapy?
- Dec. histamine & bradykinin = dec. vasodilation
- Inc smooth muscle tone = vasoconstriction
- Dorsal root ganglion stim. = vasoconstriction
- Inc. blood viscosity = dec blood flow (1, 2, & 3 also dec. bld. flow)
How does the area of tissue affected influence cryotherapy?
Thermal barrier = adipose tissues
If thinner = less time needed for heat trnfs
Cold-induced vasodilation (CIVD)/Hunting response
- Late/delayed response to high dosage of tissue cooling = some areas e.g. foot, elbow, lips, cheek, ears, nose (prevent frostbite)
- Mediated by axon reflex in response to pain of prolonged cold/extreme low temp
- Sustained cold = dec. release of neurotransmitters from sympathetic nerves to muscle walls of arteriovenous anastomosis (hand & feet)
- Highly likely to occur in distal extremities in applications of <1°C longer than 15 min
What are the neuromuscular effects of cryotherapy?
- Nerve conduction velocity decreases
- Pain threshold increases & pain decreases
- Muscle strength, balance etc affected (reduced)
- Reduced spasticity
Nerve conduction velocity decreases due to cryotherapy
- Decreases in both sensory & motor nerves (superficial cooling applied to skin 5 mins & longer)
- If cooled 5 mins/longer = reverses in ~15 mins (normal circulation)
- If cooled 20 mins = reverses in ~30mins/longer (bc nerve temp reduced)
- Largest effect on conduction by myelinated & small fibres (e.g. A-delta fibres)
(smallest effect on conduction by unmyelinated & large fibres)
What precaution must be taken when applying cryotherapy over major nerve areas?
Shorter application duration = must allow action potential propagation to occur
- Peroneal nerve (lateral aspect of knee)
- Ulnar nerve (elbow)
Inc. pain threshold & dec pain due to cryotherapy
When cold applied, cutaneous cold receptors are stimulated = cold & light touch sensation overrides the nociceptor fibres = override pain receptors = block transmission of painful stimuli to brain cortex = inc. pain threshold &. dec. pain sensation
- Gate control mechanism & reduction of muscle spasm (interrupt pain-spasm-pain cycle)
- Slow sensory nerve conduction velocity
- Reduction of postinjury edema = dec pain prod. by compression of nerves & sensitive structures
Muscle strength, balance, etc affected by cryotherapy
- Muscle strength dec = dec bld flow to muscles, slowed motor nerve conduction, inc. muscle viscosity, inc. joint/soft tissue stiffness
- Strength assessments = performed before/several hours after
- Accuracy, balance, proprioception stuff = avoid for period of time after application
Reduced spasticity due to cryotherapy
Temporarily
- Initial cooling response = likely due to reflex rxn to stimulation of cutaneous cold receptors reducing gamma motor neuron activity
- Cooling for 10-30 mins = reduced discharge from afferent spindles & golgi tendon organs bc dec. muscle temp; effects lasts ~1-1.5 hours after cooling
What are the metabolic effects of cryotherapy?
- Dec. metabolic rate (rxns involved in inflammation)
- Cartilage-degrading enzymatic activity dec.
(e.g. collagenase, elastase, hyaluronidase, protease) - Level of histamine dec.
