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Electrical Stimulation. Clinical Application. High Volt Pulsed Stimulation. Amplitude: 0 to 500 mA Voltage : 0 to 500V Pulse frequency: 1-120 pps Pulse duration: 13 to 100 µ sec Phase duration : 20 to 45 µ sec . Adjustable Parameters Duty cycle Electrode alternating rate
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Electrical Stimulation Clinical Application
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 Adjustable Parameters Duty cycle Electrode alternating rate Electrode balance Intensity Polarity Probe electrode Surge/Ramp Parameters Current: Monophasic
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
Reeducation of peripheral nerves Delay of denervation and disuse atrophy by stimulating muscle contractions Reduction of post-traumatic edema Increase in local blood circulation (unsubstantiated) Restoring range of motion: Reduction of muscle spasm Inhibition of spasticity Reeducation of partially denervated muscle Facilitation of voluntary motor function Uses
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
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.
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
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.
Total current flow0 to 100 mA Pulse frequency1 to 150 pps Pulse duration 10 to 500 µsec Phase duration 5 to 250 µsec Adjustable Parameters Intensity Mode (output modulation) Pulse duration Pulse frequency Parameters Current: Biphasic
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
Uses • Control of acute or chronic pain • Management of postsurgical pain • Reduction of post-traumatic acute pain
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
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
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
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
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 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 Parameters Current: Alternating Two alternating currents form a single interference current. Premodulated output is based on a single alternating current.
Theory Carrier Wave Interference Wave • 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 = Variable Wave
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
Uses • Acute pain • Chronic pain • Muscle spasm
Effects • Pain Control • Similar to TENS • Most frequently used for motor-level pain control • Muscle Contractions • Neuromuscular re-education • Edema reduction
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
Total current: 0 to 200 mA Pulse frequency:1 to 200 pps Phase duration:20 to 300 µsec Intrapulse interval:Appx. 100 µsec Adjustable Parameters Intensity Pulses per second Duty cycle Reciprocal rate Ramp Parameters Current: Biphasic, Premodulated
Theory • Current type varies by manufacturer • Tends to have long phase duration • Biphasic and alternating current decreases possibility of electrode irritation
Uses • Maintaining range of motion • Muscle reeducation • Prevention of joint contractures • Prevention of disuse atrophy • Increasing local blood flow • Decreasing muscle spasm
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
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
Total current:Up to 5 mA Voltage: 80 V Dosage: 0 to 80 mA/min Adjustable Parameters: Dosage: Amperage Duration Polarity Parameters Current: Direct
Theory • The charges associated with a DC can “drive” medications into the tissue • Medication must have an electrical charge • Negative charges driven from the cathodeAttracted towards the anode • And vice-versa • Requires specialized electrodes to hold the medication
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
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
Sample Medications Medication Pathology Concentration Dosage Polarity Acetic acid Myositis ossificans 2% 80 mA/Min Negative Dexamethason Inflammation 4mg Decadron 41 mA/Min Negative and lidocaine Pain control 4% Xylocaine 40 mA/Min Positive Lidocaine and Pain control 4% Lidocaine 30 mA/Min Positive epinephrine 0.01 mL/1:50,000 30 mA/Min Positive Dexamethasone Inflammation 2cc 4mg/mL 41 mA/Min Negative Refer to the prescription for the exact treatment parameters. Each electrode size has a maximum treatment amperage. Consult the packaginginformation included with the electrodes.
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
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 Adjustable Parameters: Intensity Polarity/alternating polarity Ramp Threshold – Ohm Meter Parameters Current: Monophasic. Polarity reverses.
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.
Acute and chronic pain Acute and chronic inflammation Reduction of edema Sprains Strains Contusions Temporomandibular joint dysfunction Carpal tunnel syndrome Superficial wound healing Scar tissue Neuropathies Uses* * Efficacy has not been established
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.