shortwave diathermy chapter 9. description high-frequency electrical currents high-frequency...
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Shortwave Shortwave DiathermyDiathermy
Chapter 9Chapter 9
DescriptionDescription
High-frequency electrical currentsHigh-frequency electrical currents– Radio wavesRadio waves
Pass through the tissuesPass through the tissues Cause molecular vibrationCause molecular vibration Results in deep heatingResults in deep heating Capable of heating large volumes of Capable of heating large volumes of
tissuestissues Causes both thermal and nonthermal Causes both thermal and nonthermal
effectseffects
UsesUses
Thermal EffectsThermal Effects Deep heatDeep heat Increased blood Increased blood
flowflow Increased cell Increased cell
metabolismmetabolism Increased tissue Increased tissue
extensibilityextensibility Muscular relaxationMuscular relaxation Possible changes in Possible changes in
enzyme reactionsenzyme reactions
Nonthermal EffectsNonthermal Effects Edema reductionEdema reduction Lymphedema Lymphedema
reductionreduction Superficial wound Superficial wound
healinghealing Treatment of Treatment of
venous stasis venous stasis ulcersulcers
Types of Shortwave Types of Shortwave DiathermyDiathermy
Induction FieldInduction FieldCapacitive FieldCapacitive Field
Induction Field Induction Field DiathermyDiathermy
Places the patient in the Places the patient in the electromagnetic fieldelectromagnetic field
Selectively heats muscleSelectively heats muscle Also referred to as:Also referred to as:
– Condenser field diathermyCondenser field diathermy– Magnetic field diathermyMagnetic field diathermy
Induction Field Diathermy Induction Field Diathermy (Cont.)(Cont.)
A coil is housed within a A coil is housed within a drumdrum
Current flowing within Current flowing within the coil produces a the coil produces a rotating magnetic fieldrotating magnetic field
Magnetic field produces Magnetic field produces eddy currents in the eddy currents in the tissuestissues
Eddy currents cause Eddy currents cause friction that produce heatfriction that produce heat
Although rare, cables are Although rare, cables are sometimes used in place sometimes used in place of drumsof drums
Capacitive Field DiathermyCapacitive Field Diathermy
Uses the patient’s tissues as a part of the circuitUses the patient’s tissues as a part of the circuit The tissues’ electrical resistance produces heatThe tissues’ electrical resistance produces heat Selectively heats skinSelectively heats skin
– Muscle is heated via conduction from the adiposeMuscle is heated via conduction from the adipose Also referred to as “condenser field diathermy”Also referred to as “condenser field diathermy”
Capacitive Field Diathermy Capacitive Field Diathermy (Cont.)(Cont.)
Heat is produced by Heat is produced by the dipole effectthe dipole effect
Charge particles Charge particles within membrane within membrane align with the fieldalign with the field
The movement The movement produces heatproduces heat
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Modes of ApplicationModes of Application
ContinuousContinuous Increases tissue temperatureIncreases tissue temperature Increased risk of burnsIncreased risk of burns
PulsedPulsed May or may not increase temperatureMay or may not increase temperature Pulses allow for increased treatment Pulses allow for increased treatment
intensity and durationintensity and duration Not the same as “nonthermal”Not the same as “nonthermal”
Ultrasound & SWD Ultrasound & SWD Comparison Comparison
UltrasoundUltrasound Shortwave DiathermyShortwave DiathermyEnergy typeEnergy type AcousticalAcoustical ElectromagneticElectromagneticTissue heatedTissue heated Collage-richCollage-rich C: Skin, adipose tissueC: Skin, adipose tissue
I: Muscle, vesselsI: Muscle, vesselsTissue volumeTissue volume Small (20 cmSmall (20 cm22)) Large (200 cmLarge (200 cm22))Temp increaseTemp increase 1 MHz: > 6.31 MHz: > 6.3°°FF C: > 7C: > 7°°FF
3 MHz: > 14.93 MHz: > 14.9°°FF I: > 18I: > 18°°FFHeat retentionHeat retention 3 min3 min > 9 min> 9 min
C = Capacitive methodC = Capacitive methodI = Induction methodI = Induction method
Biophysical EffectsBiophysical Effects
InflammationInflammation Assists in removal of cellular debris Assists in removal of cellular debris
and toxinsand toxins Nonthermal:Nonthermal:
– Alters diffusion rate across the cell Alters diffusion rate across the cell membranemembrane
ThermalThermal– Increases intramuscular metabolismIncreases intramuscular metabolism
Biophysical EffectsBiophysical Effects
Blood and Fluid DynamicsBlood and Fluid Dynamics Vasodilation increases:Vasodilation increases:
– Blood flowBlood flow– Capillary filtrationCapillary filtration– Capillary pressureCapillary pressure– Oxygen perfusionOxygen perfusion
Increased fibroblastic activity and capillary Increased fibroblastic activity and capillary growthgrowth
Effects occur deeper than other forms of Effects occur deeper than other forms of heatheat
Biophysical EffectsBiophysical Effects
Tissue ElasticityTissue Elasticity SWD can vigorously heat deep SWD can vigorously heat deep
tissues tissues Alters collagen properties, allowing it Alters collagen properties, allowing it
to elongateto elongate Requires stretching during and/or Requires stretching during and/or
immediately following the treatmentimmediately following the treatment Multiple treatments are requiredMultiple treatments are required
Biophysical EffectsBiophysical Effects
Wound HealingWound Healing Nonthermal SWD increases rate of Nonthermal SWD increases rate of
phagocytosisphagocytosis Number of mature collage bundles Number of mature collage bundles
increaseincrease ATP activity increases (assisting ATP activity increases (assisting
wound regeneration)wound regeneration) Necrosed muscle fibers decreaseNecrosed muscle fibers decrease
ContraindicationsContraindications Metal implants or metal Metal implants or metal
jewelry (be aware of body jewelry (be aware of body piercings)piercings)
Cardiac pacemakersCardiac pacemakers Ischemic areasIschemic areas Peripheral vascular diseasePeripheral vascular disease Perspiration and moist Perspiration and moist
dressings: The water dressings: The water collects and concentrates collects and concentrates the heat.the heat.
Tendency to hemorrhage, Tendency to hemorrhage, including menstruation.including menstruation.
PregnancyPregnancy Fever Fever
Sensory lossSensory loss CancerCancer Areas of particular Areas of particular
sensitivity:sensitivity:– Epiphyseal plates in Epiphyseal plates in
childrenchildren– The genitalsThe genitals– Sites of infectionSites of infection– The abdomen with an The abdomen with an
implanted intrauterine implanted intrauterine device (IUD)device (IUD)
– The eyes and faceThe eyes and face– Application through the Application through the
skullskull