PTE 722: exam 2

cryotherapy

a medical treatment that uses extreme cold to destroy abnormal tissue or relieve pain

• 5-8 mins of treatment time with cold pack

thermotherapy

a treatment modality that uses heat to relieve pain, improve circulation, and promote healing

list some examples of deep vs. superficial heating agents.

deep: ultrasound, diathermy

superficial: heat packs, infrared lamps

what are the four modes of heat transfer?

1. conduction: transfer through direct contact between objects

2. convection: transfer through the movement of a fluid (like air or liquid)

3. conversion: transfer depends on the power of energy source

4. radiation: transfer through electromagnetic waves

T or F: the greater the temperature difference between a heating/cooling agent and the body part it is applied to, the faster the rate of heat transfer.

T

what mode transfers heat faster than conduction within the same time period?

convection

what is a natural process that transfers heat via convection throughout our body?

circulation of blood

• example: vasodilation increases circulation rate —> increases tissue temp

what factors does the rate of tissue temperature depend on when using conversion heat transfer?

• size of area being treated

• size of the applicator

• efficiency of transmission from the applicator to the patient

• type of tissue being treated

T or F: when utilizing conversion transfers, it requires direct contact between the thermal agent and the tissue.

F; doesn’t require direct contact

• does require an intervening material to be a good transmitter of energy tho

what factors does the rate of tissue temperature depend on when using radiation heat transfer?

• intensity of radiation

• relative size of radiation source

• size of area being treated

• relative size of distance of the source from the treatment area

• size of angle of the radiation to tissue

T or F: 5 mins of icing could increase isometric strength.

T

why might a therapist utilize cryotherapy?

to control inflammation, edema, and/or pain in patients or to modify spasticity or to increase viscosity of blood

patients with _____ _____ enjoy cryotherapy because it manages their symptoms.

multiple sclerosis

list some contraindications of cryotherapy.

• cold hypersensitivity

• cold intolerance

• cryoglobulinemia

• over-regenerating peripheral nerves

• over an area with circulatory compromise

what are some precautions to note when using cryotherapy?

• applying over a superficial main branch of a nerve or over an open wound

• hypertension

• poor sensation or mentation

• with very old or very young patients

what is the most severe adverse affect of cryotherapy?

tissue death

• caused by prolonged vasoconstriction, ischemia, or thromboses in smaller vessels

temporary or permanent nerve damage can become an adverse effect of cryotherapy. what is the time frame to avoid nerve damage?

limit cold application to under 45 mins

what are the neural stages of sensation with cryotherapy?

1. cold

2. burning

3. aching

4. numbness

*CBAN

what temperature should cold packs be kept at?

0-5 degrees C or 32-41 degrees F

cold packs should be cooled for at least __ mins between uses and for __ hours or more before initial use.

30 mins

2 hours

T or F: ice packs provide more aggressive cooling than cold packs at the same temp.

T

• therefore more insulation should be used when applying ice packs

T or F: a therapist must keep an ice cup/popsicle moving when in contact with patient’s skin

T

what combination has been shown to control swelling, pain, or blood loss the best?

cold AND compression simultaneously

what is a controlled cold compression unit?

a sleeve wrapped around an injured area that alternately pumps cold water and air, with compression being applied by the intermittent inflation of air

what is the purpose of vapocoolant sprays?

to provide a counterirritant stimulus to the cutaneous thermal afferents overlaying muscles to cause a reflex reduction in motor neuron activity and thus a reduction in resistance to stretch

is vapocoolant applied in parallel strokes along the skin before OR after stretching the patient’s muscles?

immediately before

cold whirlpools

indicated in acute and subacute conditions in which exercise of the injured part during cold treatment is desired

contrast baths

used to treat subacute swelling, gravity-dependent swelling, and vasodilation-vasoconstriction response

what is the purpose of cryokinetics?

numb the injured part to the point of analgesia and then work toward achieving normal ROM though progressive exercises (should be pain-free concentrating on both flexibility and strength)

what are some reasons why a therapist would utilize superficial heat?

• pain control

• increased ROM

• decreased joint stiffness

• accelerate healing

list the contraindications for thermotherapy usage.

• recent or potential hemorrhage at site

• thrombophlebitis

• impaired sensation or mental ability

• malignant tumor at site

list a few examples of precautions for thermotherapy use.

• acute injury or inflammation

• pregnancy

• impaired circulation or poor thermal regulation (cardiac insufficiency)

• edema

• over an open wound

T or F: burns may occur if heat is applied where protective vasodilation cannot occur.

T

hot packs should be heated for at least __ mins between uses and for __ hours or more before initial use.

30 mins

2 hours

which tissues transfer heat well?

muscles, tissues high in collagen

• thickness of subcutaneous fat does not transfer heat well

when would a therapist use ice vs heat with a patient? (Dr. Robinson question)

• ice: injury occurred recently (inflammation)

• heat: injury occurred a while ago (stiff)

take note of patient’s preference too

a hydrocollator is a purpose-designed, thermostatically controlled water cabinet that stays on at all times. what temperature should the hot water be kept at?

between 70-75 degrees C or 158-167 degrees F

paraffin, fluidotherpay, and infrared lights also act as a heat modality. what are they?

paraffin: a warm, melted wax mixed with mineral oil that can be safely applied directly to skin as a heating modality

fluidotherpay: cabinet containing finely ground cellulose particles where heated air is circulated through through

infrared lights: emit electromagnetic radiation within the frequency range that gives rise to heat when absorbed by matter

what is ultrasound?

sound with a frequency greater than 20,000 cycles per second (beyond the hearing of humans)

list the types of diagnostic ultrasound

• echocardiography 5 MHz

• echocephalography 5 MHz

• doppler blood 5-10 MHZ

• obstetrical doppler 2.25 MHz

what are the characteristics that make up therapeutic ultrasounds?

• deeply penetrating modality that has thermal and non-thermal effects

• between 0.7-3.3 MHz

• maximizes energy absorption at a depth of 2-5 cm

T or F: ultrasound waves do not require a dense medium in which to travel

F; they need a dense medium, usually a gel-like substance

if no significant temperature increase arises from fat and skin when using an ultrasound, then what structures can be heated to a therapeutic range?

tissues high in collagen

• tendons, muscles, ligaments, joint capsules, meniscus, and cortical bones

the transducer is an important aspect of an ultrasound machine. why?

its where the electrical energy is converted to acoustic energy and is where the crystal is housed

what happens during the compression and rarefaction phases of a therapeutic ultrasound wave?

compression phase: positive pressure; tissue molecules in the wave’s path are compressed

rarefaction phase: negative pressure; tissue molecules in the wave’s path spread out more

when the compression and rarefaction occurs in the same direction that the wave is traveling, a ____ wave forms.

longitudinal

when the compression and rarefaction occurs in a right angled direction that the wave is traveling, a ____ wave forms.

shear

• shear waves tend to form at surfaces of bone (periosteum)

T or F: when a beam enters the body it is either transmitted, reflected, refracted, or absorbed.

T

what are the characteristics of an ultrasound beam?

• sound wave is collimated as it leaves the transducer but begins to diverge when it penetrates to deeper tissues

• larger diameter transducers produce a more collimated bean than smaller transducers

• the sound field intensity is very non-uniform near the transducer head —> “near field”

T or F: tissue with more blood supply will heat up faster through ultrasound than tissues with less blood supply. (Dr. Robinson question)

F; tissues with more blood supply will dissipate through blood stream

what happens when an ultrasound hits soft tissue or bone? (Dr. Robinson question)

reflects off

spatial average intensity

represents the amount of energy in a specific area; represented as W/cm²

spatial peak intensity

represents the maximum intensity point in the beam; located in the far field of the beam

beam non-uniformity ratio

the ratio between the spatial peak intensity and the spatial average intensity (ex: 4:1 = spatial peak is 4, spatial average is 1)

a 1:1 ratio is theoretically ideal for a BNR but clinically unattainable, so ratios up to ___ are acceptable.

8:1

what MHz are wave frequencies typically delivered?

1 or 3 MHz

• a 1 MHz beam is more collimated nad penetrates deeper than a 3 MHz beam

what’s the main difference between continuous ultrasound and pulsed ulstrasound?

continuous is used primarily for its thermal effects

pulsed is used for its non-thermal effects

how is ultrasound generated?

by the application of a high frequency alternating electrical current to the crystal in the transducer of an ultrasound unit

what are some examples of thermal effects when using an ultrasound?

• acceleration of metabolic rate

• control of pain and muscle spasm

• alteration of nerve conduction velocity

• increased circulation/altered blood flow and enzymatic activity

• increased soft tissue extensibility

T or F: to increase the total amount of heat delivered to the tissue the duration of ultrasound application and/or the average intensity of ultrasound application must be increased.

T

describe the frequency of ultrasound application.

1 MHz to heat tissues up to a depth of 5 cm

3 MHz to heat tissues up to a depth of 1-2 cm

T or F: 3 MHz ultrasound has a lower depth of penetration therefore the maximum temperature increase is lesser than 3-4 times.

F; greater by 3-4 times

what unknown variables make it difficult to predict the temperature increase of ultrasound absorption?

• thickness of each tissue layer

• amount of circulation

• distance of reflecting soft tissue/bone interfaces

law of Grotthus-Draper

as superficial tissues absorb more energy, less energy is transmitted to underlying tissues

what is used to determine the final ultrasound intensity?

the patient’s report of warmth

at what temperatures should an ultrasound be maintained to achieve a therapeutic effect?

40-45 degrees C for at least 5 mins

what factors does the degree of tissue temperature rising depend on?

• mode of application

• intensity and frequency of the output

• vascularity and type of tissue

• speed at which the sound head moves

thermal ultrasound chart

what are some examples of non-thermal effects when using an ultrasound?

• increased skin and cell membrane permeability

• increased mast cell degranulation

• increased chemotactic factor and histamine release

• increased responsiveness of macrophages

• increased rate of protein synthesis by fibroblasts

the non-thermal effects of ultrasound include cavitation (mechanical vibration) and acoustic micro-streaming. what do these effects do to cell membranes?

distort them causing deformation of tissue molecules

cavitation

term given to the expansion and contraction of the gas bubbles due to the compression and rarefaction phases of the ultrasound wave

what’s the difference between stable and unstable cavitation?

stable: the gas bubbles expand and contract without growing to critical size

unstable: the gas bubbles expand too far and suddenly collapse, resulting in increased pressure and temp

acoustic microstreaming

term describing the fluid movement in and around tissue cells caused by the ultrasound wave

T or F: the primary site of ultrasound interaction is the cell membrane where the destabilization of the membrane leads to increased permeability. From here, various ions nad molecules can diffuse into the cells where they precipitate secondary events.

T

what chemical has been studied due to its influence on circulation and stimulating effect on protein synthesis?

histamine

list some examples of non-thermal or mechanical effects of ultrasound.

• increased histamine release

• increased phagocytic activity of macrophages

• increased protein synthesis

• increased capillary density of ischemic tissue

• cell membrane alterations

what are some clinical applications of ultrasound?

• soft tissue shortening

• pain control

• dermal ulcers

• surgical skin incisions

• tendon injuries or bone fractures

list examples of contraindications for utilizing ultrasound.

• malignant tumor

• pregnancy

• joint cement

• pacemaker

• reproductive organs

what are the four precautions for utilizing ultrasound?

1. acute inflammation

2. epiphyseal plates

3. fractures

4. breast implants

what type of knee or hip replacement does a therapist not want to ultrasound? (Dr. Robinson question)

cemented plastic

describe the transducer (soundhead) movement during applicaiton?

slow strokes at 4cm/sec in a back and forth or circular movement while maintaining good contact on surface

what are the physical properties of electromagnetic radiation?

• composed of electric and magnetic fields that are oriented perpendicular to each other

• does not need a medium to travel through

• natural and manufactured sources

• categorized by frequency and wavelength (inversely proportional to each other)

what’s a key difference between low frequency and high frequency electromagnetic radiation (ER)?

low frequency: cannot break molecular bonds or produce ions

high frequency: can break molecular bonds and produce ions

how do you determine the intensity of ER?

its proportional to the energy output from the source and the inverse square of the distance of the source from the patient and to the cosin of the angle of incidence

T or F: intensity is greater when the source is close to the skin and parallel to the skin.

F; it must be perpendicular to skin

Arndt-Schulz law

a minimum stimulus is required to initiate a biological process, beyond a certain level, stronger stimuli will have less positive result, may cause damage

T or F: laser has no thermal affect.

T

what are the physical properties of ultraviolet radiation?

• frequency range of 7.5 × 1014-1015 Hz

• wavelength from 400-290 nm

• between x-ray and visible light

what are the factors that determine the physiological effects of UV radiation?

• influenced by wavelength and intensity

• size of area being treated

• thickness and pigmentation of skin

• duration

what are the effects of ultraviolet radiation?

• erythema production

• tanning

• epidural hyperplasia

• vitamin D synthesis

• bactericidal

______ and ______ are clinical indications for the use of UV.

1. psoriasis

2. wound healing

what are the contraindications for using UV radiation?

• irradiation of the eyes

• treating patients with skin cancer, pulmonary tuberculosis, cardiac, kidney, or liver disease, systemic lupus, erythematosis, and fever

what are the precautions for using UV radiation?

• photosensitizing medication use

• photosensitivity

• recent x-ray therapy

list the adverse effects UV radiation.

• burning

• premature aging of the skin

• carcinogenesis

• eye damage

what are the three physical properties of lasers?

1. coherence: all photons of laser light are the same wavelength and individual wavelengths are in phase with one another

2. monochromaticity: single defined wavelength

3. collimation: photons move in a parallel manner, with minimal divergence, conentrating a beam of light

how are lasers classified?

classified by the type of material between the two reflecting surfaces

• examples: crystal, gas, liquid, diode, or chemical

what does MED stand for?

minimal erythemal dose

• will be on test!

what is the proper time frame for MED’s treatment response? (Dr. Robinson question)

shows up within 8 hrs, disappears after 24 hrs

what are low level lasers?

considered a low-power laser or cold, soft laser

• good for treating tendon/ligament injury, arthritis, edema, ulcer and burn care

what are the clinical indications for using a low-level laser?

• wound and fracture healing

• musculoskeletal disorders

• pain management