TENS Flashcards
What is TENS used for
Pain relief / pain modulation
What is TENS
Transcutaneous Electrical Nerve Stimulation (TENS)
Application of pulsed electrical current over the skin to stimulate analgesia by stimulating/depolarizing nerve fibers for pain modulation
What type of current is TENS
Pulsed current
Waveform involved in TENS
Biphasic wave:
- symmetrical
- asymmetrical (balanced)
TENS current can be delivered in single pulses or _____________.
BURSTS of pulses
What is meant by pulse frequency?
Range?
Unit ?
Types?
The number of pulses delivered per second
Range: 1 - 200 Hz
Unit: Hz (pps)
Types of frequency:
- HIGH ( acute pain )
- LOW (chronic pain )
Range for current amplitude in TENS
Between 0 and 120 mA
Range of pulse duration in TENS
Ranges from 50 - 400 ΞΌs
What is burst duration
What is interburst duration
What is burst frequency
The time from the beginning and the termination of one burst
The duration between two bursts
The number of bursts per second (1- 10 bursts/sec)
(NOTE: each burst consists of 5-10 pulses)
What makes TENS very comfortable
TENS devices are CC-type stimulators , meaning current amplitude remains constant (no surge)
What are the 5 modes on TENS
Conventional
Acupuncture
Burst train
Brief intense
Modulated
What are the two most common TENS used
Conventional (most common)
Acupuncture
Conventional is used for what kind of pain
ACUTE pain
Acupuncture is used for what kind of pain
CHRONIC pain
Pulse duration (pulse width) of Conventional VS Acupuncture
Conventional : SHORT pulse duration ( < 150 ms)
Acupuncture: LONG pulse duration ( > 150 ms)
Pulse rate (frequency) of Conventional VS Acupuncture
Conventional : HIGH frequency ( > 80 Hz)
Acupuncture: LOW frequency ( < 80 Hz)
Current amplitude (intensity) of Conventional VS Acupuncture
Conventional :
- comfortable
- sensory stimulation
Acupuncture:
- comfortable/tolerable
- sensory + motor stimulation ( muscle twitching is ok)
Proposed mechanism for pain relief of Conventional VS Acupuncture
Conventional : Gate theory
Acupuncture: Endogenous opiates descending pain suppression system
Target nerve fibers of Conventional VS Acupuncture
Conventional:
- Large A Ξeta sensory afferent mechanoreceptors
Acupuncture:
- A alpha
- Large A Beta
- Small A Delta
- C pain fibers
Sensation of Conventional VS Acupuncture
Conventional:
- comfortable
- pins and needles
- tingling
- minimal or no muscle contractions
Acupuncture:
- tingling with muscle contraction
Onset of analgesia in Conventional VS Acupuncture
Conventional: Rapid within minutes ( up to 5 minutes)
Acupuncture: Slow within hours (starts after 15 minutes)
Time of treatment of Conventional VS Acupuncture
Conventional: minutes or hours
Acupuncture: < 60 minutes
Length of pain relief of Conventional VS Acupuncture
Conventional: short lasting analgesia ( < few hours)
Acupuncture: long lasting analgesia (> few hours)
What is burst train TENS
Sensation ?
Target nerve fibers?
Mechanism of pain relief?
Onset of pain relief?
Length of pain relief ?
Time of application?
Delivery of low frequency bursts with current amplitude that stimulates BOTH sensory AND motor (similar to acupuncture)
Tingling + moderate muscle contractions
A delta , motor alpha, and C fibers
Mechanism: opiate system
Slow onset within hours
Long lasting analgesia
15-60 minutes of application
What is brief intense TENS?
High or low frequency?
Short or long pulse duration?
Low or high current amplitude ?
Target nerve fibers?
Mechanism of pain relief ?
Sensation ?
Onset of analgesia ?
Length of analgesia ?
Time of application ?
When is it used?
Delivery of electrical pulses with LONG durations, HIGH frequency, and current amplitudes capable of NOXIOUS stimulation
High frequency ( > 80 Hz)
Long pulse duration ( > 150 ms)
High current amplitude at noxious level
Target nerves: A beta, A delta, and C nerve fibers
Mechanism: opiate system
Sensation: muscle contraction + maximum tolerable pain
Onset: Rapid within minutes
Length of analgesia: long lasting
Application time: LESS than 15 minutes
Used before painful procedures
What is modulated TENS
What does it prevent
Pulse duration, frequency, and amplitude are randomly modulated at the same time during therapy
Prevents nerve adaptations
What determines which mode should be used when more than one is applicable ?
Based on trial and error and patient comfort
Which mode of TENS is the most comfortable
Conventional
Electrodes sizes, shapes, and types
Sizes :
-Small (localized small area
-Large (distributed larger area / less risk of damage)
Shapes : Square, rectangular, or round
Types:
- carbon impregnated (best conductor)
- Silicon rubber electrodes (+ electroconductive gel)
- Self adhesive
- Sterile electrodes for postoperative pain
How are electrodes attached?
Surgical tape
Self adhesive electrodes
Straps
What is the Coupling medium ?
Gel or water
Electrode maintenance is done by
Frequent visual inspections
Periodic measurement of electrode impedance
Why should the electrode be completely covered with gel besides optimizing conduction ?
To prevent burn which can occur because the current will be condensed in the area with little gel
TENS channel units
TENS indications:
General contraindications for TENS (hint: 7)
Impaired mentation ( discomfort/burn)
Epileptic patient ( inducing epileptic episode)
Thoracic region ( affect heart function)
Cervical region ( vagus/phrenic stimulation + carotid sinuses = hypotension + laryngeal spasm)
Cranial region ( affect brain function)
Malignant areas (metastasis)
Cardiac pacemaker / defibrillator (risk of interference)
Local contraindications of TENS ( hint: 5)
Impaired sensation ( discomfort/pain)
Back, abdomen, pelvic regions of pregnant woman in FIRST TRIMESTER or menstruating woman ( induces labor / risk of bleeding)
Damaged skin ( severe pain)
Metal implants ( overheating)
Hemorrhagic areas ( increase bleeding)
Electrode placement includes :
Within or around the area of pain
Spinal cord segment
General limb pain
Over specific body points ( trigger points)
Treatment time
What happens with inadequate time ?
Low rate : 20 -30 minutes
High rate: 10 minutes to several hours
Inadequate time = failure and poor pain relief
True or false
We cannot use TENS on a pregnant woman in her second/third trimester or even during labor
False
It is only a contraindication in her FIRST trimester
Advantages of TENS
Sources of poor results
