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ECS II - Direct Current Modalities (High Volt/Ionto)

Terms in this set (56)

What factor does Direct Current bring that alternating current does not?
polarity
What is direct current?
continuous unidirectional flow of charged particles
Red lead =
anode
Anode is (+/-)
positive
Red lead/Anode attracts ____________ ions
negative
Red lead/Anode ___________________ muscle excitability (increase/decrease)
decreases
Red lead/Anode leads to ______________ formation
(acid/base)
acid
Red lead/Anode used for ________ healing (wound/bone)
wound
Black lead =
cathode
Cathode is (+/-)
negative
Black lead/Cathode attracts _____________ ions
positive
Black lead/Cathode _______________ nerve excitability (increases/decreases)
increases
Black lead/Cathode leads to __________ formation (acid/base)
base
Black lead/Cathode used for __________ healing (wound/bone)
bone
Pneumonic to remember what the cathode is
Black lead
Base formation
Bone healing
How is the circuit completed with direct current?
skin completes the circuit
Major dangers of direct current
1. injury can be caused at low amplitude
2. acidic or alkaline reactions can occur in the skin at low amplitude (5 mA)
3. significant tissue damage is possible
Benefits of E-stim
1. prevent muscle atrophy
2. prevent fibrotic changes in muscle
3. prevent venous stasis
4. facilitate re-innervation in peripheral nerve injuries
Risks of E-stim
1. disrupt regenerating nerve fibers
2. muscle is very sensitive to trauma
3. no strong evidence to support long term benefits
4. D/C stim on someone with sensory compromise
What are the pulse durations required for High Volt?
extremely short - 2-50 microseconds
T/F higher current is needed to produce physiologic effects from High Volt
false, lower current
What does the wave form look like for High Volt?
twin peak, monophasic, pulsed current
What is High Volt typically used for?
in response to tissue injury (wound healing, pain relief)
Describe High Volt in terms of pulses, pulse duration, and interphase pulse direction
paired pulses
very short pulse duration
long interphase between paired pulses
3 phase of healing
1. inflammatory
2. migration
3. proliferation
What is galvanotaxis?
the attraction of specific cells to an electric charge
What is tissue polarity based on?
the sodium pump
Which is more negative: the surface of the skin or deeper tissues under the skin?
surface of the skin is more negative
What is the current of injury theory?
-tissue polarity reverses following an injury
-positive polarity triggers the onset of the repair process
T/F positive polarity is present in chronic wounds
false, the positive polarity is transient and is absent in chronic wounds
What type of stimulation (anodal vs. cathodal) would you use to amplify the "current of injury" theory?
Anode stimulation - positive polarity

theoretically (and shown via studies) this will accelerate wound healing of an acute wound
What are the 2 primary theories related to e-stim increasing circulation?
1. activation of autonomic nerves
2. pumping of muscle contraction
How many pps are necessary to induce increased circulation via rhythmic muscle contractions?
16 pps were able to produce change

no change with stimuli at 2 or 4 pps
What type of stimulation (anodal vs. cathodal) would you use to produce bacteriostatic effects?
cathodal stimulation - negative polarity
T/F there are significant differences between gram positive and gram negative in terms of response to cathodal stimulation
false
When should you change polarity when treating an infected wound?
after cultures show that the wound is clear of infection
3 effects of e-stim for wound healing with High Volt
1. replicates & accelerates "current of injury"
2. increases circulation (increases nutrients available for healing)
3. kills bacteria preventing wound healing
How long are typical wound healing treatment sessions with High Volt?
at least 1 hour long
What two mechanisms are responsible for edema reduction via High Volt e-stim?
1. noncontractile (sensory level)
2. contractile (motor level)
T/F there is good evidence for noncontractile e-stim for edema reduction
false
What is the mechanism that is thought to reduce edema when using high volt noncontractile e-stim?
thought to involve repelling the large (hydrophyllic) polar molecules released by trauma in the current path
How does contractile e-stim for edema reduction work?
reproduces normal venous/lymphatic return by rhythmically contracting and relaxing agonist and antagonist muscle groups (muscle pump)
Indications for High Volt
1. wound healing
2. edema reduction
3. pain control (less common)
What is Iontophoresis?
a technique which uses electric stimulation to drive free ions of chemicals with medical value across permeable membranes
What is required for a PT to use iontophoresis?
MD prescription for "ion" medication
T/F the repelling of like ions is enough to account for significant changes when using iontophoresis
false
How does iontophoresis work?
Hydrodynamic Pore Theory
-pore enlargement and new pore production allow for like ions to repel each other and drug is delivered through the skin
Describe the relationship between intensity and permeability when using iontophoresis
higher intensity = greater permeability
What type of current is required for iontophoresis?
continuous direct current
How is administration dosage of iontophoresis determined?
milliamp x minutes

higher intensity = less treatment time
What is the main advantage of iontophoresis?
noninvasive medication delivery for pain relief and/or inflammation
Iontophoresis for pain relief: (state ion polarity)
-lidocaine
-salisylate
-mecholyl
-lidocaine: positive
-salisylate: negative
-mecholyl: positive
Iontophoresis for inflammation: (state ion polarity)
-dexamethasone
-Citrate
-dexamethasone: positive or negative
-citrate: negative
What solution would you use to treat hyperhidrosis with iontophoresis?
water
Contraindications for iontophoresis
1. same as for e-stim
2. specific ion/drug allergies
Precautions for iontophoresis
use great care and monitor patients
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