E-Stim Flashcards
What is electricity?
is the force created by an imbalance in the # of electrons at 2 points, aka poles
what is polarity?
refers to net charge of an object
How does a charge travel?
by the path of least resistance
What is voltage?
the force of attraction or repulsion created by an electric field, greater the force the greater potential energy
What are the ions in our body?
sodium, potassium and chloride. the more ions present the greater electric potential
What are good conductors of electricity in the body?
water, nerves, muscle, body fluids
What are not good conductors?
adipose tissue
What is current?
rate of flow of electricity in response to voltage
What us Ohm’s Law?
Current (I)= voltage/ resistance
more resistance to current the less current or flow there will be
How can we decrease resistance of skin?
clean area with alcohol swab, heat area if cold, optimal electrode placement
Does a smaller or larger electrode have greater current density?
smaller area, higher the current density the more intense the effects
What are three types of e-stim currents?
- Direct Current (ionto)
- Alternating Current (IFC and Russian)
- Pulsatile Current (mono or biphasic)- can either be direct or alternating
Which type of current is most commonly used for modalities?
pulsed
What is direct current?
continuous unidirectional flow of charged ions for atleast one second
What are important things to remember with DC?
it has a known polarity like with ionto
the body is given no break so the pt is at risk for a burn
What is AC?
continuous bi directional flow of ions and must change direction at least one time per second
no polarity as electrons are constantly moving
What is a monophasic pulsed current?
interrupted uni directional flow of ions, even though there is a known polarity this setting is usually more comfortable
used a lot for wound care
What is a biphasic current?
interrupted bi directional flow of current, alternating btwn positive and negative
What are three components or biphasic
- Symmetrical vs Asymmetrical
- Balanced vs Unbalanced
- Shape of phase
Why is PC preferred to DC for muscle strengthening?
bc of the pulses the muscle is able to contract and relax due to depolarization
DC will only contract muscle once and not repolarize it
What is pulse duration?
time from start to end of all phases of a pulse
stimulus must be long enough for depolarization for ions to change
longer duration tends to decrease comfort
What are three time dependent characteristics?
phase and pulse duration and interpulse interval
What are the 3 excitatory phases produced by estim?
sensory, motor and pain
In order to reach motor reaction more comfortably what should PT do?
increase phase duration before intensity
What are desired duration levels for each response?
20-100 usec- sensory
200-400 motor
400-1000 noxious
What is a sensory level response to estim?
pins and needles feeling due to stimulation of A beta fibers
What is a motor level response to estim?
muscle tetany to twitch to full muscle contraction
A alpha nerve fibers
What is a noxious level response to estim?
elicits perception of pain, A delta and C fibers
What is the main amplitude characteristic?
intensity- measure of magnitude of current or voltage
Which type of wave form is reported as most comfortable?
symmetrical biphasic
Which waveform is preferred to stimulate large muscle groups?
symmetrical biphasic, most like an AP
T/F: All wave forms are capable of reaching peripheral nerves?
True
Which waveform poses least risk for skin reaction?
symmetrical biphasic
Which wave form is best for wound healing?
monophasic
What is pulse frequency?
number of pulses in a second, defines the quality of muscle response
What is desired frequency for Sensory TENS?
80-120 pps
What is desired frequency for motor tens ?
2-4 PPS
What is desired frequency for noxious tens?
2-4 or 50-150 pps
What is desired frequency for muscle re-ed?
30-75 pps
What are two ways to prevent accommodation?
vary frequency- sweep
vary intensity- scan
Under cathode or anode will depolarization happen more easily?
cathode, this is bc nerve is positively charged on outside and neg. on inside so nerve will be more excitable with cathode and less with anode
In what order do nerves depolarize?
sensory, motor, pain and muscle fiber
What are the three types of pain nerve fibers?
A, B, C
What are A fibers?
large, myelinated, fast condutcing
What are a-alpha fibers?
for proprioception and somatic (voluntary) motor
What are a beta fibers?
touch and pressure
What are a gamma fibers?
motor to muscle spindles
What are a delta fibers?
pain, temp and touch
What are B fibers?
small, myleinated, conduct less rapidly
What are c fibers?
smallest, unmyleinated and slowest
- dorsal root- pain, reflex response
- sympathetic- post ganglionic sympathetic
What type of fiber type is myleinated pain receptors?
a delta, felt most with ionto
What type of fiber type is unmyleinated pain receptors?
c fibers, need hogher intensity and duration
What is the pain transmission path?
some type of stimulus activates nociceptor
- neuron - spinal cord
- dorsal horn of spinal cord-ascending spinal thalamic tract
- tract to thalamus/sensory cortex
What is gait control theory?
brain can only receive so many pains signals, therefore to control nerve impulses to brain the worst pain wins
What is descending pain control?
opiate mediated, natural pain control
endorphins are released to help control pain
prob wont work w/ someone with opioid addiction
What are different types of endorphins?
short acting- enkephlans
long acting- serotonin, dopamine
Why is cardiac pacemaker/ arrhytmias a contraindication for estim?
effects ions for cardiac muscle
How does placement of pads effect deepness of penetration?
further away the two electrodes the farther deeper it goes but will also require greater intensity
What are the main uses for estim?
- muscle strength/activation
- muscle retraining (motor control)
- pain control
- increase circulation
- decrease edema
- increase tissue healing
What is TENS?
transcutaneous electrical nerve stimulation
usually biphasic symmetrical- more comfortable
biphasic asymmetrical- better for accomodation
no polarity
What are three types of TENS?
sensory, motor, noxious
What is sensory tens mostly used for?
acute pain management using gait control theory, short acting enkephalins
What is motor level tens mostly used for?
chronic pain or long lasting relief, produces muscle twitch to help relieve muscle spasms
What is noxious tens mostly used for?
rarely used but for severe pain, wound debridement and trigger points
short cuts pain loop and brain can only feel this pain
What is monophasic pulsed estim used for?
pain control, wound healing (great option), edema reduction (muscle pump), muscle facilitation
known polarity, quick so not as much is felt
What is BMAC?
burst modulated alternating current or russian
burst provides great depolarization
What is important for pt to do after russian tx session?
do volitional contractions to enhance neuromuscular affect
How many reps should pt perform with russian?
10? not too many as all muscle fibers fire causing muscle to fatigue faster
What is IFC?
interferential current, alternating currents of different frequencies that interfere with eachother
What is IFC used for?
used for pain modulation, acute chronic and muscle spasms
greater depth of penetration and covers large area
What are two different types of frequencies with IFC?
- Carrier- usually at 4000 hz
2. beat- diff of two frequencies
What is unique about electrode set up?
always use 4 electrodes so 2 currents intersect each other
quadpolar
What is a FES?
functional estim used for muscle re ed
for functional and purposeful movement
What frequency used with FES?
20-60 pps to induce contraction but not too hard to decrease fatigue
What is NMES?
neuromuscular education, used for muscle strengthening through improvement of motor recruitment
What are advantages on NMES?
symmetrical biphasic so less skin irritation
phase duration, pulse frequency, amplitude and duty cycle can all be manipulated
What else is NMES used for?
ROM, prevention of joint contracture, prevention of disuse atrophy
can be used when limb immobilized to slow onset of atrophy
might be better than russian for elderly as less intense
What are precautions when using NMES?
intense or prolonged session can produce soreness
avoid placement over tendon injury as it can pull tendon off bone, avoid where bony attachment is not secure
What is important to remember for monopolar set up?
there is only one single active electrode, smaller pad is active and has higher current density
Why is estim good for wound managment?
bc the estim attracts neutrophils, macrophages. lymphocytes
For debridement what cells are recruited and what is polarity?
macrophages and neutrophils, anode
infection?
active neutrophils, anode or cathode to attract active neutrophils
Granulation?
fibroblasts, cathode
wound contraction?
myofibroblasts, cathode
epitheliazation?
keritinocytes and epidermal cells, cathode
What should we document with estim?
- type of waveform
- waveform parameters
- electrode placement, size etc.
- patient position
- dosage
- treatment duration
- pain pre and post?
