intro to electrotherapy - part 1 Flashcards
what is charge
when electrons that is lost or gained become ions
a charge can either be _____ or _____
cation (+)
anion (-)
unit of measurement for charge
coulomb
what is current
movement of charged particles; opposite the flow of electrons
current is also referred to as _____ or _____
intensity or amplitude
standard unit for current
ampre or 1 C/sec
what is voltage
driving force that makes charged particles move
standard unit of volts
V or mV in our use
other name for voltage
electromotive force or electric potential difference
what is resistance
opposition to the movement of DC
standard unit of resistance
ohm
explain ohm’s law
V = IR
so current is directly proportional to voltage and indirect to resistance
what is conductance
ease of flow so opposite of resistance
standard unit for conductance
Mho or Siemens
what is capacitance
ability to store charge using electrostatic field
charge/voltage
standard unit for capacitance
Farad
what is inductance
ability to store electrical energy via electromagnetic filed
standard unit for inductance
Henry
what is impedance
opposition to movement of AC
standard unit for impedance
Ohm
compare battery and plug as a power source
battery - portable but needs spare batt and has limited options
plug - more stable and more options for control but not portable
what are the 3 main parts of an electrical stimulator
power source
waveform generation and timing control
output amplifier
what is constant voltage
voltage level will remain the same and will have low internal resistance
what is constant current
will change the voltage output but the leaving current is unaffected and will have high internal resistance
output impedance for constant voltage
< 50 ohm
output impedance for constant current
> 10k ohm
advantages and disadvantages of constant voltage
adv - automatic reduction of current when electrode size is reduced due to dec contact w skin
dis - risk for intensity of elec burns if pressure bet tissue and electrode is inc due to dec in tissue impedance; hence bawal HMP while TENS
advantages and disadvantages of constant current
adv - more consistent level of stimulation
dis - dec in electrode size due to inadequate contact will result in elec burns bcs it gets concentrated on part in contact w skin
betw constant current and voltage which is responsible for bringing physiological changes
constant current bcs it is more constant kaya eto din mas ginagamit sa clinic
anode vs cathode in terms of what it attracts
anode - anions
cathode - cations
anode vs cathode in terms of what it repels
anode - cations
cathode - anions
anode vs cathode in terms of what it forms
anode - acidic; fewer bubbles of o2
cathode - alkaline; many tiny bubbles of H
anode vs cathode in terms of color
anode - red
cathode - black
anode vs cathode in terms of effects on nerve
anode - dec nerve excitability d/t hyperpol
cathode - inc nerve excitability d/t depol
anode vs cathode in terms of type of electrode
anode - indifferent electrode
cathode - active electrode
anode vs cathode in terms of effect
anode - sedative
cathode - stimulative
anode vs cathode in terms of effects on tissue
anode - hardening of tissue d/t solidification of proteins; sclerotic
cathode - softening of tissue d/t liquefaction of protein; sclerolytic
what are the usual materials for electrodes
carbon impregnated silicon rubber
what should be the qualities of electrode materials
capable of rex chemically
conductor
non-toxic
durable
flexible
what are the coupling media
tap water
gel
karaya gum
explain electrode coupling
electrodes should be coupled to tissue both mechanically and electrically to function properly
what body structures have tissue impedance
adipose tissue
bone
skin
what body structure has highest tissue impedance and why
skin - because of keratin and very little water present
give techniques to dec skin impedance
hydration - moist cotton ball
tissue warming - IRR
use of high voltage - HVPGC
higher frequency - IFC
mild abrasion - not rrly done
discuss the significance of current density
amount of current flow/unit area
so dapat lapat or if probe be cautious
discuss longitudinal vs transverse orientations
long - for muscle contraction; so sa origin and insertion banda
transverse - for long muscles - medial and lat side of muscle belly
orientation of electrodes for quads
diagonal longitudinal
what should the distance be betw a stimulating and dispersive electrode
wag dikit
if motor point stim - same side dapat yung dispersive; R face : R traps
what is monopolar technique
only the cathode is place over target area then the anode is place on other body part for dispersion
uses of monopolar technique
motor point stim
dermal ulcers
wound healing
edema
iontophoresis
what is bipolar technique
both electrodes are placed over target area
both electrodes are excitatory
uses of bipolar technique
muscle disuse atrophy
neuromuscular facilitation
ROM limitation
protective muscle spasm
circulatory disorders
pain
what are the contraindications
pacemakers
phrenic or bladder stimulators
carotid sinuses
thrombosis
over pregnant uterus
cancer
safety considerations on patient care
always explain the procedure
use extreme caution of pt that cant communicate
do not use w/in 3m of diathermy
do not use 2 electrical devices simultaneously
what are the safety considerations in electrotherapy
patient care
electric shock
machine appli
compare microshock and macroshock
micro - < 1000 uA
macro - > 1000 uA
physiologic effects of 1 mA
threshold for tingling sensation
physiologic effects of 16 mA
cannot release grip on electrical conductor d/t muscle contraction
physiologic effects of 50 mA
pain and possible fainting
physiologic effects of 100 mA - 3 A
ventricular fibrillations
physiologic effects of 6 A
sustained myocardial contraction
temporary respiratory paralysis
burns
safety consideration w machine setup
never cheater plugs and close to pipes
use GFCI’s and electrodes designed for the machine
safety consideration w machine operation
gradual inc of amplitude only when all parameters are set
in changing parameters lower the intensity first
turn knob to 0 before applying and when turning off
adjust amplitude during on time only
remove electrodes only when there is no more current
