PTA 110 - Modalities Heat

What does Superficial heat produce

vasodilation in local cutaneous blood vessels and less in deeper vessels that run through muscles

What does Superficial heating agents stimulate

increased activity of the cutaneous thermoreceptors

Decreased sympathetic activity occurs which causes what

a decrease in smooth muscle contraction

When Decreased sympathetic activity occurs which causes a decrease in smooth muscle contraction, what does that result in

vasodilation at the site as well as distal extremities

Elevation of muscle temperature to 108F has been shown to result in a decreased firing rate of what muscle type

Type II muscle spindles

Elevation of muscle temperature to 108F has been shown to result in an increased firing of what fibers

1b fibers from GTO’s

What doeds Decreased muscle spindle activity results in

relaxation of muscle contraction

Heat has what kind of effect

gating

Heat has an immediate gating effect on the transmission of sensation of pain at what level

spinal cord

Muscle strength and endurance decreased how long after the application of heat

30 minutes

After application of heat, how long is recovery

around 2 hours

what must you be aware of when assessing muscle strength

when and if you applied heat

what does Increased tissue temperature increase

the amount of oxygen available for tissue repair

what happens when When soft tissue is heated

less force is required to achieve an increase in length, and thus less chance of tearing

List the uses of SUPERFICIAL heat

Pain control Gaiting of pain fibers Improved healing/decreased muscle spasm Psychological though that heat is comfortable INCREASED ROM Greater length in soft tissue is obtained and less injury occurs with passive stretch, Accelerated Healing Increases circulation and enzymatic activity rate and increases oxygen to the tissues Can be beneficial during the proliferative or remodeling stages of healing Infrared radiation for psoriasis Infrared radiation for dermal ulcers

Ultrasound maximizes energy absorption at a depth of what

2 to 5 cm of soft tissue

what is the Transducer:

Sound head

Intensity

power per unit area of the sound head

how is intensity expressed

watts/cm2

Power:

Amount of acoustic energy per unit time

How is power expressed

Watts

Beam Nonuniformity Ratio (BNR):

ratio of the peak intensity to the average intensity

Frequency:

number of cycles per unit time

How is frequency expressed

Hertz (Hz)

What does Increasing the frequency cause

a decrease in depth of penetration

Effective Radiating Area (ERA):

The area of the transducer from which the ultrasound energy radiates

What is the ERA smaller than

the treatment head

Absorption:

Conversion of the mechanical energy of ultrasound into heat

what does absorption depend on

tissue type and frequency

What has high absorption values

Tendons, cartilage, and bone

Attentuation:

: a measure of the decrease in ultrasound intensity as the wave travels through the tissue

Attentuation is higher for what tissue

dense that have high water content

Ultrasound Thermal Effects

increases the temperature of tissues up to 5cm deep

Ultrasound thermal therapy is usually aimed at what

joint capsules, and fascia

What is thermal ultrasound therapy effective for

pain management

when is thermal ultrasound therapy NOT used

acute phase of injury

when is ultrasound pulsed on and off

throughout the treatment

Pulsed Ultrasound allows circulation to get rid of what

any thermal heat during the “off time”

During pulsed ultrasound what are the mechanical effects that occur

increase in skin and cell membrane permeability, increased histamine release, increased rate of protein synthesis

Duty Cycle

the ratio of on time to off time

What are the Common duty cycles:

20, 50, and 100%

Most units have which duty cycle

20%

It has been shown that mechanical effects of pulsed ultrasound facilitate what

healing of dermal ulcers, surgical incision sites, tendon injuries, and bone fractures

When would there be a lower dose of intensity during thermal ultrasounds

for mechanical effects and acute conditions (.5 - 1.0)

When would there be a moderate dosage of intensity for thermal ultrasound

for thermal or mechanical effects and subacute conditions (1.0-1.5)

When would there be a higher dosage of intensity for thermal ultrasound

For thermal effects and chronic conditions (1.5-2.5)

What is the required duration for thermal ultrasound to achieve a physiological response

greater than 3 minutes

How long is the usual duration of thermal ultrasound

5-10 minutes

If you desire thermal effects using 1mhz, how long do you need to treat for

10 minutes

How often can you use thermal ultrasound

daily is okay

Sound waves produced by the transducer cannot travel through what

Air

what molecule can act as a coupling agent in plastic or metal container

water

What does water hold

sound

where does water hold sound

parallel to and about 1 inch from the area to be treated

what type of gel do you use on patients skin

conductive gel

Use conductive gel on the patient’s skin and maintain what

firm contact between the sound head and the patient throughout the course of treatment

what is water good use for

irregular surfaces

Why should you use extra .5watts/cm2 of water

to compensate for the absorption that takes place in the water

Superficial heating is negated by the

waters cooling effect, but deep heating still takes place

What to include in DOCUMENTATION

Patient position, Area treated, Transducer size, Frequency, Duty cycle, Pulsed vs. continuous, Intensity, Duration, Patient response to treatment

phonophoresis

Use of ultrasound waves to deliver a medication through the skin

It is hypothesized that what effects help deliver the medication

mechanical and thermal

Why must you Must be selective on what preparations are used

some will block the transmission of the US waves and negate the thermal effects

Ultrasound/E-stim Combo

combine treatment for a dual effect

What is the Ultrasound/E-stim Combo ideal for

spasm conditions