E Stim Flashcards
where are electrodes contraindicated? (9)
- eyes
- carotid bodies
- trunk/heart with pacemakers
- pelvis/abdomen in pregnant women
- phrenic nerve stimulators
- gonads
- PVD areas
- active osteomyelitis sites
- hemorrhage areas
is a pacemaker a contraindication or precaution for stim?
trick question, it depends on the cardiac doc’s input
what are 6 precautions for estim
- non intact sensation
- pt w difficulty communicating
- compromised mental ability
- cardiac dysfunction
- seizures
- active or hx cancer
what three effects are produced by estim
thermal, physical, and chemical
why is it common to see redness under an electrode pad
heat and vasodilation
what can you do to decrease resistance to current flow?
ensure proper pad attachment by cleaning the area with soap and water and avoiding callused areas of skin
what is the electrophysical effect of estim (3 steps)
- cell membranes become more permeable to Na
- resting membrane potential decreases
- nerves depolarize first
describe cell charge at rest
net negative intracellular controlled by Na and K exchange
why do most individuals feel estim before seeing or feeling a motor response
the most superficial Aalpha and beta fibers depolarize first
do large or small diameter fibers depolarize easier?
small
as you increase amplitude and duration of estim, what are the three levels of response?
sensory > motor > pain
what is the force frequency relationship
as frequency increases, force increases
what are the five indications for estim
- skeletal muscle activation
- pain
- tissue healing
- edema
- improve blood flow
what are the three skeletal muscle estim
nmes, ems, fes
what is nmes?
stimulation of the nerve to cause a muscle contraction
what is ems?
stimulation of a denervated muscle
what is fes?
stimulating muscle (either innervated or denervated) to enhance functional movement
when is nmes indicated? (3)
- post ACL/TKA for quads
- CP/SCI/MS/stroke to enhance strength
- to decrease spasticity
how can nmes decrease spasticity? (3)
- reciprocal inhibition via antagonist
- to fatigue spastic muscle group
- sensory stim leading to habituation
is spasticity velocity dependent or independent? what does this mean?
velocity dependent: ramp up the antagonist slowly to overcome spasticity
what kind of stim is NMES
burst modulated AC (Russian or Aussie)
where are electrodes placed for NMES
over functional motor points (which don’t have to be known for the exam)
relatively, how do you set up NMES?
- set intensity and pulse duration as high as possible
is NMES different than a voluntary contraction?
yes, NMES is unorganized motor recruitment vs voluntary contractions which start with smaller units before bigger units
do tv abdominal stimulators meet NMES parameters?
no, they dont have the pulse or duration to cause hypertrophy
how does FES relate to NMES?
FES = NMES with functional activity
what are the three most common uses for FES?
shoulder subluxation, UE function after stroke/TBI/SCI, and DF assistance
what muscles would you target for FES indicated for shoulder subluxation?
supraspinatus to elevate the humeral head and post delt to posteriorly translate it
remark upon the parameters for FES
set the minimum necessary to elicit the desired effect to prevent fatigue
small or large pads for FES?
largest you can without stimulating antagonists
how is stimulating a denervated muscle different than NMES or FES?
it takes a higher charge and a pulse duration >10ms to stimulate the sarcolemma; also, there is not strong evidence to support its use
what are the nociceptors called
a-delta and c fibers
what does the a-delta fiber do (3)
first pain sensation, withdrawal reflex, and precise location of stimulus
what does the c-fiber do
second pain, prevents further tissue damage
what is the gate theory
a-beta fibers block noxious afferents
when is tens indicated
pain relief
what kind of estim is tens
biphasic pulsed
where are the top four places to place tens pads
- on/around painful area
- over dermatomes
- spinal cord segment innervating the area
- trigger points
any combination may also be used
how high do you set tens?
strongest comfortable paresthesia below muscle contraction
what is low frequency tens and how does it work
motor stimulation releases endogenous opioids
what are two drawbacks to low frequency tens?
- 15-45min duration of tx
2. cannot be used during activity b/c of muscle contraction
how does the stem pattern differ between tens, IFC, and NMES
IFC is crisscrossed
TENS and NMES is up and down
what kind of stim is IFC
amplitude modulated AC
how does IFC work
2 different sine waves interfere to create a beat frequency
what is the difference between IFC and PreMod
Premod is IFC but the beat frequency is already created in the machine so you only need two electrodes
what are the requirements for tissue healing stim?
- grade 3-4 pressure ulcer
2. no sign of healing for 30 days with standard care
what kind of stim is tissue healing?
high volt twin peak monophasic
how do you apply tissue healing stim?
direct to wound or region around it via saline moistened sterile gauze, inactive electrode 15-30 cm away
how high do you set the intensity for tissue healing?
strong tingling just below muscle twitch. if insensate then turn up to muscle twitch and then down until the twitch disappears
what type of stim is used for edema
high volt pulsed monophasic
how can stim be used for edema
only during the acute phase and below the motor threshold for 30 min on and 30 off for 3-4 hours
what kind of stim is iontophoresis
DC
what is the significance of the ionto pads
the closer the pads, the more superficial the current
how do you determine ionto dosage
dose = current x duration
