high frequency current Flashcards
what is the freq of a HFC
100,000 and above
describe HFC
Anti inflammatory effect d/2 endogenous heat(w/in tissues)
Molecules w/in tissues have +ve / -ve polarity
Electrodes attract oppositely charged molecules
The attraction causes molecular vibz-> endogenous heat
what are the effects of endogenous heat
Longer lasting
Stim reticuloendothelial system and anti inflam cells
No effect on thermoregulatory centre and CV
what are the two types of HFC
D’arsonoval and microwaves (decimetric and centrimetric currents(
d’arsonoval current wavelenth
2000/3000m
d’arsonoval current
freq
200-300khz
what type of current is d’arsonoval
alternating
how is the d’arsonoval current applied
Applicator is a glass electrode. Sltn w/in turns pink/blue when current is generated
what effect does the magnetic component of d’arsonoval curretns have
general
what effect does the electric component of d’arsonoval curretns have
local. w/ 3 types of effects
1. distant effect
2. contact effect
3. analgesic effect
distant effect of d’arsonoval currents
increased distance has increased iritative and anti itching effects and burning effects
contact effect of d’arsonoval currents
glass electrode in close contact w/ skin. Longitudinally moved along vessels or concentric movements. Pin prick sensation
Analgesic effect of d’arsonoval currents
d/2 sim of Abeta nerve fibers that inhibit nociception
how is the d’arsonoval current generated
Charge both plates
Energy travels to self inductive coil
Once fully charged the energy returns to the plates
This stims endogenous heat and anti inflam effect
indications for d’arsonoval current
Hair loss
Cosmetics
Stimulation of circ
Renal diseases
Buergers disease
Slow healing wounds - stimulates skin regeneration
CVD pt -e.g. Ist stage arterial hypertension
Bactericidal effect- high temp stims leukocytes
contraindications of d’arsonoval currents
- metal implants
- low and medium freq currents
Decimetric and centrimetric currents (microwaves)
structure
-vley charged cathode in centre
Resonating cavities are several circuits
This causes oscillation of electrons w/in the cavities and they accelerate
apposite acceleration causes electron migration towards the applicator(glass rod)
define diathermy
production of heat in a part of the body by high-frequency electric currents, to stimulate the circulation, relieve pain, destroy unhealthy tissue, or cause bleeding vessels to clot.
effect of diathermy w/ 1 celsius increase
anti inflamm. Increase metabolism
effect of diathermy w/ 2-3celsius increase
analgesia, reduce muscle spasm
effect of diathermy w/ 3-4 celsius increase
promotes collagen extensibility
Short wave diathermy: freq
27.12 megahz
Short wave diathermy: current type
sinusoidal currents
Short wave diathermy: application
magnetic field or electric current
Short wave diathermy:wavelength =
11.06m
Short wave diathermy: dose
pt subjective
diathermy rx for acute pain
athermal and oligothermal rx
diathermy rx for chronic pain
thermal and hyperthermal rx
types of diathermy electrode meters
capcitive and inductive
what does the capacitive electrode meter do
Electrical
Stimulates endo heat in tissues w/ increased resistance e.g. bone, brain, fat
what does the inductive electrode meter do
Magnetic
Used for tissues containing liquid e.g. lymph, blood vessels
why does d’arsonovalization generate the least amount of endo heat out of all the HFC
The fading d’arsonoval wave
