high voltage pulsating current
- 3. I HAFSA KHALID MARYAM KHALID LAIBA ROOP PAUL AQSA MUSHTAQ LAREB SATTAR SABIHA MANZOOR
- 5. Introduction HVPC used in therapy for many years in many countries. It is highly popular in other countries HVPC delivers monophasic current so the polarity of each electrode is known. It is a versatile form of electrical stimulation It has wide variety of uses (Muscle reeducation, nerve stimulation, Edema reduction, pain control)
- 6. HVPC generator produces: twin peaked waveform (pulses in duplets) OR a train of two single pulses having a short phase duration and long interpulse interval. Interpulse interval is much longer than pulse duration
- 7. Low pulse charge requires an output voltage of approx. 150 V or more to stimulate motor or sensory nerves i.e. high peaked voltage up to 500 V typically between 150-500 V Short phase duration allow activation of sensory and motor nerve at a low intensity without stimulating pain fibers.
- 8. Definition The high volt pulsed galvanic stimulator (HVPGS), a type of neuromuscular stimulator is a short duration (microsecond), microamperage current driven by a high voltage current (up to 300 volts) that is delivered as a twin-peak monophasic waveform of fixed duration (100 microseconds). This direct current can produce both a mechanical contraction and a chemical change within the body.
- 9. HVPGS is the use of a high driving voltage (up to 500V) to produce analgesia, muscle contractions, and to facilitate wound healing. Galvanic stimulation combines very short pulse duration (of constant intensity) and high peak voltage, yet low total current per second, to give relative comfort and avoid tissue damage while stimulating deep tissues. It is also an efficient means of exciting nerve fibers
- 10. Parameters Current type: (A) Direct current (B) Monophasic pulsed DC (C) Symmetric biphasic pulsed (D)Twin peak monophasic Amplitude: 0-500 ma Voltage: 150-500 Volts Pulse Frequency : 1-120 Pulse/sec Pulse Duration: 13-100 ms Phase Duration: 13-100 ms
- 11. (A) direct current (B) monophasic pulsed DC (C) symmetric biphasic pulsed (D)twin peak monophasic
- 12. Waveforms Saw tooth M-wave Square Wave
- 13. Treatment duration Typical duration of HVPC is 15-30 min and the treatment may repeated as many time as day needed
- 14. MODES: A MODE SWITCH CAN CHANGE THE PATTERNS OF CURRENT: 1. In continuous mode: The train of twin pulses are delivered continuously. 2. Reciprocate mode: Refers to the alternate application of train of pulses to one or other of two active pads and does not mean that current direction is reversed 3. Surge mode: Gives a train of pulses whose intensity is gradually increased
- 15. Physiological effects Maintaining or increasing range of motion. Re-educating muscles. Edema/swelling/inflammation reduction. Reducing motor spasticity. Increasing local blood circulation to injured area and promoting fluid movement to and from treatment area.
- 16. Preventing or retarding muscle disuse atrophy. Managing chronic/post-traumatic/post- surgical pain conditions allowing patient to participate in their pain management program. Stimulation and acceleration of wound healing by promoting blood circulation to wound.
- 17. Uses 1. Wound healing 2. Muscle Stimulation 3. Edema Reduction 4. Reduction of muscles spasm 5. Pain modulation
- 18. 1. Wound healing This current is formed to cause healing of the wound and ulcer. Induce human fibroblast Increase rate of DNA and protein synthesis Hence healing occurs
- 19. Positive electrode is used as active electrode if wound healing is free from infection. This is because of the biophysical effects on wound healing are polarity specific. Blood clots /infection pH acidic (+) Hence cathode is used
- 20. To account for the effects of polarity during the treatment of cutaneous wounds the application of 20 min of negative polarity by 14 min of positive polarity stimulation has been recommended .
- 21. • NOTE: depending upon the polarity of electrode leucocytes, epidermal cells, fibroblast are attracted to the area and level of collagenase increases. • HVPS inhibits the growth of bacteria in infected wounds. • No changes in Ph and temperature that could effect wound healing are not seen.
- 22. Negative polarity helps in dissolving blood clots and increases inflammatory byproducts, promoting healing of the tissues.
- 23. 2. Muscle stimulation The current is used for stimulation of innervated muscle as the pulses are very short(short pulses at high intensity are more selective in stimulating motor rather than pain nerves). HVPS is used both for strengthening as well as reduction of disuse atrophy. Frequency of 30 Hz has been used.
- 24. 3. Edema reduction Rhythmical muscle contraction and release due to the HVPS on motor nerve produces a pumping effect and increased blood flow in muscle and tissues and helps in draining in edema and direct effect on the ANS leads to local vasodilation, increase fluid exchange thereby reduces edema .
- 25. 4. Reduction of spasm Ability of HVPS to stimulate innervated muscle has leads to recommendation of this current in the treatment of muscle spasm and enhance joint mobility.
- 26. 5. Pain modulation Mechanism of pain relief brought about by this current is the same as involved in the gate control theory of pain. Since both the frequencies and intensities of HVPS can be controlled. It is possible to apply both the high frequency and low intensity stimulation for pain gate control and low frequency or high intensity stimulation for opiate release in descending pain suppression