Deep Heat Ultrasound- Therapeutic Procedures – Flashcards
82 test answers
Unlock all answers in this set
Unlock answers 82question
How do sound waves travel?
answer
Travel mechanically by deforming or vibrating moleulces. A vibrating molecule "bumps" into adjacent molecule, a chain reaction through the tissue. Mollecules closer together collide more quickly.
Unlock the answer
question
Relationship between tissue density and energy transfer speed?
answer
Sound energy travels faster through denser connective tissues such as tendon and bone.
Unlock the answer
question
Ultrasound on a large area?
answer
Not appropriate for large surface areas- its inefficient way of heating becuase of hte small area of the transducer.
Unlock the answer
question
How are sound waves produced in US?
answer
Waves are produced by a piezoelectric cystal: - Alternating current impressed on crystal causes molecules to collide & transfer energy - Crystal vibrates and produces mechanical waves equal to sound waves
Unlock the answer
question
2 kinds of effects from a piezoelectric crystal:
answer
1. thermal 2. mechanical
Unlock the answer
question
What kind of pattern do sound waves travel in?
answer
sinusoidal pattern through a medium. Positive pressure phase followed by a negative pressure phase.
Unlock the answer
question
Condensations
answer
areas of compression or increased molecular density
Unlock the answer
question
Rarefractions
answer
areas of decreased molecular density
Unlock the answer
question
Frequency: 1 MHz
answer
Deeper penetration Diverges more as leaves transducer
Unlock the answer
question
Penetration of 1 MHz:
answer
1-2 inches (greater than 2cm)
Unlock the answer
question
Tissues used for 1 MHz:
answer
Soleus, deep hip rotators for example
Unlock the answer
question
Frequency: 3 MHz
answer
Superficial Absorbed more easily, raises temp faster, less penetration
Unlock the answer
question
Tissues used for 3 MHz:
answer
Plantar fasciitis, patellar tendonitis, epicondylitis
Unlock the answer
question
Higher frequencies
answer
At higher frequencies, more frequent molecular oscillations occur, and increased work is required for sound waves to overcome molecular friction. This means more energy is absorbed in superficial tissues and less is available for deeper tissues.
Unlock the answer
question
Penetration of 3 MHz:
answer
1-2 cm
Unlock the answer
question
Temperature and frequency:
answer
At 3 MHz (superficial), tissue temperature increases much quicker and to a higher temperature. At 1 MHz (deep), tissue temperature takes much longer to increase, but stays heated for a longer time.
Unlock the answer
question
Continuous mode
answer
Uninterrupted stream of sound waves. Used for thermal effects.
Unlock the answer
question
Pulsed mode
answer
Periodic interruptions in sound waves. Energy flows for a brief duration, then no energy flows. Used for non-thermal effects, but has a mechanical effect on movement of ions across cell membranes. Characterized by a duty cycle
Unlock the answer
question
Duty cycle
answer
- Fraction of time during single pulse period that US beam is present - % of pulsed duration - On-time to the sum of on-time plus off-time Ex: 10 sec on, & 30 sec off (sum = 40 sec total time) 10/40 = 25% duty cycle
Unlock the answer
question
Intensity watts/cm2
answer
Determined by quantity of energy or acoustic power Not uniform across sound head (lower intensity around the sound head)
Unlock the answer
question
ERA: Effective Radiating Area
answer
A measure of the actual cross-sectional area of the US beam as it exits the metal plate Expressed in square centimeters (cm2)
Unlock the answer
question
Where does the sound head have highest/lowest intensity? why?
answer
Around the sound head = lowest Middle of sound head = highest Crystal is cemented around the periphery of the transducer, it cannot vibrate much so you don't get as much intensity out to the edge.
Unlock the answer
question
Biophysical characteristics of US:
answer
Can be transmitted, absorbed, reflected and refracted Depends on angle and type of tissue: greater energy is reflected at mm/bone interface 2° more drastic change in impedance
Unlock the answer
question
Acoustic Impedance
answer
Material / tissue's ability to transmit sound Molecular density & structure of material / tissue
Unlock the answer
question
Low impedance:
answer
If acoustic impedance is low, transmission is high & material absorbs little sound
Unlock the answer
question
Penetration and frequency:
answer
Lower frequency, deeper penetration Higher frequency, ↓'d penetration 2° ↑'d attenuation
Unlock the answer
question
Attenuation:
answer
A measure of the decrease in sound energy as the sound wave travels by absorption, reflection, or refraction ex: 3 MHz would be more appropriate to treat carpal tunnel.
Unlock the answer
question
Attenuation ex of 1 MHz
answer
lowest in blood, fat, muscle, blood vessel highest in bone, cartilage, tendon, skin
Unlock the answer
question
Angle of the US beam should be:
answer
should be <15 degrees from the perpendicular (more perpendicular to the tissue, best intensity)
Unlock the answer
question
Thermal effects of US:
answer
Deep heat
Unlock the answer
question
Tissue temp increase of 1 C:
answer
Increases metabolic rates
Unlock the answer
question
Tissue temp increase of 2-3 C:
answer
Decrease muscle spasm Decrease pain Increase blood flow
Unlock the answer
question
Tissue temp increase of >4 C:
answer
Necessary to increase collagen extensibility & inhibit sympathetic activity *stretch after or during to increase collagen extensibility
Unlock the answer
question
2 mechanical effects of US:
answer
1. microstreaming 2. cavitation
Unlock the answer
question
Microstreaming
answer
Small magnitude movements of ions & cellular fluids Alters cellular activity & cell membrane permeability
Unlock the answer
question
Cavitation
answer
Small gas bubbles present in body fluids are subject to compression during condensations & expansion during rarefactions, when exposed to US When exposed to high intensity US, may cause violent collapse or implosion of gas bubbles, leads to tissue destruction
Unlock the answer
question
US effects on muscle are dependent on:
answer
intensity, duration, frequency ex: 1 MHz can penetrate deeper but longer treatment times with higher intensities are required to achieve vigorours muscle heating
Unlock the answer
question
US effects on connective tissue:
answer
CT heats up faster & to higher temp than muscle
Unlock the answer
question
Differences between CT and muscle:
answer
CT more dense than mm (CT heats faster) Higher collagen content in CT CT more avascular (less blood vessels, blood flow not increased as much, also not as easy to cool down)
Unlock the answer
question
How does ERA effect temp?
answer
When Rx area 2 x ERA, aver temp ↑ 8 °C after Rx & returned to baseline after 20 min When Rx area 4 x ERA, temp ↑ 5 °C after Rx & returned to baseline after 15 min
Unlock the answer
question
If the intent of US is to maximize stretching...
answer
Stretching should be immediately after US or begin concurrently with it and continue for at least 4 min afterwards.
Unlock the answer
question
US effects on joint pain:
answer
May reduce pain in arthritis and stiffness
Unlock the answer
question
US effects on hemodynamics:
answer
Temp ↑'s in tissue as US energy is absorbed Local blood flow then increases to area to dissipate heat
Unlock the answer
question
US non-thermal effects:
answer
Reflexive vasodilation Local histamine release changes vascular tone
Unlock the answer
question
How long does it take blood flow to return to normal?
answer
Regardless of mechanism, blood flow returns to baseline < 1 minute after US
Unlock the answer
question
US effects on neurological system motor nerve conduction velocity:
answer
Motor nerve conduction velocities (MNCV) change Can ↑, ↓, or stay the same *Depends on parameter; pulse will stay the same, continuous mode may increase NCV.
Unlock the answer
question
US effects on neurological system sensory nerve conduction velocity
answer
Sensory nerve conduction velocities (SNCV) appear to ↑ with thermal US (Unclear whether solely due to temp changes, or other factors also) Somewhat unknown
Unlock the answer
question
US effects on pain threshold:
answer
Pain threshold increased 2° US effects / vascular / thermal changes Somewhat unknown
Unlock the answer
question
Thermal vs. non thermal:
answer
Thermal is achieved with continuous US 0.75-3.0 W/cm2 Non-thermal is achieved with pulsed US or low intensity continuous US
Unlock the answer
question
Treatment goal: thermal
answer
Gentle tissue temperature rise Low enough not to cause pain High enough for depth of penetration Long enough for heating to occur penetrate deeper? choose 1 MHz (longer wavelength). Increase duration for temperature increase.
Unlock the answer
question
Clinical uses: inflammation
answer
- Decrease pain with thermal, increase blood flow & nutrition (pain fibers more sensitive to US) - Edema has thermal & nonthermal effects
Unlock the answer
question
Clinical uses: tissue healing
answer
- ↑ # of tissue repair cells - ↑ collagen (need cont US), good for tendon/ligament healing - ↑ protein synthesis low intensity pulsed ultrasound can be used for fracture ealing.
Unlock the answer
question
Clinical uses: scar tissue
answer
relaxation of polypeptide vonds, increase mobility
Unlock the answer
question
Clinical uses: collagen extensibility
answer
Collagen good absorber of US Window for adding stretching to US
Unlock the answer
question
US Indications
answer
Contractures / scarring Chronic arthritis Muscle strain, spasm, hematoma MM guarding / trigger points / neuromas Subacute & chronic inflammation Wound healing
Unlock the answer
question
Contraindications
answer
Pacemaker (can use in more remote areas) Pregnancy Over pelvic/abd/ lumbar areas Malignancies / tumors (don't want to increase blood flow) DVT or thrombophlebitis Infected areas Spinal cord - laminectomy
Unlock the answer
question
Contraindications cont
answer
Growing bone, epiphyseal plate (damaging) Areas with tendency to bleed Eyes Over heart, carotid sinus, or cervical ganglia (HR influence)
Unlock the answer
question
Precautions
answer
Unhealed fx sites Primary repair of tendon or ligament Osteoporosis Plastic implants Metal implants
Unlock the answer
question
Repair of tendons/ligaments?
answer
Human studies of low-intensity US using treatment parameters similar to those found to be beneficial in animal models of tendon and ligament healing are absent in the literature.
Unlock the answer
question
3 methods of application:
answer
1. direct 2. indirect 3. phonophoresis
Unlock the answer
question
Indirect application: water immersion
answer
Irregular surface, small area Keep sound head 1-2 cm away Delivers only 32% as much energy vs. direct contact (need to increase duration due to decreased intensity)
Unlock the answer
question
Other methods of indirect application
answer
Fluid-Filled bag Fluid or gel filled Glove Gel pad MIST therapy-(Non contact) 40 kHz (low frequency/low intensity/nonthermal)
Unlock the answer
question
Phonophoresis
answer
Use Hydrocortisone (10%) dexamethosone or lidocaine with US gel Drives whole molecules into tissues, not ions Not supported by the literature
Unlock the answer
question
Deep heat rx set up:
answer
Explain Rx to patient Position the patient comfortably Remove clothing Appropriately drape Inspect area to be treated Determine patient's ability to respond to changes in temperature
Unlock the answer
question
US procedures:
answer
Follow general deep heat Rx set-up Select appropriate frequency Select continuous vs. pulsed If pulsed select duty cycle Use alcohol wipes to clean skin if oily or lotion on Apply coupling medium
Unlock the answer
question
Size of treatment area?
answer
Should be less than or greater to 2x ERA
Unlock the answer
question
Keep the transducer moving:
answer
smooth, rhymthmical area, longitudinal stroking or circular movements
Unlock the answer
question
Appropriate dosage time?
answer
5-10 minutes per site < 3 minutes no physiological effects 1 MHz takes 10 minutes to reach therapeutic temp 3 MHz faster **** LOOK AT CHART IN PPT for time/duration!!!
Unlock the answer
question
Procedures: US intensity
answer
Lower with more acute conditions, higher with chronic conditions or connective tissue shortening Patient dependent, ↓ if pain or dull ache 0.75-3.0 W/cm2 (↑ slowly if needed) Make sure transducer head is in contact when US is started, keep it moving!
Unlock the answer
question
Procedures cont
answer
Do not remove transducer from pt without shutting off machine first Conclusion of treatment: Shut off power Clean off gel Inspect the skin Clean the transducer Towel to remove gel Transducer cleaner spray
Unlock the answer
question
Document?
answer
Treatment area Pt position Frequency Mode Intensity (duty cycle) Treatment duration Application technique Transducer size Sequence within treatment session
Unlock the answer
question
Purpose of the gel?
answer
eliminate as much air as possible between the transducer & skin, maximizing US into pt body.
Unlock the answer
question
document example:
answer
1Mhz, 100% duty cycle, 2.0 W/cm2, 2cm2 sound head, 10 min
Unlock the answer
question
Frequency of treatments:
answer
Not well researched Usually max of 10-14 treatments recommended, but no evidence to support. Every other day, 2-3 x/week. Some suggest 2 week break before initiating US again What other options do you have? Is the patient progressing toward outcomes / goals?
Unlock the answer
question
Summary points:
answer
Need a larger sound head for larger area (treats 2x ERA size of sound head)
Unlock the answer
question
Why use an indirect treatmetn?
answer
Bony prominence. ALways use direct moethod unless you are on a bony prominence. Direct on muscle.
Unlock the answer
question
Acute ankle fracture?
answer
You can use US, but should use pulsed in the acute stages for non-thermal effects.
Unlock the answer
question
How do we get vasodilation with non-thermal?
answer
No temp increase- vasodilation due to muscle tone relaxing.
Unlock the answer
