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PTI II part 2 > ultrasound > Flashcards

ultrasound Flashcards

1
Q

definition

A

inaudible, acoustic vibrations of high frequency that may produce either thermal or non thermal physiologic effects

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2
Q

rationale

A

to introduce thermal and mechanical effects

to help with tissue repair and pain relief

to facilitate wound debridement

to promote and accelerate bone growth

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3
Q

how does ultrasound affect pain

A

decreases pain

–> via elevation of pain threshold by activating thermal receptors

–> reduces inflammation

–> reduces muscle spasm

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4
Q

contraindications

A

in conjunction w/ x-rays, radiation or radioactive isotopes

over the eyes, carotid sinus, testes, epiphyseal plates , cemented prosthetic, cervical ganglia, heart, pacemakers and bony prominence

pt w/ cancer, severe or acute cardiac dzs, thrombophlebitis

over pregnant uterus, over spinal cord after a laminectomy, over an infection

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5
Q

precautions

A

unhealed fx sites

joint cement

primary repair of tendon or ligament

reproductive organs

impaired circulation

acute inflammation

osteoporosis

plastic or metal implants

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6
Q

thermal ultrasound effects

A

increases extensibility of collagen and blood flow

decreases joint stiffness and muscle spasm

helps to relieve pain

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7
Q

thermal ultrasound benefits

A

increasing collagen extensibility

decrease in joint stiffness

decrease in muscle spasm

decrease in pain

increased blood flow

increased inflammatory response

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8
Q

thermal ultrasound disadvantages

A

can only heat a small area

no more than 2 times the head of the transducer

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9
Q

non-thermal ultrasound effects

A

increases macrophage responsiveness

increases blood flow and membrane permeability

aids in soft tissue repair

provides pain relief

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10
Q

nonthermal ultrasound key note

A

there is still some sort of heat occurring during any duration of this treatment

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11
Q

advantages of non thermal ultrasound

A

increases the healing process

–> stimulation of fibroblast activity
–> increased protein synthesis
–> increased blood flow

benefits during all 3 stages of healing

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12
Q

how does nonthermal ultrasound work

A

cavitation

acoustic micro steaming

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13
Q

cavitation

A

defined as the formation of gas filled bubbles that expand and compress b/w of ultrasonically induced pressure changes in tissue fluids

increase its flow in fluid around the vibrating bubble

increases cell membrane permeability which increases as intensity increases

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14
Q

acoustic micro steaming

A

the movement of fluids along the boundaries of cell membranes

results in change in cell wall permeability which allows healing to occur

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15
Q

transmission of acoustic energy

A

uses molecular collision

by using a coupling medium –> absorption is enhanced by causing vibration

through the medium there is a minimum amount of displacement to the surrounding tissues

eventually the wave of vibration is propagated through the entire medium

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16
Q

wave transmition

A

2 types of waves

longitudinal

transverse

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17
Q

longitudinal

A

molecules are displaced in a direction the wave travels

particles become compressed and decompressed

can travel through solids and liquids

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18
Q

transverse

A

molecules are displaced at right angles to the direction the wave travels

particles become compressed and decompressed

only travel in solids

frequency of wave transmission

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19
Q

frequency of wave transmission –> transverse waves

A

acoustic sound is transmitted between 16 kHz and 20 kHz

therapeutic ultrasound is b/w .75 and 3 MHz

the greater the frequency the more focused the beam

the lower the frequency the greater the dept of penetration

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20
Q

components

A

high frequency electrical generator and transducer

transducer

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21
Q

components –> transducer

A

known as the applicator or sound head

composed of piezoelectric crystal such as quartz or synthetic ceramic

crystal converts electrical energy to acoustic energy through mechanical deformation

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22
Q

reverse piezoelectric effect

A

occurs when AC electrical current runs through a crystal

will cause the crystal to expand and contract which causes production of ultrasound

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23
Q

attenuation

A

transmission through various tissues reduces the intensity of ultrasound energy

decreased intensity is due to absorption of that energy as it passes through tissues

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24
Q

acoustic impedance

A

defined as the reflection or refraction of a sound wave

occurs when it encounters a boundary or an interference b/w 2 tissues

reflection

refraction

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25
reflection
occurs when ultrasound waves bounce back from obstacles and boundaries to the ultrasound wave known as the standing wave clinical significance
26
clinical significance of reflection
99% reflection from metal to air is why a gel must be used also why you must never turn on the machine which transducer in the air hot spot
27
hot spot --> reflection --> clinical significance
repetition of a continuous wave when the path of new and reflected waves coincide results in the sum of both waves can result in a severe internal burn to prevent must move head continuously
28
refraction --> acoustic impedance
ultrasound wave bounces at angle away from the ultrasound
29
production of heat
heat is produced by the absorption of ultrasound waves structures with high absorption will get heated much easier
30
order of low to high absorption
water blood fat muscles tendons cartilage peripheral nerve bone
31
advantages as a heating modality
ability to heat deep structures w/o heating superficial structures skin and fat can be bypassed
32
types of ultrasound
continuous pulsed
33
continuous
sound intensity is constant throughout the treatment ultrasound is absorbed 100% of the time produces much more heat than pulsed
34
pulsed
interrupted intensity there's an on off time no energy is produced during off period duty cycle refers to the on time utilized early on during the healing b/c there is little heat produced
35
effective radiating area
defined as the surface of the transducer producing the sound wave dependent on the surface area of the crystal usually the perimeter of the transducer has no therapeutic effect
36
beam non-uniformity ratio
define as the variability of ultrasound beam intensity the lower the BNR the more uniform the output of the machine FDA is acceptable b/w 2 and 6 optimally want 1:1 ration but acceptable up to 6:1 ration clinical significance
37
clinical significance --> BNR
the higher the BNR the greater the likelihood of tissue damage the lower the BNR the less chance of hotspots the higher the BNR the faster one must move the transducer to safely treat the pt
38
ultrasound parameters
frequency duty cycle measuring energy
39
frequency
defined as a number of wave cycles completed during each cycle ultrasound frequency is either 1 MHz or 3 MHz
40
1 MHz
less energy is absorbed in the superficial tissue and there is greater penetration tissue healing occurs slower
41
3 MHz
there is much more superficial heating tissue heating occurs slower
42
duty cycle
defined as the percentage of time that the ultrasound is actually on equated by duration of pulse (on time) divided by pulse period (on + off)
43
measuring energy
power intensity
44
measuring energy --> power
measured in watts defined as the electrical energy delivered to the crystal
45
intensity
measured in watts/cm2 refers to the avg power delivered over the ERA
46
therapeutic use --> intensity
b/w .25 watts/cm2 - 3 W/cm2 usually b/w .5 and 2 depends on goal of the treatment too much will cause damage too little will have no effect
47
acute
.1-.5 W/cm2 no heat for pt
48
subacute
.5-1.0 W/cm2 no to minimal heat felt by pt
49
chronic
1.0-2.0 W/cm2 heating/warmth felt by pt
50
non-thermal
no temp increase used for acute injury, edema, healing
51
mild thermal
1 degree C temp increase subacute injury or hematoma
52
moderate thermal
2 degrees C increase used for chronic inflammation, pain, trigger points
53
vigorous
4 degrees C increase used for stretch collagen
54
acute condition (specifics)
tissue repair low intensity pulsed (0.5 W/cm2) for non thermal effect
55
chronic condition
muscle spasm or stiffness high intensity continuous (1-3 w/cm2) for thermal effect
56
ultrasound delivery techniques
direct contact immersion bladder
57
direct contact --> delivery
occurs when direct contact is made b/w the ultrasound transducer and pt with a medium in b/w surface must be larger than the transducer be certain to utilize enough medium
58
how much gel should be applied to the transducer
1-2 millimeters too little --> burn the pt too much --> cause air pockets
59
what should we try to exclude
air so that most of the sound energy has ability to penetrate tissue
60
immersion technique
used when the treatment area is smaller than the transducer head used when treatment area is irregular used when a bony prominence makes direct contact difficult underwater coupling 32% less energy is absorbed 40-60% less effective than direct contact for thermal purposes to compensate increase intensity
61
underwater coupling
immerse body part in basin filled with water establish treatment duration depending on size of area to be treated maintain sound head parallel to treatment surface at a distance of .5 to 3 cm move sound headed circular or linear overlapping strokes at rate of 2-4 inches per second
62
bladder technique
balloon or surgical glove filled with water only 50% of energy enters the tissues technique is not usually recommended
63
phonophoresis
delivery of meds into the body via ultrasound transdermal drug delivery as sound waves push meds deep into the body
64
treatment parameters --> phonophoresis
frequency = 3 MHz duty cycle = 20% duration = 5-10 min for an area 2-3 times the size of the ERA
65
advantages --> phonophoresis
medication is spread over the local area increase concentration at delivery site non invasive medication bypasses the liver avoid pain, trauma, infection via injection prevents gastric irritation
66
indications --> phonophoresis
muscle soreness tissue inflammation tendonitis bursitis strains/sprains epicondylitis
67
common medications used --> phonophoresis
hydrocortisone lidocaine iodine salicylate zinc
68
documentation
record specific parameters

PTI II part 2 (9 decks)

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