Modalities Flashcards
What is the physical stress theory?
none/low = cell death low = atrophy normal = maintenance moderate = hypertrophy high = injury extreme = cell death
What is the physical stress equation?
exposure (magnitude) + duration + direction = stress placed on tissues
What is a therapeutic modality?
A stress placed upon the body to elicit an involuntary physiological response (correct form of energy + proper stage of healing = regeneration)
What occurs during primary trauma? What are you trying to avoid? What are you trying to elicit?
Primary trauma = cell death, inflammation & hemorrhage edema
Avoid = hypoxia, blood flow congestion, enzymatic injury, pain, spasm, atrophy
elicit = phagocytosis, blood clotting, revascularization, wound contraction, wound healing
When does secondary injury start?
30 mins after primary injury
What is the difference between swelling and edema?
swelling = fluid build up & increased capillary permeability (fluid leaves capillaries and enters tissue) edema = fluid and protein build up in interstitial space (can obstruct venous and lymphatic return)
What layers must ice go through?
skin, adipose tissue, fascia, muscle
What causes a greater depth of cryo penetration?
longer duration and larger treatment area
How does re-warming occur?
Deeper tissues are re-warmed by blood (increased cell metabolism) and skin temp is increased by blood & air
How long does intramuscular temperatures continue to decrease after removal of a cold modality? How long does intramuscular temp remain elevated after a heat modality?
30 mins for both
A 10 degree temp decrease of the skin causes a ___ degree temp decrease at a joint?
6.5 degrees
At what temperatures do certain events happen during cryotherapy (decreased blood flow, decreased cell metabolism etc.)?
- BF decreases instantly and levels out at 13 mins
- CSA of lymph vessels decrease at 15 degrees C
- Cell metabolism decreases at 10-15 degrees C
- Nerve changes occur at a skin temp of 5 degrees C
- P decreases and numbness occurs at 14.4 degrees C and P returns at 15.6 degrees C (approx 18-21 mins of ice application)
Does ice affect proprioception? If yes, for how long?
Yes, it affects proprioception for 5-10 mins after removal (decreased nerve conduction velocity and decreased perception of P)
What injuries could result from cold and compression application?
frostbite or cold-induced neuropathy
How does cold produce its effects physiologically (decreased P, edema formation etc.)?
blood = vasoconstriction, increased blood viscosity, decreased blood flow
edema = decreased cell metabolism, decreased secondary hypoxic injury (requires compression & elevation to remove edema)
pain = decreased nerve conduction velocity, decreased inflam/swelling (removes chemical and metabolic P triggers)
muscle spasm = decreased stretch reflex, decreased sensitivity of muscle spindles, decreased threshold of afferent nerve endings
How much does cold slow down a motor vs sensory nerve?
motor = 1.5m/sec
sensory = 2.6m/sec
(1 degree C intramuscular drop)
What is the law of Grotthus-Draper?
If energy is absorbed by one tissue layer it can’t be transmitted to deeper layers
What is Fouriers law?
The greater the temperature difference the faster the exchange of energy
Explain and provide an example of conduction, convection, conversion, radiation and evaporation
- conduction - transfer of heat by touching of two surfaces ex. ice pack
- convection - transfer of heat through the use of a medium (air/water) ex. whirlpool
- conversion - transfer of heat by changing one form of energy to another ex. ultrasound
- radiation - transfer of heat without the use of a medium ex. laser
- evaporation - heat is absorbed as the liquid turns into a gas ex. vapocoolant spray
What is the temperature for cold modalities versus thermal modalities?
cold = 10-18 degrees C heat = 40-45 degrees C
Which penetrates deeper and lasts longer, superficial cold or heat?
superficial cold
How much does exercise increase body temp and at what depth?
2.2 degrees C at 5cm
By what 4 methods is heat produced?
- transfer of thermal energy
- chemical action associated with cell metabolism
- mechanical action (therapeutic U/S)
- electrical or magnetic currents (diathermy)
When should you use cold versus heat?
cold = acute inflammation, before ROM exercises, after activity to decrease cell metabolism heat = subacute/chronic inflammation, promote venous drainage, encourage tissue healing, reduce edema/ecchymosis, improve ROM before activity
*Patient preference
What is the Q10 effect?
for every 10 degree C increase in temp, cell metabolism increases by 2-3x
What increases BF more, moist heat or dry heat?
moist heat (386% increase) dry heat (282% increase)
What is required to increase tissue elasticity?
increase tissue temp to 40-45 degrees C for 5 mins then stretch the tissue
What is rebound vasoconstriction?
after 20 mins of heating the vessels with automatically constrict to protect the deeper structures
How does adipose tissue affect heating/cooling?
Need to increase duration
20mm or less = 25 mins
20-30mm = 45 mins
30-40mm = 60 mins
What is inside an ultrasound head and how does it create heat?
piezoelectric crystal that expands and contracts (+ve and -ve electric charges)
What is the difference between longitudinal and transvers waves?
longitudinal = molecules are displaced parallel to direction of sound, travels through solid and liquid media (soft tissue) transverse = molecules are displaced perpendicular to sound waves, can only travel through solids (occurs when sound strikes bone)
Explain reflection, refraction and absorption
- reflection - beam goes in opposite direction (at an angle) when it strikes a surface
- refraction - beam continues in the same direction but is bent (speeds up if dense to less dense and slows down if less dense to dense)
- absorption - energy is converted to heat in a layer and cannot move to deeper layers
What is the effective radiating area (ERA)?
Small portion of transducer surface that produces ultrasonic energy
What are the differences between 1mhz and 3 mhz?
1mhz = low frequency, divergent, 5cm deep, slower absorption, retains heat 2x longer 3mhz = higher frequency, collimating, 2-3cm deep, faster absorption (3x), heat leaves faster
What is the beam nonuniformity ratio (BNR)?
ratio of the highest intensity within the beam with the average intensity (8:1 is unsafe)
What components of the body are highly reflective?
Bone
MTJ
Intermuscular interfaces
Air
What is cavitation, acoustical streaming and microstreaming?
Occur to produce non-thermal U/S effects.
1.cavitation = ultrasound produces pressure in tissue fluids which creates gas bubbles that expand and contract
2.acoustical streaming = bulk flow of fluids in one direction
3. microstreaming = fluids move in one direction across a boundary and can change cell structure/function
cavitation + acoustical streaming = microstreaming (increases cell membrane permeability)
What is the difference between direct current, alternating current and pulse current with examples
DC - uninterrupted flow of electrons from cathode to anode ex. iontophoresis
AC - uninterrupted flow of electrons is bidirectional (no true +ve or -ve) ex. IFC/TENS
Pulsed - flow of electrons is interrupted by periods of no electron flow (monophasic or biphasic) ex. NMES/Russian
What 4 factors affect current flow (resistance to flow)?
- Conductor material (blood & nerves are better than skin and bone)
- Length of circuit (shorter = less resistance)
- CSA of circuit (larger CSA = less resistance)
- Temperature of skin (warmer temp = less resistance)
What tissues are better suited to small pads vs large pads?
small pads = superficial nerves and decreased adipose tissue
large pads = deep nerves and increased adipose tissue
What 3 things can change how a nerve responds to electrical stim?
- Depth of nerve
- Diameter of nerve
- Phase duration of current
Name the nerves from superficial to deep
sensory nerves
motor nerves
pain fibres
muscle fibres
Why do motor nerves fire before pain fibres?
because P fibres have a smaller diameter so they take longer to depolarize
What is the difference between a normal muscle contraction and an electrically induced muscle contraction?
normal contraction =
- small –> large fibres
- contractions and recruitment are asynchronous to decrease fatigue
- GTO protect muscle from tension
- slow to fatigue
Electrically induced =
- large –>small fibres
- contraction and recruitment are synchronous
- GTO can not protect against tension
- quick to fatigue
What pps is required to reach tetany?
30-40pps
Can you get DOMS from electrical stim?
Yes
Can you increase strength on the opposite side of electrical stim? If yes, by how much? Why would you do this?
yes, by 10%
to delay atrophy or assist in re-education
What are the goals of electrical stim with parameters?
- Decrease Edema =
- 30-50 pps
- electrode proximal to edema
- 5-10s on 5-10s off
- ramp = 0.5s- none
- elevate body part and relax
- 10-20 mins daily - Muscle spasm
- 50-70pps
- on muscle group in spasm
- 10s on 10s off
- 1-2s ramp
- pt tries to relax
- 10-20 mins daily - Strength/re-ed
- 50-70pps
- electrode on muscle
- 10:50 (re-ed), 10:30 (strength)
- 2-3s ramp
- contract with on cycle
- 10-20 mins daily
What 4 things/domains contribute to how we interpret pain?
- evaluative- previous P experience
- sensory - nature of P stimulus
- affective - mental/emotional state
- misc - how everything combines into a feeling
How fast does a nerve fire?
33mph
What is the gate control theory?
Block painful stimulus from reaching the brain = pain relief
- stimulate A-beta fibres to reach the spinal cord first (only one sensation at a time can go up)
- A-beta = larger fibre, stimulates the SG and prevent P signal from going up
What is the opiate theory?
Allow painful stimulus to reach brain so that the body will release endogenous opiates
A-delta = large pain fibre (sharp/stinging)
C-fibres = small pain fibre (dull/aching)
Small fibres inhibit the SG and allow the pain signal to go up (releases enkephalin from pituitary to decrease P)
What else besides P relief can IFC do in a meh way?
edema reduction, decrease muscle spasm and bone stimulation
What are contras for cold application?
open wounds sensory deficit cold allergy cold sensitivity PVD thrombosis advanced diabetes Raynaud's Lupus Hemogolbinemia cold-induced miocardial ischemia
What are contras for heat application?
acute inflammation sensory deficit infection cancer PVD advanced arthritis thrombophlebitis impaired circulation poor thermal regulation DVT Pregnancy
What are contras for U/S application?
Same as heat for thermal, as well as unstable fracture pacemaker metal implants joint replacements organs breast implants eyes, heart, skull, carotid sinus, genitals
What are contras for electrical stim application?
seizures metal implants psychological impairments pacemaker sensory deficits infection blood clots pregnancy cancer unstable fracture arterial disease cardiac disability
