Physical Agents Flashcards
Thermal physical agents:
- ultrasound
- hot pack
- ice pack
- diathermy
Mechanical physical agents:
- mechanical traction
- elastic bandage/stockings
- whirlpool
- ultrasound
electromagnetic physical agents
- ultraviolet
- laser
- TENs
absolute contraindications of general physical agent use:
- pregnancy
- malignancy
- pacemaker
- impaired sensation
- impaired mentation
general effects of physical agents:
- changes rates of circulation (chemical reactions)
- alter fluid flow
- alter cell function
- increase membrane permeability and transport
- helps move more quickly through inflammation stage
- increases enzyme activity rate
- promotes collagen deposition
purpose of inflammation:
- dilute/dissolve cells or agents
- can be harmful if directed at wrong tissue or overly exuberant
cardinal signs of inflammation
- heat (increased vascularity)
- redness (increased vascularity)
- swelling (blockage of lymphatic drainage)
- pain (pressure, chemical irritation, pain sensitive structures)
- loss of function (pain and swelling)
vascular response to inflammation
- transient constriction (NE-injured)
- non-injured vasodilation
- increased permeability (edema)
- changed physical attraction between vessel walls
- in vasoconstriction and increased permeability: slowing of flow and increased viscosity
- extravasation
- transudate (serum once outside the cell)
- exudate
- pus
cellular reaction to inflammation:
- platelets: (RBC losts outside in exudate, severe injury)
- neutrophils (WBC activated for chemotaxis and phagocytosis, 0-24 hrs)
- monocytes/macrophages (most important; vessel to interstitial)
- lymphocytes (immune response via antibodies in chronic inflammation)
- basophils (release histamine)
parts of proliferation phase
-epithelialization
-wound contraction
-neovascularization
fibroplasia
maturation phase
-balance of collagen synthesis and lysis (collagen conversion)
stages of scar formation
Stage 1: deposition of type III collagen; scar prone to rupture
Stage II: increased fibroplasias; covnersion type III to type I collagen; wond contraction begins, remodeling at peak
Stage III: scar consolidation; remodeling decreases
Stage IV: remodeling beginning to cease; least responsive to intervention
what stage of scar formation has the greatest responsiveness to intervention?
Stage II
old definition of pain:
unpleasant sensation to warn of tissue injury and with an emotional response
new definition of pain:
: conscious correlate of the implicit perception that tissue is in danger, where the quality and intensity of the pain depend on the degree of perceived threat
a-delta nerve fibers:
- fastest conducting, first component of pain, leads to reflexive withdrawal
- myelinated
- short duration
- sense mechanical and thermal sensations
- sharp, pricking, temp. changes
c fibers:
(polymodal nociceptors) slow conducting; second component of pain -non myelinated -long duration -dull, ache, burning sensation -not well tolerated
what type is the majority of nociceptors?
c fibers
80%
primary afferent neurons:
a delta fibers
c fibers
a-beta fibers
a-beta fibers
transmit non painful sensations related to vibration, stretching, mechanoreception, abnormal pain
- skin, bones, joints
- large myelinated axons
- conduct faster than a delta or c fibers
opiopeptin system of pain modulation with external opioids:
\:inhibitory action by binding to opioid receptors in the brain and peripherally -presynaptic: prevent influx of Ca -postsynaptic: activate outflux of K -activates endogenous opioids -
naloxone:
antagonist to opiates
-higher affinity for opioid receptors
endogenous opiates
- stimulated by noxious, stressful sensory inputs
- bind to same opioid receptors
what modality stimulates edogenous opiates:
- e stim, burst or low rate modes
- acupuncture and painful stimulation
pain-spasm-pain cycle
-reflex
-nociceptor activation results in T-cell activation
-stimulates anterior horn cell to cause a muscle fiber to contract
-results in accumulation of fluid and tissue irritants and mechanicl compression of noviceptor
=increasing nociceptor activation
acute pain:
- sharp, localized, rapid onset, short duration
- appropriate response normally for pathoanatomical pain
referred pain
-occurs at site remote from source of
disease/injury
-no dorsal horn neurons (second order) dedicated to visceral; converge on somatic nociceptor 2nd order neuron
theories of referred pain:
- from a nerve to its innervation
- from one area to another derived from same dermatome
- from one area to another derived from the same embryonic segment
- converge on the same or similar areas of the spinal cord and synapse with the same 2nd order neuron
how do you differentiate between pain from visceral origin and musculoskeletal pain?
- MSK pain vaires with movement
- MSK pain varies with physical stress of tissue
persistent pain
- nociceptors are continually firing as long as a stimulus is present (can lead to persistent)
- episodic
- recurrent
- predisposing factors: poor physical condition, body mechanics, posture, etc.)
neuropathic pain
(disfunctional) -somatic nerves: intraneural extraneural associated with history of injury -SNS nerves: complex regional pain syndrome (CRPS)
examples of neuropathic pain from somatic nerves:
- radiculopathy
- sciatica
- phantom pain
chronic pain
(dysfunctional)
- dull diffuse, poorly localized
- slow gradual onset (3-6 months)
- unknown cause
- inconsistent behaviors
- fear avoidance
A high specific heat…
- requires more energy to heat up
- holds more energy at a given temp.
- more caution-have to apply at a lower temperature
highest to lowest specific heat of materials:
water skin muscle body as whole fat bone air
the greater the thermal conductivity=
faster transfer
ice has a ____ thermal conductivity than water
higher
- takes a lot of energy to convert ice to water
- ice causes more rapid cooling than water
the rate of temperature rise _____ in proportion to tissue thickness
decreases
convection
- contact with circulating medium (whirlpool; fluidotherapy)
- thermal agent is in motion
- transfer more heat in same period of time
blood is what kind of medium?
convective
conversion:
- conversion of non-thermal to thermal (mechanical, electrical, chemical)
- requires an intervening medium
- rate of transfer is affected by power of energy source, size of area, transmission, type of tissue
radiation
- no intervening medium or contact
- rate is dependent on: intensity, size of radiation source, area, distance from source, angle
- infrared lamps
cryotherapy/thermotherapy effect on pain:
decrease
decrease
cryotherapy/thermotherapy effect on muscle spasm
decrease
decrease
cryotherapy/thermotherapy effect on blood flow:
cry: decrease
therm: increase
cryo/thermotherapy effect on edema formation:
cry: decrease
therm: increase
cryo/thermotherapy effect on nerve conduction velocity:
cry: decrease
therm: increase
cryo/thermotherapy effect on metabolic rate:
cry: decrease
therm: increase
cryo/thermotherapy effect on collagen extensibility:
cry: decrease
therm: increase
cryo/thermotherapy effect on joint stiffness:
cryo: increase
cryo: decrease
cryo/thermotherapy effect on spasticity:
cryo: decrease
therm: no effect
cryo/thermotherapy effect on strength:
cryo: decrease
thermo: decrease
effects of cold:
- initial vasoconstriction (15-20 min)
- to protect other areas from getting cold
- not consistent cold induced vasodilation
hunting reaction:
-mediated by reflex to pain, or inhibition of smooth muscle by extreme cold
CIVD usually seen in:
distal extremities
neuromuscular effects of cold:
- decrease nerve conduction velocity (greatest effect on A-delta)
- increase pain threshold (velocity, edema decrease, gating…)
- altered muscle strength
- decreased spasticity(decreased gamma motor, afferent muscle spindle, GTO; greater than 30 min.)
at any given PO2, colder keeps…
o2 on the hemoglobin
metabolic effects of cold:
- decrease metabolic rate
- decreases degrading enzymes (collagenase, elastase, protease)
uses of cryotherapy:
- inflammation control (1st 2 days;vasoconstrition)
- decreases a-delta fiber activity (low level of cryotherapy) DOMS (under 15 min)
- edema control (decreased histamine, slow flow)
- pain control
- spasticity modification (even 5 minutes)
cryotherapy should not be used for edema control in what situations?
edema caused by immobility and poor circulation
cryokinetics:
icing to allow mobilization/ROM
cryostretch
reduces muscle spasm
contraindications for cryotherapy:
- cold hypersensitivity
- cold intolerance
- cryoglobulinemia
- paroxysmal cold hemoglobinuria
- raynaud’s disease
- over regenerating peripheral nerves
- over an area with circulatory compromise or peripheral vascular disease
precautions of cryotherapy
- over a superficial main branch of nerve
- over an open wound
- hypertension
- poor sensation or poor mentation
- very young and very old patients
non-freezing cold injuries:
- protracted exposure to low thermal conditions but no freezing of tissues
- injury to neuro-endotheliomuscular components of the walls of local blood vessels
- not sure if it is vascular or neural origin
documentation:
- area
- agent used
- duration
- position
- response
- temperature
- insulation/distance from patient
effects of heat:
- vasodilation
- neovascularization (rid body of excess heat)
- smooth muscle activation (via spinal cord reflexes and cutaneous thermo receptors for vasodilation)
with heat with substances are increased to lead to vasodilation?
bradykinin
nitric oxide
with increased temperature what is released to increase vasodilation?
histamine and prostaglandin
neuromuscular effects of heat
- nerve conduction velocity increases
- decreases conduction latency
- sodium channel changes
- increased pain threshold (spinal gating, decreased ischemia/muscle spasm)
muscle strength and heating:
- decreases initial 30 min.
- gradually increases until greater than preheating after 2 hours
metabolic effects of heat:
- increased metabolic rate
- increased oxygen uptake
- right shift of 02-hemoglobin curve
tissue extensibilty and heat:
- maintains plastic deformation better
- requires less force
uses of heat:
- pain control (gating from direct inhibition or increasing blood flow)
- psychological effect
- increased ROM
- accelerated healing
heat effect on oxygen availability:
oxygen availability
contraindications for thermotherapy:
- recent or potential hemorrage
- thrombophlebitis
- impaired sensation
- impaired mentation
- malignant tumor
- IR irradiation of the eys
precautions for thermotherapy
- acute injury/inflammation
- pregnancy
- impaired circulation
- poor thermal regulation
- edema
- cardiac insufficiency
- metal in the area
- over an open wound
- over areas where topical counterirritants have recently been applied
- demyelinated nerves
histamine is a:
vasoactive mediators
- increased vascular permeability
- vasodilation
nitric oxide is a:
powerful vasodilator
acoustic streaming
- non thermal effect
- circular flow of fluids
- transport of material across ultrasound field
microstreaming
- non thermal
- microscale eddying around the gas bubbles in oscillation from cavitation
duty cycle determines:
thermal/non thermal
frequency determines:
depth
ultrasound:
sound waves that transmit energy by alternately compressing and rarifying material
BNR
: Beam non-uniformity ratio
- intensity has higher peak in the middle of the head
- crystals are non uniform in their ability to vibrate and create heat
- usually 5:1 ratio
cavitation
The formation, growth, and pulsation of gas-filled bubbles caused by ultrasound.
piezoelectric:
- ability to generate electricity in response to a mechanical force or change shape in responses to an electrical current
- crystal needs to contract/expand at same frequency at which A current changes polarity
attenuation
the decrease in sound waves as it travels through tissue
high absorption coefficients:
-high collagen content
US well suited to heat:
tendons
ligaments
joint capsules
fasciae
thermal effects of US
- increased metabolic rate
- pain control
- reduced muscle spasm
- altered nerve conduction velocity
- increased circulation
- increased extensibility
- deeper reach
non thermal effects of US
- causes are mechanical
- increases intracellular calcium (alters enzymatic activity)
- increases cell membrane permeability
- promotes normal cell function
- increases histamine and NO
- promotes macrophage response
- increases protein synthesis
- increases proteoglycan synthesis
cause of compression/rarefaction?
crystal expanding/contracting with current which compresses material causing the US wave
US parameter for inflamed tendon/ligament:
0.5-1.0 W/cm2
pulsed 20%
contraindications with ultrasound
- malignant tumor
- pregnancy
- CNS tissue
- joint cement
- plastic components
- pacemaker
- thrombophlebitis
- eyes
- reproductive organs
ultrasound precautions
- acute inflammation
- epiphyseal plates
- fractures
- breast implants
sound head movement speed:
4 cm/sec
treatment area with US
2x ERA- 4x ERA
