Transcript TENS Lecture

T.E.N.S.
Trancutaneous Electrical Nerve
Stimulation
General Concepts:
• An Approach to pain control
– Trancutaneous Electrical Nerve Stimulation:
– Any stimulation in which a current is applied
across the skin to stimulate nerves
– 1965 Gate Control Theory created a great
popularity of TENS
– TENS has 50-80% efficacy rate
– TENS stimulates afferent sensory fibers to elicit
production of neurohumneral substances such
as endorphins, enkephalins and serotonin (i.e.
gate theory)
TENS
• Indications
– Control Chronic Pain
– Management postsurgical pain
– Reduction of posttraumatic & acute pain
• Precautions
– Can mask underlying
pain
– Burns or skin irritation
– prolonged use may
result in muscle
spasm/soreness
– caffeine intake may
reduce effectiveness
– Narcotics decrease
effectiveness
TENS may be:
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high voltage
interferential
acuscope
low voltage AC stimulator
classical portable TENS unit
Biophysical Effects
• Primary use is to control pain through Gate
Control Theory
• May produce muscle contractions
• Various methods
– High TENS (Activate A-delta fibers)
– Low TENS (release of -endorphins from
pituitary)
– Brief-Intense TENS (noxious stimulation to
active C fibers)
Techniques of TENS application:
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Conventional or High Frequency
Acupuncture or Low Frequency
Brief Intense
Burst Mode
Modulated
Protocol for Various Methods of
TENS
Parameter
High TENS
Low TENS
Intensity
Sensory
Motor
Brief-Intense
TENS
Noxious
Pulse Fq
60-100 pps
2-4 pps
Variable
Pulse
Duration
Mode
60-100 sec 150-250 sec
Modulated
Tx Duration
As needed
Modulated
Burst
30 min
Onset of
Relief
< 10 min
20-40 min
300-1000sec
Modluated
<15 min
15-30 min
Conventional Tens/High
Frequency TENS
• Paresthesia is created without motor
response
• A Beta filers are stimulated to SG enkephlin
interneuron (pure gate theory)
• Creates the fastest relief of all techniques
• Applied 30 minutes to 24 hours
• relief is short lives (45 sec 1/2 life)
• May stop the pain-spasms cycle
Application of High TENS
• Pulse rate: high 75-100 Hz (generally 80),
constant
• Pulse width: narrow, less than 300 mSec
generally 60 microSec
• Intensity: comfortable to tolerance
Set up:
• 2 to 4 electrodes, often will be placed on
post-op. Readjust parameters after response
has been established. Turn on the intensity
to a strong stimulation. Increase the pulse
width and ask if the stimulation is getting
wider (if deeper=good, if stronger...use
shorter width)
Low Frequency/Acupuncture-like
TENS:
• Level III pain relief, A delta fibers get Beta
endorphins
• Longer lasting pain relief but slower to start
• Application
– pulse rate low 1-5ppx (below 10)
– Pulse width: 200-300 microSec
– Intensity: strong you want rhythmical
contractions within the patient’s tolerance
Burst Mode TENS
– Carrier frequency is at a certain rate with a built
in duty cycle
– Similar to low frequency TENS
– Carrier frequency of 70-100 Hz packaged in
bursts of about 7 bursts per second
– Pulses within burst can vary
– Burst frequency is 1-5 bursts per second
– Strong contraction at lower frequencies
– Combines efficacy of low rate TENS with the
comfort of conventional TENS
Burst Mode TENS - Application
• Pulse width: high 100-200 microSec
• Pulse rate: 70-100 pps modulated to 1-5
burst/sec
• Intensity: strong but comfortable
• treatment length: 20-60 minutes
Brief, Intense TENS: hyperstimulation analgesia
– Stimulates C fibers for level II pain control
(PAG etc.)
– Similar to high frequency TENS
– Highest rate (100 Hz), 200 mSec pulse width
intensity to a very strong but tolerable level
– Treatment time is only 15 minutes, if no relief
then treat again after 2-3 minutes
– Mono or biphasic current give a “bee sting”
sensation
– Utilize motor, trigger or acupuncture points.
Brief Intense TENS - Application
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Pulse width: as high as possible
Pulse rate: depends on the type of stimulator
Intensity: as high as tolerated
Duration: 15 minutes with conventional
TENS unit. Locus stimulator is advocated
for this treatment type, treatment time is 30
seconds per point.
Locus point stimulator
• Locus (point) stimulators treatment occurs
once per day generally 8 points per session
– Auricular points are often utilized
• Treat distal to proximal
• Allow three treatment trails before efficacy
is determined
• Use first then try other modalities
Modulated Stimulation:
• Keeps tissues reactive so no
accommodation occurs
• Simultaneous modulation of amplitude and
pulse width
• As amplitude is decreased, pulse width is
automatically increased to deliver more
consistent energy per pulse
• Rate can also be modulated
Electrode Placement:
• May be over the painful sites, dermatomes,
myotomes, trigger points, acupuncture
points or spinal nerve roots.
• May be crossed or uncrossed (horizontal or
vertical
Contraindications:
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Demand pacemakers
over carotid sinuses
Pregnancy
Cerebral vascular disorders (stroke patients)
Over the chest if patient has any cardiac
condition