Transcript Electrical Stimulation

Electrical Stimulation
Clinical Application
© 2005 – FA Davis
High Volt Pulsed Stimulation
© 2005 – FA Davis
Parameters
Current: Monophasic
Amplitude:
0 to 500 mA
Voltage:
0 to 500V
Pulse frequency: 1-120 pps
Pulse duration: 13 to 100
µsec
Phase duration: 20 to 45 µsec
© 2005 – FA Davis
Adjustable Parameters
• Duty cycle
• Electrode alternating rate
• Electrode balance
• Intensity
• Polarity
• Probe electrode
• Surge/Ramp
Theory
• Short-duration, high amplitude (voltage) pulses
can produce comfortable, moderate
contractions.
– Short phase duration targets sensory nerves and
motor nerves
– Wave form is modified to decrease total current to
improve comfort
• Each electrode has a known polarity
– May cause galvanic (ion) changes
– Short phase duration and long interpulse interval
probably negates any effect
© 2005 – FA Davis
Uses
• Reeducation of peripheral
nerves
• Delay of denervation and
disuse atrophy by
stimulating muscle
contractions
• Reduction of posttraumatic edema
• Increase in local blood
circulation
(unsubstantiated)
© 2005 – FA Davis
• Restoring range of
motion:
• Reduction of muscle
spasm
• Inhibition of spasticity
• Reeducation of partially
denervated muscle
• Facilitation of voluntary
motor function
Effects
• Neuromuscular Stimulation
– Moderate to strong muscle contractions
– Less torque production than NMES
• Pain Control
– Sensory-level (short-term)
– Motor-level
– Acute pain: Positive electrode over painful site
– Chronic pain: Negative electrode over site
© 2005 – FA Davis
Effects
• Edema Control
– Negative electrode may prevent the formation
of edema
– Causes the gaps between endothelial cells to
close, preventing leakage
• Edema Reduction
– Motor-level stimulation “milks” the venous and
lymphatic vessels.
© 2005 – FA Davis
Effects
• Blood Flow
– Associated with frequency and intensity of
muscle contraction
• Wound Healing
– Electrode polarity kills or repels different
microbes
– Assists healing and inhibits bacteria growth
– Direct current techniques are more effective
than HVPS
© 2005 – FA Davis
Notes and Precautions
• Motor-level stimulation can cause unwanted
tension on the muscle fibers, the tendons, or the
bony insertion.
• Muscle fatigue can occur if the duty cycle is too
high.
• Intense or prolonged stimulation may result in
muscle spasm and/or muscle soreness.
• Improper use can cause electrode burns or
irritation.
© 2005 – FA Davis
Transcutaneous Electrical
Nerve Stimulation
© 2005 – FA Davis
Parameters
Current: Biphasic
Total current flow
0 to 100 mA
Pulse frequency
1 to 150 pps
Pulse duration
10 to 500 µsec
Phase duration
5 to 250 µsec
© 2005 – FA Davis
Adjustable Parameters
• Intensity
• Mode (output modulation)
• Pulse duration
• Pulse frequency
Theory
• Adjustable phase durations specifically
target sensory, motor, and pain fibers
• Phase duration is matched with pulse
frequency to produce specific effects
• Biphasic form prevents net residual charge
© 2005 – FA Davis
Uses
• Control of acute or chronic pain
• Management of postsurgical pain
• Reduction of post-traumatic acute pain
© 2005 – FA Davis
Effects
• High – Frequency TENS (Sensory Level)
– Short phase duration (< 100 µsec)
– High pulse frequency (60 to 100+ pps)
– Sensory-level output
– Activates spinal gate
– Long-term treatment
• Output must be modulated to reduce
accommodation
© 2005 – FA Davis
Effects
• Low – Frequency TENS (Motor level)
– Long phase duration (150 to 250 µsec)
– Low pulse frequency (2 to 4 pps)
– Motor-level output
– Pituitary gland releases:
• ACTH
• β-lipotropin
– Causes the release of β-endorphin
• Binds to the A-beta and C fiber receptor sites
• Blocks the transmission of pain
© 2005 – FA Davis
Effects
• Brief – Intense TENS (Noxious level)
– Long phase duration (300 to 1,000 µsec)
– High pulse frequency (> 100 pps)
– Noxious-level output
• Very short treatment duration
– Creates a negative feedback loop in the CNS
• Theoretically “short circuits” the pain carrying loop
• Opiates inhibit the release of Substance P
– Blocks or reduces pain transmission
© 2005 – FA Davis
Notes and Precautions
• Do not use to treat pain of unknown origin
• TENS is a symptomatic treatment
• Improper use can result in electrode burns or
skin irritation.
• Intense or prolonged stimulation may result in
muscle spasm and/or muscle soreness.
• Intake of 200 mg or more of caffeine may reduce
the effectiveness of TENS
• Narcotics decrease the effectiveness of TENS
© 2005 – FA Davis
Interferrential Stimulation
© 2005 – FA Davis
Parameters
Current: Alternating
Two alternating currents form a single
interference current. Premodulated output is
based on a single alternating current.
Current:
1 to 100 mA
Current flow (RMS) 0 to 50 mA
Voltage:
0 to 200 V
Carrier Frequency:
Fixed at 2500 to 5000 Hz
Beat Frequency:
0 to 299 Hz
Sweep Frequency: 10 to 500 µsec
© 2005 – FA Davis
Adjustable Parameters
• Intensity
• Beat frequency – Analogous to the
number of cycles or pulses per
second
• Burst duty cycle – Bursts
separated by periods of no
stimulation (interburst interval)
• Interburst interval – Duration of
time between bursts
• Premodulation (e.g., Russian
Stimulation)
• Ramp
• Sweep – Variation in the beat
frequency; Set with a low value
and a high value
• Vector/Scan – Variation in current
intensity
Theory
Carrier Wave
Interference Wave
=
Variable Wave
© 2005 – FA Davis
• High-frequency waves easily overcome
skin resistance
• The two waves are slightly out of
frequency
• They cancel each other out and produce
a frequency of 1 to 299 Hz in the tissues
• Results in a comfortable stimulation
capable of depolarizing sensory and
motor nerves
Unique Terminology*
• Beat Frequency/Beat Pattern
– Difference between the carrier frequency and
variable frequency
– Analogous to pulses per second
• Sweep
– An increase and decrease in the beat
frequency
• Scan
– An increase and decrease in intensity
* Terminology also varies from manufacturer to manufacturer
© 2005 – FA Davis
Uses
• Acute pain
• Chronic pain
• Muscle spasm
© 2005 – FA Davis
Effects
• Pain Control
– Similar to TENS
– Most frequently used for motor-level pain
control
• Muscle Contractions
– Neuromuscular re-education
– Edema reduction
© 2005 – FA Davis
Notes and Precautions
• Do not use in the presence of unknown
pain or pain of central origin
• Can cause electrode burns, skin irritation
• Motor-level use can cause muscle spasm
or muscle soreness
© 2005 – FA Davis
Neuromuscular Electrical
Stimulation
© 2005 – FA Davis
Parameters
Current: Biphasic, Premodulated
Total current:
0 to 200 mA
Pulse frequency:
1 to 200 pps
Phase duration:
20 to 300 µsec
Intrapulse interval:
Appx. 100 µsec
© 2005 – FA Davis
Adjustable Parameters
• Intensity
• Pulses per second
• Duty cycle
• Reciprocal rate
• Ramp
Theory
• Current type varies by manufacturer
• Tends to have long phase duration
• Biphasic and alternating current decreases
possibility of electrode irritation
© 2005 – FA Davis
Uses
•
•
•
•
•
•
Maintaining range of motion
Muscle reeducation
Prevention of joint contractures
Prevention of disuse atrophy
Increasing local blood flow
Decreasing muscle spasm
© 2005 – FA Davis
Effects
• Can produce substantial muscular tension
• Capable of increasing strength
– Used when limb is immobolized
– Also slows the onset of atrophy
• Duty cycle is required to prevent fatigue
© 2005 – FA Davis
Notes and Precautions
• Improper use may result in electrode burns or
skin irritation
• Intense or prolonged stimulation may result in
muscle spasm and/or muscle soreness.
• An electrically induced contraction can generate
too much tension within the muscle
• Use caution:
– Musculotendinous lesions, the tension from the
contraction may injure the muscle or tendon fibers
– Cases where the muscle’s bony attachment is not
secure
© 2005 – FA Davis
Iontophoresis
© 2005 – FA Davis
Parameters
Current: Direct
Total current:
Up to 5 mA
Voltage: 80 V
Dosage:
0 to 80 mA/min
© 2005 – FA Davis
Adjustable Parameters:
• Dosage:
– Amperage
– Duration
• Polarity
Theory
• The charges associated with a DC can
“drive” medications into the tissue
• Medication must have an electrical charge
• Negative charges driven from the cathode
Attracted towards the anode
– And vice-versa
• Requires specialized electrodes to hold
the medication
© 2005 – FA Davis
Dose-Oriented Treatments
• Medications are delivered in mA/Min
– Milliamp Minutes
• Function of the amount of current times
the duration of the treatment:
– 5 mA applied for 20 minutes
• 5mA * 20 min = 100 mA/Min
– 4 mA applied for 25 minutes
• 4mA * 25 minutes = 100 mA/Min
© 2005 – FA Davis
Uses
• Delivers medication to the tissues to treat:
– Acute inflammation
– Chronic inflammation
– Arthritis
– Myositis ossificans
– Myofascial pain syndromes
– Delivering local anesthetics before injection or
other minor invasive procedures
– Hyperhidrosis
© 2005 – FA Davis
Sample Medications
Medication
Pathology
Acetic acid
Myositis ossificans 2%
80 mA/Min Negative
Dexamethason
and lidocaine
Inflammation
Pain control
4mg Decadron
4% Xylocaine
41 mA/Min Negative
40 mA/Min Positive
Lidocaine and
epinephrine
Pain control
4% Lidocaine
30 mA/Min Positive
0.01 mL/1:50,000 30 mA/Min Positive
Dexamethasone Inflammation
Concentration
2cc 4mg/mL
Dosage
Polarity
41 mA/Min Negative
Refer to the prescription for the exact treatment parameters.
Each electrode size has a maximum treatment amperage. Consult the packaging
information included with the electrodes.
© 2005 – FA Davis
Notes and Precautions
• Controlled medications require a physician’s
prescription:
– Each patient requires his/her own prescription
– Follow any notes or instructions provided by the pharmacist.
– State practice acts may further regulate the delivery of
iontophoresis.
• The exact medication dosage delivered is unknown.
• Erythema under the electrodes is common
• Too intense of a treatment dose can result in electrode
burns
• Do not reuse electrodes
– Medications remain, contaminating the electrode
© 2005 – FA Davis
Microcurrent
© 2005 – FA Davis
Parameters
Current: Monophasic.
Polarity reverses.
Total current flow:
1 to 999 uA (Peak current)
25 to 600 uA (RMS)
Pulse frequency:
0.1 to 1000 Hz
Pulse duration:
0.5 to 5000 µsec
Phase duration:
0.5 to 5000 µsec
© 2005 – FA Davis
Adjustable Parameters:
• Intensity
• Polarity/alternating
polarity
• Ramp
• Threshold – Ohm Meter
Theory
• Small, subsensory charges can affect the
function of healing tissues
• Injured tissues have a reversal of their normal
electrical charges (“injury potential”)
• MET attempts to normalize the electrical
potential
• Activation of ATP and increase ATP levels
• The efficacy of MET has not been substantiated.
© 2005 – FA Davis
Uses*
• Acute and chronic
pain
• Acute and chronic
inflammation
• Reduction of edema
• Sprains
• Strains
• Contusions
* Efficacy has not been established
© 2005 – FA Davis
• Temporomandibular
joint dysfunction
• Carpal tunnel
syndrome
• Superficial wound
healing
• Scar tissue
• Neuropathies
Notes and Precautions
• If the patient is dehydrated, nausea,
dizziness, and/or headaches may result.
• Electrical “shocks” may be reported by the
patient when MET is applied to scar
tissue.
– Caused by decreased electrical resistance.
© 2005 – FA Davis