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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
Q

reflection

A

occurs when ultrasound waves bounce back from obstacles and boundaries to the ultrasound wave

known as the standing wave

clinical significance

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26
Q

clinical significance of reflection

A

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

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27
Q

hot spot –> reflection –> clinical significance

A

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

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28
Q

refraction –> acoustic impedance

A

ultrasound wave bounces at angle away from the ultrasound

29
Q

production of heat

A

heat is produced by the absorption of ultrasound waves

structures with high absorption will get heated much easier

30
Q

order of low to high absorption

A

water

blood

fat

muscles

tendons

cartilage

peripheral nerve

bone

31
Q

advantages as a heating modality

A

ability to heat deep structures w/o heating superficial structures

skin and fat can be bypassed

32
Q

types of ultrasound

A

continuous

pulsed

33
Q

continuous

A

sound intensity is constant throughout the treatment

ultrasound is absorbed 100% of the time

produces much more heat than pulsed

34
Q

pulsed

A

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
Q

effective radiating area

A

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
Q

beam non-uniformity ratio

A

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
Q

clinical significance –> BNR

A

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
Q

ultrasound parameters

A

frequency

duty cycle

measuring energy

39
Q

frequency

A

defined as a number of wave cycles completed during each cycle

ultrasound frequency is either 1 MHz or 3 MHz

40
Q

1 MHz

A

less energy is absorbed in the superficial tissue and there is greater penetration

tissue healing occurs slower

41
Q

3 MHz

A

there is much more superficial heating

tissue heating occurs slower

42
Q

duty cycle

A

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
Q

measuring energy

A

power

intensity

44
Q

measuring energy –> power

A

measured in watts

defined as the electrical energy delivered to the crystal

45
Q

intensity

A

measured in watts/cm2

refers to the avg power delivered over the ERA

46
Q

therapeutic use –> intensity

A

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
Q

acute

A

.1-.5 W/cm2

no heat for pt

48
Q

subacute

A

.5-1.0 W/cm2

no to minimal heat felt by pt

49
Q

chronic

A

1.0-2.0 W/cm2

heating/warmth felt by pt

50
Q

non-thermal

A

no temp increase

used for acute injury, edema, healing

51
Q

mild thermal

A

1 degree C temp increase

subacute injury or hematoma

52
Q

moderate thermal

A

2 degrees C increase

used for chronic inflammation, pain, trigger points

53
Q

vigorous

A

4 degrees C increase

used for stretch collagen

54
Q

acute condition (specifics)

A

tissue repair

low intensity

pulsed (0.5 W/cm2) for non thermal effect

55
Q

chronic condition

A

muscle spasm or stiffness

high intensity

continuous (1-3 w/cm2) for thermal effect

56
Q

ultrasound delivery techniques

A

direct contact

immersion

bladder

57
Q

direct contact –> delivery

A

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
Q

how much gel should be applied to the transducer

A

1-2 millimeters

too little –> burn the pt

too much –> cause air pockets

59
Q

what should we try to exclude

A

air so that most of the sound energy has ability to penetrate tissue

60
Q

immersion technique

A

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
Q

underwater coupling

A

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
Q

bladder technique

A

balloon or surgical glove filled with water

only 50% of energy enters the tissues

technique is not usually recommended

63
Q

phonophoresis

A

delivery of meds into the body via ultrasound

transdermal drug delivery as sound waves push meds deep into the body

64
Q

treatment parameters –> phonophoresis

A

frequency = 3 MHz

duty cycle = 20%

duration = 5-10 min for an area 2-3 times the size of the ERA

65
Q

advantages –> phonophoresis

A

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
Q

indications –> phonophoresis

A

muscle soreness

tissue inflammation

tendonitis

bursitis

strains/sprains

epicondylitis

67
Q

common medications used –> phonophoresis

A

hydrocortisone

lidocaine

iodine

salicylate

zinc

68
Q

documentation

A

record specific parameters

PTI II part 2 (9 decks)

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