E-stim basics – Flashcards

1. Creates muscle contraction through nerve or muscle stimulation (mm. re-education - manage tone and decreased strength) 2. Stimulate sensory nerves to modulate pain 3. Stimulate or alter the healing process 4. Create a electrical field to drive ions through the skin to enhance the healing process

Cathodes = Cations (+ charge) Anodes = Anions (- charge)

the rate at which current flows; for e-stim, usually described with therapeutic modalities in milliamperes

Established by the movement of ions (move from areas of higher concentrations to areas of lower concentrations). based on its own electric charge and its relative position to other electrically charged objects. (electric potentials cause voltage - ? - relationship btw electrical potential and voltage - nicole)

is an electromotive force that results from the accumulation of electrons at one point in an electrical circuit thus there is a difference in electron population between two points which causes a charge and a force (voltage is the force)

Low Volt < (100-150 V) < Hi Volt

Milliamps - rate of current flow or Volts - force generated from electrical potentials

is the ability of electrons to move freely through a pathway high conductance = current flows easy/freely/unrestricted

1. voltage applied 2. conduction characteristics of the material

opposition to electron flow. measured in ohms higher resistance will have less amps current flow=voltage/resistance (ohm's law)

1. Material composition 2. Length (greater length yields greater resistance) 3. Temperature (increased temperature, increase resistance)

Conductance is a measure of how well an artefact (such as an electrical component, not a material, such as iron) carries an electric current. Resistance is a measure of how well an artefact resists an electric current. They have an inverse relationship Conductance v. resistance = current permittance v. inhibition

electrical power watts=volts x amperes; indicates the rate at which electrical power is being used (its a measurement of rate or power? - nicole)

nicole? - Electrical potential results in charge and voltage?

1. administering medicinal drugs topically via iontophoresis 2. attempting to artificially fire a denervated muscle

Root mean squared (RMS) - is the average intensity (nicole) RMS is a statistical measure of the magnitude of a varying quantity.

1. pulse amplitude 2. pulse duration 3. waveform

DC: has more net charge over time thus causing a thermal effect AC: Zero net charge (ZNC) (nicole - unless it's current flow is asymmetric)

DC

The ability of a material (ex: tissue) to store electricity for a given current intensity and pulse duration

the longer before a response

Nerve (will fire first, if healthy) Muscle fiber Muscle tissue (mm. fiber is singular) Muscle membrane has 10x the capacitance of nerve

Increase intensity decrease pulse duration

DC's polarity is constant, where AC's polarity constantly reverses

uninterrupted unidirectional flow toward positive pole

continuous (uninterrupted - nicole) changes direction w/ changes in polarity move from negative to positive (nicole- doesn't the polarity determine the charge the current flows toward?)

DC = square wave AC = sine wave

pulsed and interrupted current are the same except pulsed has a shorter time connotation (fractions of a sec.) than interrupted (sec.'s)

pulsed/interrupted currents --> (mfac) and ifc

pulse

a pulse may contain more than one phase phase = polarity? (nicole)

I. Direct current: a. monophasic (single phase in each pulse) b. unidirectional (current flows in the same direction either toward the positive or negative pole) II. Alternating current: a. biphasic (two separate phases during each individual pulse) b. current flow reverses direction during each pulse (or phase? - nicole) i. may be symmetric or asymmetric; asymmetric builds a charge within the tissue III. Pulsed current: a. polyphasic (conducted as a series of pulses of short duration, followed by an interpulse interval (period of rest)) b. may be DC or AC but will always have interruption in current flow

Intensity of the current higher amplitude = increased penetrating ability; how far it penetrates is also dependent on tissue treated (diff. tissues have diff. absorption characteristics) Max amplitude = highest point of each phase

tot. amt. of electricity being delivered to pt. during each pulse

length of time current is flowing in one cycle phase & pulse duration determine which tissue is stimulated (if too short there will be no action potential)

rise = time to max peak decay = time from peak to zero

if variable, accommodation decreases rapid rising pulses cause nerve depolarization slow rising pulses cause nerve accommodation to stimulus and action potential is not elicited. Slow rise is used for reeducating muscle w/ assisted contraction - ramping (shock of current is reduced)

phases per second (measured in Hz, cycles/sec, pulses/sec)

no, b/c pulse frequency pertains to individual phases (affects phase duration not pulse duration)

decreases/increases more rapidly

1K Hz and below MENS (micro current) .1-1K Hz mm. stim units

1K Hz to 100K Hz Interferential, Russian stim, LVGS

above 100K Hz TENS, HVGS, Diathermies)

alteration of magnitude or duration of pulses helps prevent body from accommodating to stimulus

amplitude of current flow remains the same for seconds or minutes acidic or alkaline (medical galvanism) elicit mm. contraction and iontophoresis

current flows for some period of time, and is turned off sine, rectangular, or triangular waveforms either mm. reeducation and improved ROM loger time of interruption w/ interrupted as apposed to burst/pulse

aka pulse train Pulsed current flows for a short period and turned off in a short period mm. effect is negligible due to short nature of pulse break all of the above

current builds gradually to a max amplitude makes for more comfortable mm. reeducation

blood bone

cause movement of ions longitudinally than transversely no

6 x's

Amplitude: must be high enough so that depolarization of the membrane will occur Rate of change of voltage: must be sufficiently rapid so that accommodation does not occur Duration of the individual stimulus: must be long enough so that the time course of the latent period (capacitance), action potential, and recovery can take place (nicole?)

ensure grounding and intactness of power cord do not use extension cords look out for water inspect annually (remove defective equipment immediately)

Do not do the following: DO NOT apply to the thoracic area (or transthoracically) of a patient with arrhythmia, congestive heart failure, recent myocardial infarction, and other heart conditions 2. DO NOT apply anywhere on the body of a patient with a demand-type implanted cardiac pacemaker or defibrillator or deep brain stimulator 3. DO NOT apply through the carotid sinus area (at the bifurcation of the common carotid artery); it may cause a rise in blood pressure, reflex vasodilatation and slow the heart rate. 4. DO NOT apply transcerebrally (thru the head) at a milliamp level because it may cause changes in brainwave patterns.EXCEPTION Microcurrent can be applied transcerebrally. 6. DO NOT apply through cancerous (malignant) tissue. 7. DO NOT apply through areas of broken or irritated skin. The current flows through breaks in the skin, causing discomfort. Exception: (This is different from using electrical stimulation for wound healing.) 8. DO NOT apply near or touching protruding metal such as surgical surface staples or external pins because they are excellent conductors of electricity. 9. DO NOT use on any patient who reacts very negatively to the experience or to the sensation of stimulation. 10. DO NOT apply to a patient with undiagnosed pain. 11. DO NOT apply to patients who cannot provide adequate feedback concerning the level of stimulation (infants, individuals with mental disorders).

Use caution with: Precautions (Be Cautious) 1. USE CAUTION in applying at high amplitude directly over areas where bone is superficial. Periosteal pain can result. 2. USE CAUTION when applying in areas of excessive adipose tissue since the high levels of stimulation necessary to activate underlying structures may cause pain or autonomic reactions 3. USE CAUTION in applying within 3 feet of a transmitting cellular phone or two-way radio. This may cause electrotherapy equipment malfunction. (airplane mode) 4 USE CAUTION in applying near the uterus during pregnancy and delivery. (The possible effects on a fetus is not known.) 5 USE CAUTION in applying within 10 feet of Group 2 ISM equipment that generates high frequency or high energy electromagnetic radiation. Such equipment includes welding or cutting equipment, diathermy units & surgical electrocautery units. This may cause electrotherapy equipment malfunction. 6. USE CAUTION when applying in the region of the urinary bladder because the current may interfere with normal function 7. USE CAUTION when applying over scar tissue because the scar will have an increased electrical resistance. The current will preferentially travel around the scar causing increased current density at the edges of the scar with possible burning. 8. Use caution in applying to a patient with history of metastatic disease. 9. Use caution in a patient with poor sensation.

the largest possible (decreases current density) for mm. or tissue treated w/o targeting adjacent mm./tissue size and location of the mm. or tissue to be treated determines the electrode size and configuration large electrodes w/ low resistance will produce more comfortable stimulation

by keeping them clean, and by keeping the gel hydrated If electrode gel appears to be getting dry, moisten it w/ a few drops of water

minimum of 1 inch apart

mfac or ifc (nicole)

potential for tissue damage

increased size of electrode and distance between electrodes electrodes closer than 1 inch can cause conduction at the edges of the electrodes, increasing the potential for burns

considering the frequency of the waveform. Higher frequency waveform will penetrate tissues better (will meet less resistance) Want to make the electrode resistance less than that of the tissue (doesn't this depend on how deep you want to penetrate nicole?) lower the resistance (higher the frequency), the lower the voltage needed to achieve the same therapeutic effect

the higher the resistance of some electrodes (nicole)

hydrogel (to decrease tack of the electrode)

increase the comfort of the tx. but also increase resistance and need for higher output intensities (wouldn't that make tx less comfortable? - nicole)

1. inspect for breaks 2. Cleanse w/ mild soap and water (also hydrates) a. do not use alcohol wipes b/c they dry skin and increase tissue resistance 3. shave if really hairy

5-8x's Mark the electrode pouch after each use to keep track

Electrodes placed close together will give a superficial stimulation and be of high density Electrodes spaced far apart will penetrate more deeply with less current density

increasing size of electrode decreases current density. Large pads may have areas of disproportionately high current concentration, which will functionally reduce the size of the electrode

1. Short Acting Pain Management: brief intense tens, sensory types of e-stim (produce no muscle contraction), high rate TENS, uses gate theory 2. Long Acting Pain Management: low rate tens, interferential with muscle contraction, want to activate endogenous opioid system 3. Acute Pain: use of sensory e-stim for gate theory 4. Chronic Pain: use of motor e-stim for endorphin/enkephalin release (endogenous opioid system), electroacupuncture, burst mode tens

manage pain by decreasing edema and managing inflammation

1. near the spine 2. near the area of pain 3. several spinal segments more proximal than segmental innervation (nicole?)

place four electrodes that bombard localized area of pain (ex: hip or knee)

1. Low tone: functional electrical stimulation, patterned e-stim, mfac 2. Muscle strengthening: mfac with a contraction ratio of 1:3-5 3. Hypertonia: mfac with a contraction ratio of 1:1 or 1:2 for full muscle fatigue, or on antagonist in 1:3-5; also works with muscle spasm in this ratio 4. Denervated muscle—continuous d/c, however mixed results in the literature

proximal

the least resistance to current and improve strength of contraction w/ decreased current intensity (what are motor points nicole?)

1. high volt pulsed current 2. microcurrent

1. MFAC—uses muscle contraction to pump edema out of the extremity 2. Biphasic—utilizes muscle contraction to enable increased edema movement with equal on/off time 3. HVPC—helps control tissue inflammation and therefore edema 4. Iontophoresis—helps to move an antinflammatory agent across the tissues through electrical current