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Physical Agents > Therapeutic Ultrasound #2 > Flashcards

Therapeutic Ultrasound #2 Flashcards

1
Q

Acute Effects of Therapeutic Ultrasound Delivered at Varying Parameters on the Blood Flow Velocity in a Muscular Distribution Artery

A

Conclusion: 1.0 MHz ultrasound delivered at 1.0 and 1.5 w/cm2 to the triceps surae musculature as described in the present study can increase the blood flow velocity in the popliteal artery.

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2
Q

A Comparison of Human Muscle Temperature Increases During 3-MHz Continuous and Pulsed US With Equivalent Temporal Average Intensities

A

Pulsed US produces similar increases in intramuscular temperature as continuous US given equivalent SATA intensities

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3
Q

1.8°F(1°C) mild heat temp increase effects

A

Increase metabolism

Reduces mild swelling

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4
Q

3.6-5.4°F(2-3°C) Moderate heat temp increase effects

A

Reduces pain and muscle spasm

Increases blood flow

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5
Q

7.2°F(4°C) Vigorous heat temp increase effects

A

Increases ROM and tissue extensibility

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6
Q

Factors that influence tissue temperature rise from US

A
  • Rate at which energy is applied
    • Intensity and mode of application
  • Length of time energy is applied
  • The thermal conductivity of the tissue
    • Bone has high absorption coefficient and high thermal conductivity.
    • Heat is dissipated to cooler, nonsonated areas
  • Rate of perfusion of blood to the tissue
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7
Q

Nonthermal effects of US

A
  • Increased histamine release
  • Influx of calcium ions
  • Increased phagocytosis of macrophages
  • Increased protein synthesis
  • Increased capillary density of ischemic tissues
  • Tissue regeneration
  • Wound healing
  • Cell membrane alteration
  • Attraction of immune cells to the injured tissues
  • Increased fibroblast activity
  • Vascular regeneration
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8
Q

Physiological effects: nonthermal effects

A

-Originate at cell membrane
-Membrane deforms slightly due to pressure against cell wall
-Due to micromassage, microstreaming, and cavitation
-Frequency response theory
*Specific frequency will cause specific tissue resonance
-Attraction of Immune Cells to Injured Area
Alters Cell Membrane Properties
*Cellular adhesion
*Membrane permeability
*Calcium influx
*Cellular proliferation
*Activation of signal-transduction pathway

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9
Q

US in inflammatory phase

A 
Aid immune response:
 -Inducing vasodilation
 -Activation of adhesion   molecules
How?
 -Modulating signal transduction pathway
  *Series of enzymatic proteins
  *US alters protein structure (phosphate moderation
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10
Q

US in Repair phase

A

Immune response:
-Induce tissue debris clearance
-Stimulate tissue remodeling
How?
-Anti-inflammatory cytokines down-regulate T-cells
-Redirect cellular activity toward proliferation

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11
Q

Frequency response hypothesis: central premise

A
  • US mechanical energy is absorbed by proteins
  • Alters structural conformation of protein
  • Modulates protein function
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12
Q

Incisional Wound Healing: A Controlled Study of Low and High Dose Ultrasound

A

Conclusion: Both low and high dose US increased the wound breaking strength and collagen deposition in incisional wounds

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13
Q

Frequency response hypothesis: Frequency resoonance

A

Each frequency of US may have a unique resonant or shearing force. This may effect proteins differently. Looking at targeted effect of frequency on proteins.

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14
Q

Efficacy studies

A 
Positive benefit AND no benefit
-Ankle sprains
- elbow epicondylitis
-carpal tunnel snydrome
- calcific tendonitis of shoulder
Just positive benefit
- myofascial pain
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15
Q

Why discrepancy in efficacy studies?

A
  • TUS provides effect at impairment level.
  • Studies often do not report impairment being studied.
  • Studies often do not report stage of healing.
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16
Q

Therapeutic US clinical uses

A
  • Aiding the inflammatory response to injury
  • Connective tissue healing
  • Superficial wound healing
  • Bone healing
  • Pitting edema
  • Reducing muscle spasm
  • Reducing pain
  • Restoring ROM due to scar/contracture
  • Stretching connective tissue
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17
Q

US aiding inflammatory response

A
  • Stimulates collagen synthesis
  • Stimulates cell proliferation
  • Stimulates release of histamine

Parameters

  • Pulsed 20% duty cycle,0.5 W/cm2, 5 minutes
  • Continuous, 0.1 W/cm2, 5 minutes
18
Q

US for CT healing

A

Many animal studies demonstrated positive effects to stimulate cartilage growth, tendon repair, nerve repair

19
Q

US for superficial wound healing

A
  • Increased fibroblast production of collagen
  • Increased blood vessel development
  • Increased smooth muscle activity
20
Q

US for bone healing

A
  • Nolte et al, J Trauma, 2001;51:693-702
  • Pulsed, low intensity US assisted in healing non union fractures
  • Parameters:
    • Duty cycle:20%
    • Frequency: 1.5MHz
    • Intensity: 30mW/cm2
    • Time: 20 min
21
Q

US for pitting edema

A
  • Draper et al.
  • Heating effect from US will liquefy gel-like cellular debris in pitting edema
  • Will aide in allowing fluid to be removed by massage, elevation, etc.
22
Q

US for reducing muscle spasm

A
  • Increases blood in area
  • Removed irritants
  • Reduces pain cycle
  • Increases 02 delivery to tissues
23
Q

US for Reducing pain

A
  • Altering transmission or perception of pain

- Modifying underlying condition causing pain

24
Q

US for reducing pain: altering transmissionor perception of pain

A
  • Selectively heats peripheral nerve
  • May alter or block impulse conduction
    • parallel relationship between increased tissue temp and increased sensory nerve conduction velocity
    • speed of conduction increase as tissue temp inc
  • Increase nerve cell membrane permeability
  • Increase tissue metabolism
25
Q

US contraindications

A
  • Near a malignant or benign tumor
  • Near the uterus of a pregnant female
  • Central nervous system tissue
  • Over cemented joint replacement
  • Near a pacemaker
  • Near a suspected thrombophlebitis
  • Over the eyes, ears, and genitalia
  • Near an area with infection
  • Over areas that have recently been exposed to radiation and radioactive isotopes
  • Over areas with active bleeding or susceptible to hemorrhage
26
Q

US precautions

A
  • Acute Inflammation
  • Epiphyseal Plates
  • Fractures
  • Breast Implants
27
Q

US dosimetry

A
  • Typically 0.5 – 2.0 w/cm2 for 5-10 minutes
  • However, need to know:
    • Stage of healing
    • Treatment area size
28
Q

US dosimetry: Therapeutic dose

A
  • The amount of acoustic energy delivered to the tissue per square centimeter
  • Measured in J/cm2
    • Takes into consideration relationship between total treated area (S) and the sound head ERA
29
Q

Therapeutic dose: calculate total energy (E)

A

E=P(power) X T(time) (1J = 1W/sec.)

30
Q

Therapeutic dose: Calculate total energy delivered per sound head square cm

A

Es (Energy/cm2 of sound head) = E/ERA

31
Q

Therapeutic dose: Calculate therapeutic dose

A

D = Es/(S (treated area) /ERA)

32
Q

Therapeutic dose: TX area

A

2-3 times ERA

33
Q

Therapeutic dose: frequency to tx

A

Depends upon level of US being used
Depends upon the stage of healing
*Thermal – sub acute to chronic stage
*Non-thermal – acute stage

34
Q

Therapeutic dose: duration of intervention

A
  • Depends upon desired effect of treatment
  • No definitive, objective standard exists
  • Acute conditions may be treated for shorter periods than chronic conditions
  • Smaller areas require less time than larger areas
35
Q

Duration of intervention : subactute

A
  • Tx. Area = 30 cm2
  • ERA = 10 cm2
  • Time = 30cm2/(.67 X 10cm2) = 4.5 minutes
36
Q

Duration of intervention: chronic

A
  • Tx. Area = 30 cm2
  • ERA = 10 cm2
  • Time = 30 cm2/(.5 X 10cm2) = 6 minutes
37
Q

Duration of intervention: Max thermal

A
  • Tx. Area = 30 cm2
  • ERA = 10 cm2
  • Time = 30 cm2/(.4 X 10cm2) = 7.5 minutes
  • Tx. Area = 2xERA = 5 min
  • Tx. Area = 3xERA = 7.5 min
  • Tx. Area = 4xERA = 10 min
38
Q

Therapeutic dose: intensity

A
  • Acute conditions (non thermal effects)
    • 0.1-0.5 W/cm2
    • Pt should feel NO warmth
  • Sub acute conditions (non thermal effects)
    • 0.5-1.0 W/cm2
    • Pt should feel none to minimal warmth
  • Chronic conditions (thermal effects)
    • 1.0-2.0 W/cm2
39
Q

Coupling Medium

A
  • Sound waves do not travel well through air.
  • They reflect off most structures
  • Need a mechanism to connect US to tissue
    • Conductive (aqueous) coupling gel, glycerol contact coupling, Hydrogel sterile wound dressing, & water (degassed) coupling
40
Q

Couplant

A

– any agent that allow for smooth transmission of US from sound head to tissue (skin)
* water > min oil> US gel (ultraphonic) > US lotion (polysonic)

Physical Agents (21 decks)

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