Therapeutic Ultrasound Flashcards
What is therapeutic ultrasound?
Type of sound wave
Frequency is greater than 20,000 Hz (Cycle per second)
Exceeds the limits of normal human hearing
What is the physical effect of ultrasound?
Thermal & Non-thermal
What does the thermal effect of ultrasound do?
Increase tissue temp
What does the non- thermal effect of ultrasound do?
Acoustic streaming
Microstreaming
Cavitation
May alter cell membrane permeability
What type of ultrasound do you use to produce thermal effects?
Continuous
What type of ultrasound do you use to produce non thermal effects?
Pulsed
What are the thermal effects of ultrasound?
Acceleration of metabolic rate
Reduction or control of pain & muscle spasm
Alteration of nerve conduction velocity
Increased soft tissue extensibility
True or false: Ultrasound heats tissue with a high absorption coefficient more than tissues with low absorption coefficents
True
Is ultrasound ideal for heating muscles>
No b/c muscle has relatively low absorption coefficient & most muscle are larger than transducer
True or False: Tissues with higher absorption coefficients generally have higher collagen content
True
What factors affect the amount of temperature increase?
Tissue
Frequency
Intensity
Duration
What is one big thing that does not affect the amount of temperature increase?
Speed does not affect temperature change
What can happen if ultrasound intensity is too high? And what should you do?
Patient will most likely complain of deep ache because you are overheating the periosteum
You should reduce ultrasound intensity immediately
What can happen if ultrasound intensity is too low>
Patient will not feel any increase in temperature
What should tissue temperature be when using ultrasound?
40-45 *C
What is cavitation?
Formation, growth, & pulsation of gas filled bubbles caused by ultrasound
What is Microstreaming?
Microscope Eddying that occurs near any small vibrating ultrasound
What is acoustic streaming?
Steady circular flow of cellular fluids induced by ultrasound
What are some clinical indications for ultrasound?
- Soft tissue shortening
- Pain control
- Soft tissue healing
- Tendon & ligament injuries
- Bone Fx
- CTS
- Phonophoresis
How can ultrasound aid in pain control?
- Stimulation of cutaneous thermal receptors
- Increased soft tissue extensibility
- Changes in nerve conduction
- Modulation of inflammation
How can ultrasound aid in soft tissue healing?
May accelerate healing of vascular & pressure ulcers
What effect does ultrasound have on tendon & ligament injures?
Reported to reduce tendon inflammation & to assist in healing of tendon & ligament after surgical incision
Is ultrasound supported for neck pain?
No
Is ultrasound supported for hip pain, mobility deficits, OA?
Moderate recommendation but therapeutic exercise is better
Is ultrasound supported for heel pain?
No
What is phonophoresis?
Use of ultrasound to promote transdermal drug delivery
How does phonophoresis work?
Works by increasing permeability of stratum corneum through cavitation
Once applied through skin the meds becomes systemic due to vascular network
What medication is used with phonophoresis?
Used to deliver a corticosteroid anti-inflammatory medication (dexamethasone) for inflammatory conditions
Can phonophoresis be useful when using an NSAID or corticosteroid?
More useful with NSAID but not as effective as with a corticosteroid
What are the advantages of phonophoresis?
-Safe
-Non invasive
- Painless
- Avoids GI tract (no 1st pass or GI irritation)
- Can apply to specific area
What are contraindications for ultrasound?
- Malignant Tumor
- Pregnancy
- Over central nervous system tissue
- Total joint replacement
- Pacemaker (within 6 months)
- Thrombophlebitis
- Over the eye
- Over the reproductive organ
What are the precautions to ultrasound?
- Acute Inflammation
- Epiphyseal plates
- Fractures
- Breast Implants
What are some adverse effects to ultrasounds?
Burn
Cross Contamination
How can you prevent someone from being burned with ultrasound?
Always move ultrasound head
Do not apply thermal ultrasound to areas of impaired circulation or sensation
What is the application technique for using ultrasound?
- Evaluate patient clinical finding & goals of treatment
- Determine whether ultrasound is appropriate
- Check Contraindication & precautions
- Apply US transmission medium to area to be treated
- Select a sound head with ERA approx half the size of treatment area
- Select parameters
- Wipe sound head w/ alcohol prep pad
- Place sound head on treatment area
- Turn on ultrasound machine
- Move sound head within treatment area
- Remove everything
- Reassess patient for changes
- Document
When wanting to apply heat to superficial tissue what frequency should you use of ultrasound?
3MHz
When wanting to apply heat to deep tissue what frequency should use of ultrasound?
1MHz
What is the duty cycle when wanting to get a thermal effect with ultrasound?
100% continuous
What is the duty cycle when wanting to get non-thermal effect with ultrasound?
20-50% pulsed
