Physical Agents Flashcards
T/F: Hot packs and paraffin are examples of convection physical agents in the transfer of heat.
false, conduction
- heat transfer froma warmer object to cooler object by means of direct interaction
- convection = movement of air/fluid from a warmer area to a cooler area
What are the physiological effects of general heat application? (BP, etc)
aka whirlpool
decreased BP Increased vasodilation decreased stroke volume increased cardiac output increased HR
What is cardiac output determined by?
CO = HR x SV
What fibers are inhibited through local heat application? (think gait theory of pain)
A delta and C fibers inhibited
- via activation of A beta fibers (gait theory)
How does heat reduce muscle spasm?
decreased afferent firing of muscle spindle (aka communication that muscle is stretched) and increased firing of GTO fibers (inhibiting fibers) that reduce alpha motor neutron activity
How many towels should be between a patient and a hot pack?
6-8 layers
Why would you administer paraffin?
- pts with chronic inflammatory condition (arthritis)
- joint stiffness
What are contraindications to paraffin?
open wound, allergic rash, recent scars/sutures, skin infections
What are contraindications to the use of superficial thermotherapy?
acute inflammatory condition, decreased circulation, DVT, impaired cognition, malignant tumor, decreased sensation
T/F: Whirlpool should be used for wound management.
false
T/F: Pregnancy is a contraindication for using heat.
false, just a precaution
Why does edema result from local/general heat application?
causes increased capillary permeability so fluid leaks into interstitial space
T/F: Cardiac output and stroke volume both decrease with use of cryotherapy.
false, both increase
T/F: Hypertension is a precaution to cryotherapy.
true, not a contraindication
T/F: It’s a precaution to use cryotherapy over regenerating nerves, like at the end of a residual limb.
false, contraindication: shouldn’t use cold over regenerating peripheral nerves
You are about to give an ice massage to your patient’s lateral epicondylitis. What will you explain to them about what they feel, in order?
cold, burning, aching, then numbness
When doing ice massage, what should you be sure not to massage over?
bony prominence superficial nerve (peroneal)
Your patient has peripheral vascular disease and requests use of a cold pack for their back. What do you tell them?
It’s contraindicated, sorry bud
- it will constrict your vessels even more leaving you ischemic
What is vapocoolant spray typically used for?
used for reducing muscle spasm, desensitize trigger points
What should be done to the muscle while applying vapocoolant spray?
passive stretch
- then have pt perform active exercise after spraying
What are contraindications of cryotherapy?
PVD, cold hypersensitivity, raynauds, over regenerating peripheral nerves, paroxysmal cold hemoglobinuria
What are contraindications of thermotherapy?
acute/early subacute inflammatory conditions, decreased circulation, DVT, impaired cognition, malignant tumor, decreased sensation
For a patient with an acute issue that’s swelling and all that, how long would you tell them to ice it?
ice for 20min on, 20 min off
- body vasodilates to prevent “loss” of body part from the vasoconstriction you’re doing
When might you use a contrast bath with a patient?
anytime stimulation of peripheral limb circulation is indicated
- PVD, sprains/strains, trauma (after acutity of situation is down)
What are contraindications to use of contrast bath?
advanced atherosclerosis
loss of sensation to heat/cold
arterial insufficiency
T/F: Continuous ultrasound provides thermal effects.
true
- pulsed US = NO thermal effects
How can you mitigate the effects that occur from the US intensity not being uniformly distributed over the transducer?
moving soundhead
go to pulsed US
When might pulsed US be more desired than continuous?
for acute soft tissue injuries where you’ve still got inflammation and don’t want to add heat to the mix
What is the Beam nonuniformity ratio for ultrasound? (BNR) Why is it important?
BNR = ratio of spatial peak intensity to spatial average intensity
- lower the BRN, the more uniform the energy distribution, so decreased risk of tissue damage
What is the duty cycle set at for pulsed US?
<50%
- 100% or close to that is continuous US
T/F: It’s a precaution to use US over healing fractures or breast implants.
true
- precaution: breast implants, healing fractures, acute inflammation, open epiphyses
At the 1MHz level, this is able to hit what kind of structures, deep or superficial?
deep
- superficial structures hit at 3MHz
For TMJ to reduce chronic pain, what settings for duty cycle and frequency would you want?
frequency: 3MHz (since superficial)
duty cycle: close to 100% so it’s continuous for the heat
Should you use US on the back of a patient that’s had a laminectomy?
absolutely not b/c potential cavitations
- contraindication to do US over unprotected spinal cord
How large should your treatment field be for US?
2x the transducer head
What would the purpose of using pulsed ultrasound be?
1) improve rate of healing
- increased circulation, increased rate of fibroblast synthesis for tissue repair, increase macrophage activity, increase cell membrane permeability to dec. swelling
2)
Can you use US in the back of a pregnant woman?
no
- nor uterus, pelvic, abdomen area (duh)
What does the treatment intensity value look like for ultrasound?
.5-2.5 w/cm^2
- lower intensity for superficial
- higher intensity for thicker tissue (low back)
If a patient complains of periosteal pain during an ultrasound treatment, what parameter should you change?
intensity: lower it (remember normal is .5-2.5)
also make sure you’re adequately moving the transducer
How long is typical treatment time for US?
3-10min
What are contraindications to short wave diathermy?
pregnancy pacemakers any implanted device (insulin pump) metal, including jewelry malignancy
What are the thermal vs nonthermal benefits of SWD?
thermal: increased joint ROM, pain management, increased tissue healing
nonthermal: pain control, decreased edema, resolution of acute/chronic infections, wound control, soft tissue healing
What should you watch for in the environment when giving SWD to make sure everyone in the environment is safe?
- have those with metal implants, pacemakers, pregnancy all steer clear
- should make sure obese pt isn’t getting SWD since their fat may heat excessively
