THERAPEUTIC DIRECT CURRENT

 INTRIDUCTION: 

• Direct current refers to current passing continuously in the same direction.
• For the purpose of definition therapeutic direct current has been considered to pass for more than 1 second and is sometimes called current are galvanism.
• the medium frequency DC type current consisting of pulses of 125 ms duration separated by intervals of 5 ms duration.
• Hence giving a duty cycle half 96 % is effectively DC. Very low intensity DC is often described as “microamperage DC” or “micro amperage stimulation”.

 

TRANSMISSION:

• Current is passed to the body tissues by means of wet pads, sponge and a bath of suitable solutions.
• The conduction current generated in the operators is changed to a convection currents in the wet pads and tissues.
• after electrode or a conductor with the electrolytes of the pad chemical changes will occur that is the changes of electrolysis.
• The nature of these changes depends on the constituents of the electrolytes and the metal of the electrodes.
• Such a chemical burn formed more likely to occur close to the negative terminal as a result of the alkalis for there.

 

PHYSIOLOGICAL EFFECTS:

SENSORY STIMULATON:

• The patient is aware of the mild tingling or pricking sensation which may be merged into the mild irritation for itching.
• If sufficient current has passed for a long enough an erythematosis of the  skin in will be evidence under both electrons and it is more marked under the negative.

 

HYPEREMIA:

• it is confined it indicates a capillary hypothermia and like that due to heat in which under a dilatation occurs.
• The initial erythema last for about 20 minutes are so but may be made to Erythema over a period of several hours even a day later by another stimulus such as heat or cold.
• The evidence case in the past lead to a idea that vasomotor stimulation and increased circulation promote improved nutrition of the area and speed up the resolution of inflammatory products.

 

ELECTROTONUS:

• Subthreshold stimuli do not cause and action potential but they do affect the membrane potential.
• The cathode produces a local depolarizing potential that Rises rapidly but Falls exponentially with time.
• The anode causes the riverse hyperpolarization.
• These are electrical potentials that occur because altering the  charge across the membrane alters the threshold.
• The outer nerve membrane surface list positive lower than threshold which increases the nerves excitability while making its more positive as the reverse effect.

 

RELIEF OF PAIN:

• The relief of pain has long been claimed as a result of direct current treatments.
• sensory stimulation of cutaneous nerve endings inhibiting pain by means of the pain Gate theory, reasonably account for this phenomenon.
• it is suggested that the Marked hyperemia occurring under the cathode will strong DC help to improve and remove inducing factors.

 

ACCELERATION OF HEALING:

• Various forms of electrical stimulation have been shown to the enhance healing.
• Low density electrical currents lead to augmented and accelerated healing.
• Increase the rate of new bone formation have been shown to occur when small direct currents have been applied to fractures by implanted electrodes.
• This has been used successfully in the treatment of non Union fracture.
• The healing rates after soft tissue particularly superficial open wounds have also be benefited from electrical stimulation.

 

APPLICATION OF DIRECT CURRENT:

• The size of any wound or ulcer to be treated should first be tried to enable the current density to be calculate and to monitor the rate of healing.
• The ulcer packed with  gauze choked in sterile saline to allow adequate conduction of the current.
• The negative electrode is usually employed for the first few treatments partially for its bactericidal effect and for recents considered.
• a malleable electrode wrapped  in saline choked gauze in applied over the wound and secured with strap or bandage.

FOR TISSUE DESTRUCTION:

• At Higher current densities DC will cause tissue damage.
• coagulation of protein occurs under the positive pole and liquefaction under the negative pole.
• This effects will occur if the current density is such as would happen if a bare wire on electrode where placed on or in the skin.
• This effect has been used in the deliberate destruction of unwanted tissue.
• With the large positive dispersive electrode applied in a convenient place the fine needle electrode used in active electrode is introduced into the hair follicle and the current supplied to the liquify and destroy the Hair bearing epithelium.

 

CONTRAINDICATIONS:

• This currents should not be applied to the tissues that contain neoplastic cells. since it is possible but not supported by any evidence that occurrence may enhance the activity of such abnormal cells leading to increased cancerous growth on metastases.
• If the wound has been treated with topical application containing metal or other ions, we should be thoroughly washed outs of the wound before treatments. This is because positively charged ions would be driven into the wound tissue by the anode and negatively charged ions by the cathode. this may cause irritation of the wound.

 THOSE ABOVE ARE COLLECTED FROM SOME BOOKS AND WEBSITES..

THANK YOU,

SRIKUMARAN PHYSIOTHERAPY CLINIC & FITNESS CENTER