High Volt Pulsed Current (HVPC)

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High Volt Pulsed Current (HVPC)

• Almost 60 yrs old, popular last 25 years with
  numerous uses.
• Review of the waveform
• Twin-peak monophasic pulse
• phase duration 25?s, sometimes adjustable
• comfortable but weak current polarity present
  but electrochemical (net DC) effect not harmful.
  Typical stimulation time does not exceed 1 hour.

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Clinical Application

• Use Is the goal stimulation of the peripheral
  nerve OR some other tissue?
• For NMES PN stim is the goal best for mild to
  moderate contractions and areas not covered with
  excess adipose.
• For TENS - PN stim is the goal portable HVPC
  devices do exist
• Wound healing - chronic, slow healing wounds
• Acute edema formation based in animal research
• Iontophoresis - cutting edge not widely
  supported
• PN stim is NOT the goal on the last 3, but it
  still happens

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Factors in using HVPC for NMES or TENS

• Amplitude (based on desired excitatory response)
• Pulse Rate (related to pain control theory or
  motor response needed)
• Mode - Continuous, Ramp-Surge, Alternate
• Placement of Electrodes
• nothing new

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Wound Healing E-stim for Tissue Repair (ESTR)

• Robert Becker 1962
• Theory - Current of Injury
• normal bioelectric system, nonexcitable tissues
  have a charge
• skin -----
• deeper tissues
• neuraxis
• periphery -------
• Wounds - system is disturbed creates a current
  of injury that initiates tissue healing . . .
  inflammatory process, migration of cells, etc..
• Use of E-stim magnifies the current of injury
  to initiate, maintain, or speed the process.

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Current of Injury cont...

• Further research established
• Wound tissue is () skin around is (-) this
  difference is the skin battery or current of
  injury and must exist for proper healing if it
  fails or is disrupted, then slow/no healing can
  occur. E -stim can help restore the skin
  battery.
• Further supported by evidence that many chronic
  wounds lost () polarity e-stim w/ the anode
  () over the wound enhanced healing. (using DC)
• If healing plateaued, switching polarity good
  outcome
• Kloth Feedar, Phys Ther, April 88

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Phys Ther 1988 methodfor e-stim of wounds

• Monophasic twin-pulse current (HVPC)
• 105 pps
• Amplitude submotor
• Time - 45 min, 5 days a week
• Wound packed with soaked gauze and anode ()
  placed over wound
• Cathode placed 15 cm away, proximal
• Rationale Done to amplify the current of
  injury

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Contemporary Theory Galvanotaxis

• A naturally occurring process whereby
  signaling/messenger systems work via
  bioelectrical mechanisms. (Does not contradict
  the chemical model of human physiology
  chemotaxis).

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Contemporary Theory Galvanotaxis

• Process can be corrected and/or enhanced by
  attraction of cells to the wound thru use of
  anode () or cathode (-)
• Leukocytes, fibroblasts, endothelial epithelial
  cells, etc.. all have polarity and can be
  electrically attracted.
• Treatment polarity depends on stage of the wound
• READ THE ARTICLE Kloth McCulloch (1996)

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Kloth Advances in Wound Care 1996 method

• Monophasic twin-pulse current (HVPC)
• 100 pps, no mention of pulse width
• Amplitude - just below motor
• Time - 60 min, 5 days a week
• Wound packed with soaked gauze
• Polarity - based on wound state
• Other electrode placed 15 - 20 cm away (proximal)
  to complete the circuit
• Done to amplify the injury potential or
  current of injury and produce galvanotaxic
  attraction

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Electrode Placement

• Options
• Directly over the wound
• Directly in the wound
• Straddle the wound
• More information FYI
• http//medicaledu.com/estim.htm

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Some Hx of ESTR

• Why not use LIDC ?? Studies have shown it to
  be effective
• Much longer Rx time and greater frequency of Rx
• electrochemical changes more pronounced
  potentially harmful (due to pH changes in tissue)
• HVPC has a shorter Rx time and less frequent, no
  harmful electrochemical changes in the tissue
• Mechanisms by which biphasic or AC may enhance
  healing are not well-understood.

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ESTR Treatment Tid-bits

• ESTR usually not used on well-healing wounds,
  more for chronic wounds
• DOES NOT replace typical wound care
• Suggest physician cooperation/agreement
• Patient tolerance or refusal a potential issue
  based on the way you describe it.
• Suggest continuing education to become more
  competent.

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Contraindications

• Osteomyelitis
• Malignancies / neoplasms
• Carotid sinus / laryngeal ms.
• Thru the thorax
• Demand-type pacemakers
• Over topical agents containing metal ions
  (iodine, mercurochrome)
• Others as previously learned except for open
  tissue

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Case 37 y.o. black male suffered a crush injury
at work when a heavy object fell on his foot. The
distal phalanx of the hallux was fractured and
the 2nd and 3rd toes were amputated. Three months
of whirlpool treatment at another facility
produced no healing. Treatment of this patient
with aggressive debridement, electrical
stimulation, appropriate product selection and
nutritional support resulted in a favorable
outcome in 5-6 weeks.
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Reimbursement IssuesCenters for Medicare
Medicaid Services (CMS)

• Electrical stimulation for the treatment of
  wounds will only be covered for chronic Stage III
  or Stage IV pressure ulcers, arterial ulcers,
  diabetic ulcers and venous stasis ulcers.
• All other uses of electrical stimulation for the
  treatment of wounds are non-covered.
• Chronic ulcers are defined as ulcers that have
  not healed within 30 days of occurrence.
• Electrical stimulation will not be covered as an
  initial treatment modality.

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Reimbursement Issues . . .

• Electrical stimulation will be covered only after
  appropriate standard wound therapy has been tried
  for at least 30-days and there are no measurable
  signs of healing. This 30-day period can begin
  while the wound is acute.
• Measurable signs of improved healing include a
  decrease in wound size, either surface area or
  volume, decrease in amount of exudates and
  decrease in amount of necrotic tissue. Standard
  wound care includes optimization of nutritional
  status debridement by any means to remove
  devitalized tissue maintenance of a clean, moist
  bed of granulation tissue with appropriate moist
  dressings and necessary treatment to resolve any
  infection that may be present.

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Reimbursement Issues . . .

• Continued treatment with electrical stimulation
  is not covered if measurable signs of healing
  have not been demonstrated within any 30-day
  period of treatment.
• Electrical stimulation must be discontinued when
  the wound demonstrates 100 per-cent epithelialzed
  wound bed.
• This service can only be covered when performed
  by a physician, physical therapist, or incident
  to a physician service.

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HVPC for Acute Edema control

• Based on the results from animal studies, HVPC
  may have an effect upon acute edema FORMATION but
  the effect is short-lived (several hours)
  therefore, treatment is recommended for 30
  minutes every 4 hours for the period of time that
  bleeding/swelling is expected to occur. This
  treatment duration and frequency fits well with
  the RICE protocol but may often be too frequent
  for an individual needing/trying to function
  (work or school). A portable HVPC unit is
  essential (and available)

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• This treatment is indicated for acute trauma
  (sprain, strain, contusion) or post-surgery. The
  situation must be an ACUTE TRAUMATIC CONDITION
  where bleeding, swelling inflammation are
  actively developing. The underlying physiological
  effect is largely unknown but studies often point
  toward an effect upon capillary permeability -
  related to histamine release.

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ELECTROTHERAPY TREATMENT OF SWELLING I EDEMA
STAGE Rx CURRENT Polarity FREQ RESPONSE TIME
ACUTE Control of Formation HVPC (--) 120 PPS SUBMOTOR 30 Min/4 HRS during acute stage
SUBACUTE I CHRONIC Reduction HVPCBIPHASICRUSSIAN N/A Varies need ms. pump MOTOR 20 min daily