The Constant Direct Current Electrotherapy Physiotherapy

1

THE CONSTANT DIRECT CURRENT

The constant direct current, which is sometimes known as constant galvanic current, is unidirectional current of unvarying intensity.

PHYSIOLOGICAL EFFECTS The tissues of body are conductors of electricity because the tissue fluids contain ions and so are electrolytes. Consequently the current, which passes through the body, is convection current, consisting of two-way migration of ions. The conductivity of the different tissues varies according to the amount of fluid that they contain, muscles with a good blood supply, being a good conductor, while fat is poor conductor. The epidermis has a high resistance, about 1000 ohms, as it contains little fluid and the superficial layers do not readily absorb moisture. The resistance of the underlying tissues is much less than that of the skin, so the current spreads considerably once it has passed through the skin and the current density, and therefore the effects, are much greater in the superficial than in the deep tissues. The physiological effects of the constant D.C. are due to two-way migration of ions and may be divided in to two groups, those obtained through the interpolar pathway and those produced at the poles. EFFECTS IN THE INTERPOLAR PATHWAY Dr. Muhammad Ismail Physiotherapist ([email protected])

2

These effects are produced throughout the pathway of the current, but are most marked in the superficial tissues where the density of the current is greatest. The movement of ions causes alteration in the concentration of substances in the tissue fluids and this is thought to accelerate the interchange of materials between the cells and the tissue fluids and to increase cell metabolism. The erythema of the skin, which is observed when the pads are removed after treatment, indicates that the current causes vasodilatation. This undoubtedly takes place in the superficial tissues and has been assumed to occur by the underlying ones as well, although there is no definite proof of this is so. There are several theories as to the cause of vasodilatation. It may be due to moving ions stimulating the sensory nerve endings and so causing a reflex vasodilatation of blood vessels. Irritation of these cells may cause the liberation of the “H” substance. This produces the triple response of dilatation of the capillaries, by a direct effect, dilatation of arterioles, by the axon reflex, and local edema, due to increase permeability of the capillary walls. The vasodilatation may the result of the mechanical action of the moving ions bombarding the walls of the blood vessels.

Dr. Muhammad Ismail Physiotherapist ([email protected])

3

As a result of the vasodilatation there is an increased blood supply to the tissues, an increased supply of the nutritive materials is made available and the removal of the waste products is accelerated. The increased blood supply also produces the sensation of warmth experienced during the treatment. There is no direct production of heat in the tissues as the intensity of the current that can be tolerated is not sufficient for this purpose. POLAR EFFECTS These are the effects, which are produced in the tissues immediately under the electrodes and differ at the cathode and anode. ELECTROTONUS Electrotonus is the effect on the conductivity and excitability of nerves, and can be demonstrated in the laboratory with the gastrocnemius muscle and sciatic nerve of a frog. Electrical stimulation of the nerve produces a muscle contraction, but if at the same time a constant D.C. is applied the strength of contraction is modified. If the anode is applied the strength of contraction is reduced. If the anode is applied (Fig. 119) the strength of the contraction is reduced, as the anode has effect of decreasing the conductivity of the nerves. The cathode has opposite effect of increasing the conductivity of the nerves, and so the strength of the muscle contraction.

Dr. Muhammad Ismail Physiotherapist ([email protected])

4

Anelectrotonus is the decreased excitability and conductivity of the nerve in the region of the anode, Catelectrotonus the increased excitability and conductivity of the nerve in the region of the cathode. Both are due to the development of a P.D. across the plasma membrane of the axon of the nerve as the current passes. The P.D. developed under the anode argument the normal resting P.D. and so makes it more difficult for any pulse to pass, while that under the cathode reduces the resting P.D. and increases the conductivity. Fig. 119 Effect of D.C. on conductivity of nerve.

While these effects can be demonstrated in the laboratory it seems doubtful whether they can occur in the living body, as increase in P.D. on one side of the axon is accompanied by a reduction of that on the other side. At the same time clinical evidence indicates that the effect is produced to some extent. There is no explanation of the relief of pain that follows treatment with galvanism, and further is provided by the greater erythema produced at the

Dr. Muhammad Ismail Physiotherapist ([email protected])

5

cathode than the anode. This probably occurs because the excitability of nerves is increased at the cathode and reduced at the cathode, so that there is a greater reflex vasodilatation at the former than at the later. ELECTROPHORESIS: When a current is passed through a non-living semi-solid electrolyte, such as gelatin, there is an increase in fluid at the cathode and a decrease at the anode. Various explanations of this effect have been given what it is thought to be due to the movement of positively charged colloidal particles which are present in the electrolytes and to which water molecules adhere. When P.D. is applied the colloidal particles, which are considerably larger than ions, migrate slowly away from the anode and towards the cathode, carrying water molecules with them and bringing about the redistribution of fluid. In the living tissues the continual circulation of fluid must to a large extent counteract this effect, but there appears to some reduction in the fluid present in the superficial tissues underlying the anode, and an increase at the cathode. INTRODUCTION OF IONS IN TO THE TISSUES When the constant D.C. is passed through the body there are two-way migrations of the ions in the tissues and also in the solution contained in the pads. Consequently there is an interchange of the ions between the tissues

Dr. Muhammad Ismail Physiotherapist ([email protected])

6

and the pads. Positive ions are repelled by the anode and pass from the pad to the tissues under this electrode, while at the cathode they are attracted from the tissues to the pads.

Fig. 120 Interchange of ions between tissues and pads.

Similarly negative ions move from the pad to the tissues under the cathode and from the tissues to the pad under the anode. Thus ions contained in the pads are repelled into the tissues under the electrode bearing the same charge as the ions, and the current can be used to introduce ions into the tissues, the treatment being known as Medical Ionization. CHEMICAL EFFECTS When a direct current is passed through an electrolyte, chemical changes take place at the electrodes. If the current is applied to the body with anodal electrode in direct contact with the tissues, the tissues are involved in the chemical actions and are destroyed. There is coagulation of the tissues at the anode, while at the cathode they tend to liquefy. When pads are used the chemicals are formed between the pads and electrode but should the pad be Dr. Muhammad Ismail Physiotherapist ([email protected])

7

of insufficient thickness the Acid formed at the anode and the Alkali formed at the cathode soak through to the skin and cause destruction of the tissues. The chemical effects are used in the tissues known as Surgical Ionization, but are also responsible for the burns, which are liable to occur with direct current treatments. THERAPEUTIC EFFECTS, USES AND METHODS OF APPLICATION The constant D.C. is most often applied with pads on opposite aspects of the parts to be treated, so that the current is directed through the deep tissues. THERAPEUTIC EFFECTS AND USES: The increased blood supply makes more oxygen and foodstuffs available to the tissues and removal of waste products is accelerated. These effects help to bring about the resolution of chronic inflammation and are utilized in such conditions as Osteoarthritis, Chronic Rheumatoid Arthritis, Stiff Joint following injuries, Tennis Elbow and Tenosynovitis. The anode and cathode lie fairly close together, so the effects, which are different under the two poles, tend to counteract each other. The increase in blood supply is however, more marked under the cathode than under the anode, and there is a counterirritant effect at the cathode. The moving ions irritate the superficial sensory nerve endings, which have been rendered

Dr. Muhammad Ismail Physiotherapist ([email protected])

8

more excitable by Electrotonus and the marked stimulation of these nerves appear to reduce the impulses reaching the brain from the underlying structure. Pain due to the lesion of the deeper structures is relieved and the method is found to be particularly effective in the treatment of chronic lesions, so when the constant D.C. is applied for the condition mentioned above the cathode is usually placed over the more painful aspect of the part. The effect of the constant D.C. are purely on the superficial tissues so the treatment is of most value for lesions of superficial structures such as the both knee and ankle joints, being much less effective for deep structures such as the hip joints. The constant D.C. alone is rarely an adequate treatment, but is used in conjunction with other forms of Physiotherapy, most usually being a preliminary to active exercises. METHOD OF APPLICATION The pads are placed on the opposite aspects of the structure to be treated, the most suitable surface being chosen. For instance, when treating the knee joint, the pads are usually placed on the medial and lateral aspects, avoiding the irregular anterior and posterior surfaces. The effects of constant D.C. are most marked in the tissues immediately under the pads, so to obtain maximum effect the pads should be as large as

Dr. Muhammad Ismail Physiotherapist ([email protected])

9

possible. Care however be taken that the pads do not approach too close to each other, or the current may concentrate between them. When the structure being treated is equidistant from the surface to which the pads are applied, both pads should be of the same size. When the structure is nearer to one surface than to the other the active electrode, which is as large as is practicable, is placed on the near surface, with a large directing electrode opposite. The intensity of current passing through both pads is the same, so the current density and therefore the sensory stimulation, is less under the large pad than under the small one. Thus undue sensory stimulation under the directing electrode, which might limit the total current tolerated, is avoided. A current density of 2 milliamperes per square inch of pads is desirable and the treatment usually lasts for 20 to 30 minutes. Both the intensity and the duration of the treatment must, however, be determined by the tolerance of the patient’s skin, which varies considerably in different individuals. Treatment is usually applied on the alternate days, as the skin tends to become sore with more frequent applications.

CAHTODAL GALVANISM When the cathodal effects are particularly required, the cathode is applied over the affected structure and a circuit completed with a much larger anode elsewhere on

Dr. Muhammad Ismail Physiotherapist ([email protected])

10

the body. The active pad may be large, covering as much area of the affected structure as possible or when the lesion is localized, a small pad is used.

THERAPEUTIC EFFECTS AND USES The cathodal effects are primarily a marked increase in blood supply to the superficial tissues and relief of pain by counter irritation. Cathodal galvanism may be used for chronic inflammatory and posttraumatic conditions, being particularly effective when the lesion is localized and a small active pad is used. Theoretically a large pad should be of value because of the widespread effects but it often proves a less effective method than the direct current through the lesion, possibly because the patient tend to tolerate the high current density with the latter method. The increase in blood supply may also be of value when the circulation is defective, as in chilblains, lower motor neuron lesions, etc. It has been claimed that the catophoretic effect is of value in softening the scar tissue, and cahtodal galvanism my be used in conjunction with active exercise when scare tissue is limiting movement and muscle action.

METHOD OF APPLLICATION The cathodal plate is placed over the site of lesion or in suitable cases; a cathodal bath may be used. The indifferent pad should be appreciably larger than the active, so that the current density under this is low, otherwise the

Dr. Muhammad Ismail Physiotherapist ([email protected])

11

sensory stimulation in this area may limit the total current that can be applied. A high current density is desirable and when the active pad is small 2 milliamperes per square inch or more may be tolerated, although if a large active pad is used it is not as a rule possible to apply so high a current density. The duration of treatment is usually 20 to 30 minutes, both this and intensity of the current is must be determined by the patient’s tolerance. The treatment is usually applied on the alternate days.

ANODAL GALVANISM When the anodal effects are particularly required, the anode is applied over the area to be treated and the circuit completed with a larger cathode on the body. THERAPEUTIC EFFECTS AND USED As a result of the reduced excitability and conductivity of the nerve there is relief of pain and muscle spasm. This effect is utilized in the treatment of recent injuries, such as sprained ankle, and in more acute stages of inflammation, as Rheumatoid Arthritis and Tenosynovitis. For these conditions the anode is more effective for relieving pain than the counter irritation produced by the cathode. Anodal galvanism may also be used in palliative treatment of, for example, sciatic pain in prolapsed vertebral disc.

Dr. Muhammad Ismail Physiotherapist ([email protected])

12

The anaphoretic effect may be utilized to assist in the reduction of recently accumulated fluids due to injury or inflammation in, for example, synovitis and Bells palsy. The method is not, however, of valued for more than 7 to 10 days following the exudation, as after this time the organization of the fluid has commenced. The slight increase in the blood supply, which occurs at the anode, is of value in the above condition, to improve the supply of nutritive materials to the tissues and to accelerate the removal of the waste products. The increase in blood supply is not, however, sufficient to cause increased pain from site of lesion in the area. In all the conditions mentioned above anodal galvanism is an accessory to the other physical measures, which are commonly employed. METHODS OF APPLICATION A large anodal pad is applied to cover the as much of the swollen or painful area as possible, or an anodal bath, may be used. The indifferent pad is applied to the suitable area, at some distance from the anode in order that it shall not interfere with the anodal effect. It should be larger than the anode so that the patient is not unduly conscious of it, though as a low current density is used, it is not likely to limit the intensity of current that can be appl8ied. The treatment is found to be most effective if a low current

Dr. Muhammad Ismail Physiotherapist ([email protected])

13

density, ¼ to ½ a milliampere of per square inch of pad, is applied for 45 to 60 minutes. As the current density is low and the treatment effective only for a limited period, the skin usually tolerates daily applications.

TECHNIQUE OF TREATMENT PREPARATION OF APPARATUS The source of current is either a cell battery or apparatus which uses the main supply, the former being advisable for any part of the head. The apparatus must be tested before applying the current to the patient. Leads are attached to the terminals and held with the free ends not touching each other, in a bowl of tape water. The current is turned up and the needles of the milliamperemeter watched to ensure that the regulation of the current is even. The control should be turned up as for as will be required for the treatment, or faults, for instance in the potential divider may pass undetected. Tap water is used because it has a fairly high resistance and so the control can be turned well up without passing excess current through the milliamperemeter. The polarity can be checked by observing the bubbles from the cathode. The polarity is rarely incorrectly marked but is easily checked in the course of the other test. The operator may then test the current on herself as for the faradism, and if she is not familiar with the

Dr. Muhammad Ismail Physiotherapist ([email protected])

14

apparatus, it is advisable to test the shunts to ensure that the circuit is not broken when the switch is moved from one position to another. Pads similar those used for faradism are required, but they must be at least half an inch in thickness for a treatment of the average intensity and duration in order that the chemicals formed at the electrodes shall not soak through to the skin. Sixteen thicknesses of lint or eight of turkish toweling, evenly folded with no creases or raw edges, are suitable. The pads are soaked in warm 1 percent saline, care being taken that the salt is fully dissolved as otherwise it may cause concentration of current. The electrodes are half an inch smaller all round than the pads, with rounded corners.

PREPARATION OF THE PATIENT The skin is washed and abrasions protected as for faradism, but in addition skin sensations must be tested at the first attendance to ensure that the patient will be able to detect any concentration of current. The test may be made with a blunt object and cotton wool.

APPLICATION OF PADS AND ELECTRODES The skin moistened with saline and the pads and electrodes are applied. Care must be taken that no metal comes in contact with the skin. The electrodes are covered by the half an inch larger all around than the pads and are firmly held in position with the bandages. The whole of the both the pads must be Dr. Muhammad Ismail Physiotherapist ([email protected])

15

covered by bandage and it is advisable to bandage the leads away from the skin. If the surface is irregular, hollows may be padded with the wool soaked in saline, or brown wool may be placed over the hollows, on top of the pad and electrode, in order to exert extra pressure in these areas and maintain even contact between the pad and the skin.

APPLICATION OF CURRENT The patient is warned that she will experience a pricking sensation as the current is increased, which will gradually pass off and be replaced by a feeling of warmth, also that she must report any discomfort or concentration of current. The currant is turned up slowly, taking about 5 minutes to reach the maximum, inorder to allow time to skin resistance to fall. It will be noticed that during this period the pointer of the milliamperemeter continues to move up when the control is stationary, due to fall in resistance as the ions enter the skin. When the current is first applied the ions mainly enter through the hair follicles and ducts of the sweat glands where the resistance is less than that of the intervening epidermis. The pricking sensations experienced at this stage are thought to be due to stimulation of sensory nerve endings at the basis of hair follicles. Due to the continuous passage of current, ions enter the epidermis and reduce its resistance, so that the distribution of

Dr. Muhammad Ismail Physiotherapist ([email protected])

16

current becomes more even. The pricking passes off and the sensation of warmth is due to increased blood supply. Throughout the treatment the operator should be with the call of the patient and should inspect the meter at frequent intervals. If the needle goes up after it has stabilized, the situation must be investigated. It may be due to the bandage becoming damper and forming a short circuit between the pads, or the skin may be breaking down with the development of a burn. It the patient reports discomfort, especially at one spot, the current must be turned down and the area examined. At the conclusion of the treatment the current is reduced slowly and turned off. The skin is washed to remove any chemicals that may have soaked through the pads, dried and powdered or a soothing cream such as a glycol jelly may be applied. The skin should be evenly red under the cathode, while the erythema at the anode is usually less marked and may be even. The intensity of the current and duration and frequency of treatment have been considered with the therapeutic effects. At the first attendance it is usual to apply rather less current, and for a shorter time, than on the subsequent occasions, in order to ensure that there is no adverse reaction of the skin. A record should be kept of the size and position of the pads, the

Dr. Muhammad Ismail Physiotherapist ([email protected])

17

intensity of the current, the duration of the treatment and the skin reaction at each attendance.

TREATMENT IN BATHS The advantages and disadvantages of applying the current in baths and the methods of arranging the treatment have been considered in the chapters of faradic and sinusoidal currents. The same principles apply with the galvanic baths but a few additional precautions are necessary. PRECAUTIONS When the treatment is applied in bath the danger of burn is rather less than when the treatment is applied with pads and electrodes are used, as any chemical which may be formed dissolve in the water and so are diluted. Burns could occur however if metal were in contact with the tissues, so rings, etc, must be removed and the patient warned not to touch any electrode. Breaks in the skin are protected by petroleum jelly, as they would cause discomfort due to concentration of ions. The danger of shock is greater than with the pads and electrodes. The reason for this and the necessary precautions are given in chapter 11. In addition the patient should be warned not to take the limb out of the bath during treatment, as this would break the circuit and cause a shock.

Dr. Muhammad Ismail Physiotherapist ([email protected])

18

The control is turned up and down very slowly as, owing to the low skin resistance. Slight variation in the EMF causes an appreciable variation in the intensity of current. The patient’s sensation is the main guide to the intensity of current that should be applied. USES OF THE BATH TREATMETN Treatment in the baths is satisfactory where a widespread effect is but the method is not suitable for the localized application. It is of most value for increasing the blood supply to a limb and for the application of the current to an irregular area such as the hand or the foot, but as the limb must be dependent it is not suitable for the treatment of the swollen areas. In some cases a monopolar bath may conveniently be used as an indifferent electrode.

DANGER AND PRECAUTIONS ELECTRIC SHOCK Electric shock is one of the dangers associated with the application of the constant D.C. The ways in which shocks may occur are considered in chapter 11, also the treatment of the shock and the precautions that should be taken.

ELECTROLYTIC BURNS

Dr. Muhammad Ismail Physiotherapist ([email protected])

19

Burns produced by the constant D.C. are electrolyte or chemical burns. Tissue is destroyed and the burn appears, as a grey spot surrounded by the reddened area. As tissue is destroyed, healing is by second intention and is liable to slow. The area should be kept dry and care must be taken that it does not become infected. The burn is usually protected by dry sterile gauze and healing can be hastened by the application of infrared and ultraviolet rays. If a burn should occur it must be reported to the medical officer. Burns are most liable to occur if the current is applied with metal in contact with the tissues, as the tissues are then directly involved in the chemical actions. This may occur if the electrode, clip, or end of the lead projects over the edge of the pad, if there are small pieces of metal on the pad, which might have been dropped when trimming a lead or electrode, if there are metal objects, such as ring in contact with the tissues, or if there is metal embedded in the tissues, e.g. a plated fracture. Concentration of current may also cause burn as more chemicals are formed in the area of concentration than elsewhere. This may be due to a break in the skin to the presence of undissolved slats on the pad, to pads of uneven thickness or with creases or with raw edges of pads that are unevenly damp. It may be due to an electrode being bent, cracked or much smaller than the

Dr. Muhammad Ismail Physiotherapist ([email protected])

20

pad, to he pads being too close together so that current concentrates between them. If the pads are too thin for the intensity and duration of the treatment, chemicals may soak through skin, or if the pads have been properly washed after a previous treatment and still contain some chemicals, the same thing may occur. If the patient has not received adequate warning of the sensations she will experience, she may tolerate too much current or concentration may pass undetected. Application of liniment may render the skin more susceptible to damage, and so it is wiser not to apply the current to areas on which liniment has recently been used.

GALVANIC RASH A rash may be produced on the skin as a result of the passage of the constant D.C., individuals with sensitive skins being particularly liable to show this reaction. The type of rash varies in different cases; it may be red, like nettle rash, or small white spots or minute blisters may appear. The skin should be washed and soothing cream applied. This is better than powder, as the skin tends to become dry and chapped with repeated application of the current. The presence of the rash should be reported to the medical officer as, though it will often disappear before the next treatment, the patient’s skin is unlikely to tolerate a long course of treatment.

Dr. Muhammad Ismail Physiotherapist ([email protected])

21

GIDDINESS This is liable to occur if the current is passed through the region of the semicircular canals, particularly when the intensity is being varied e.g. in treatment of the ear or mandibualr joint. When applying current to these areas the patient must be fully supported, the current increased and decreased very slowly, and the operator at hand throughout the treatment.

CONTRAINDICATIONS For reasons already explained, the current must not be applied to anesthetic areas of the skin or where there is metal embedded in the tissues. Also there are many breaks in the skin, it is impossible to give a satisfactory treatment.

Dr. Muhammad Ismail Physiotherapist ([email protected])

22

Chapter 17

IONIZATION THEORY OF MEDICAL IONIZATION Medical ionization is the introduction of therapeutic ions in to the tissues by the action of the constant direct current. One pad is soaked in a solution containing the ions to be introduced, and placed under the electrode bearing the same charge as the ions. The circuit is completed by a second pad and electrode, and when the current is passes there is an interchange of ions between the pads and the tissues. The required ions are repelled in to the tissues by the like charge on the active electrode. PROOF THAT IONS ENTER THE TISSUES An experiment to prove the entry of the ions into the tissues under the influence of the current was performed by Leduc.

Fig. 121 Leduc’s Experiment

Dr. Muhammad Ismail Physiotherapist ([email protected])

23

Two rabbits were connected in series with each other to a source of D.C. One pad on each rabbit was soaked in a solution of a salt of strychnine, the other in a harmless solution. On one rabbit the cathode was placed over the pad containing the strychnine ions, on the other the anode (Fig. 121). The strychnine bear a positive charge and, when current was passed, the rabbit with the pad containing the strychnine ions under the anode A died, while the other rabbit B, was unaffected. Thus the entry of the ions was due to repelling effect of the anode, not to absorption through the skin. There is other evidence that the current causes the ions to enter to the tissues. A visible reaction of the superficial tissues can be observed following certain ionizations, such as histamine, and zinc when applied to wounds, but this reaction is not produced unless the electrode bears the same charge as the ions. Also following ionization with some substances as lithium, the ions may be detected in the urine, although they are not normally present and could not have come from any other source. VALUE OF THE METHOD It is not possible to achieve any great depth of penetration of the ions. Their speed of movement is slow, and the current intensity and duration of treatment are limited by the patient tolerance. There are many ions already present in the tissues, and frequently these move more readily than those

Dr. Muhammad Ismail Physiotherapist ([email protected])

24

introduced. Also as soon as the ions reach the blood vessels they are carried away from the area in the blood stream. As the ions do not penetrate beyond the superficial tissues, no direct effect of the ions can be obtained on the deep structures. Where, however, the effects are required on the skin, mucus membrane or surface of wounds, the method is of value. It has the advantage that the treatment cab be accurately localized and that dosage can be exactly controlled. Some ions such as the iodine, mentioned below, may be introduced to enhance the effect of the constant direct current, and when medical ionization is used the effect of the constant D.C., are obtained in addition to those of the ions which are introduced. A considerable variety of the ions have been used for medical ionization in the past, and new ones are introduced from time to time, but only in a few cases do their effects warrant extensive use. A few examples are given below to illustrate the principles of treatment, and it should be possible to apply those principles to other ionization which may be required. EFFECTS OF VARIOUS IONS The following ions bear a negative charge and so are introduced under the cathode. IODINE IONS

Dr. Muhammad Ismail Physiotherapist ([email protected])

25

These are obtained from the solution of potassium iodide and have an irritating effect on the superficial sensory nerve endings. Consequently the iodine ions increase the vasodilatation and relief of pain by counter irritation which is normally obtained at the cathode. They are used in the treatment of chronic inflammatory lesions. Iodine ionization is also sometimes used for softening superficial scars, but the effect is probably due to the increases blood supply and fluid contents of the tissues, rather than to any specific effect of the iodine ions. CHLORINE IONS These are obtained from solution of sodium chloride and have been said to cause softening of scar tissues, but the effects are probably due entirely to the action of the cathode. SALICYLATE IONS These are obtained from a solution of the sodium salicylate and are sometimes used in the treatment of rheumatic conditions. It is unlikely that the salicylate ions reach the site of the lesions, and the main effect is probably relief of pain from the analgesic effect of the salicylate ions on the superficial sensory nerve endings. ALBUCID (Sulphacetamide ions)

Dr. Muhammad Ismail Physiotherapist ([email protected])

26

These are obtained from the solution of Sulphacetamide. They destroy certain bacteria and are sometimes used in the treatment of infection of the eye. The following ions bear a positive charge and so are introduced under the anode. ZINC IONS These are obtained from a solution of zinc sulaphate or zinc chloride and are often used in the treatment of infected superficial wounds, sinuses ands mucus membranes, also for destroying exuberant granulations on wounds, for some infections of the ear, hay fever and certain eye conditions. When the zinc ions pass in to the superficial tissues, they react with the tissue proteins forming zinc albuminate, which appears as pearly grey film over the surface and is adherent to the underlying tissues. Thus effects are most apparent when ionization is applied to the surface of the wounds, in which case the superficial cells are destroyed by their reaction with the zinc ions. The ions also have a bactericidal effect. Thus if wound is treated with zinc ionization, the infected or indolent superficial layers of tissues are destroyed, the wound is sterilized and the layer of zinc albuminate seals the surface, preventing the entry of the bacteria. The bactericidal effect is utilized in infections of the eye and ear, while in the treatment of hay fever the

Dr. Muhammad Ismail Physiotherapist ([email protected])

27

ionization serves to reduce the sensitivity of the nasal mucus membrane. The technique required for these conditions is described in the section on techniques for special areas. COPPER IONS These are obtained from a solution of copper sulaphate, and have similar effects to zinc ions, except that instead of zinc albuminate a bluish green film of copper albuminate is formed. They are used in the treatment of some skin conditions and fungus infections and may replace zinc ions in the treatment of wounds. The technique is similar to that required for zinc ionization, IONS OF VASODILATOR DRUGS Histamine is a vasodilator which in the past was widely used for ionization, but in recent years has largely been replaced by Renotin. When histamine ions are introduced in to the tissues the triple response is produced. This is, dilatation of the capillaries by the direct action of the histamine, dilatation of the arterioles by the axon reflex and exudation of the fluid and local edema, as a result of the increased permeability of the capillary walls. A white raised wheal is formed, surrounded by reddened area, or flare. The wheal is due to local edema and the flare to dilatation of the arterioles. If an appreciable quantity of the histamine is carried round the body in the blood

Dr. Muhammad Ismail Physiotherapist ([email protected])

28

stream it causes wide spread vasodilatation, fall in peripheral resistance and fall in blood pressure. The first sign of this general effect is usually flushing of the face and neck, and there may be giddiness, a prickling feeling in the eyes and an increase in the pulse rate. Headache is liable to follow. Renotin produces a similar local reaction, but only on very rare occasions a general effect, so is commonly used in preference to histamine. The local effects of anodal galvanism are similar to, but more marked than those produce by cathodal galvanism. The local hyperemia and counter irritations are of value in the treatment of chronic rheumatic and post traumatic conditions such as osteoarthritis, rheumatic arthritis, fibrositis and tennis elbow, particularly if the lesion is localized. The vasodilatation is beneficial in some circulatory effects, such as Raynaud’s disease and the increase in blood supply and the exudation of fluid into the tissues may help to soften superficial scar tissues. Special techniques are required for ionization with the vasodilators and are described below. TECHNIQUES OF MEDICAL IONIZATION Ionizations which require special techniques are considered separately, but for the remainder the technique is similar to that for a constant D.C. treatment. A directing electrode may be placed opposite to that from which

Dr. Muhammad Ismail Physiotherapist ([email protected])

29

the ions are introduced, so that they penetrate as deeply as possible, or an indifferent electrode may be applied to some convenient area. The pad under the active electrode is soaked in a 1 or 2 percent solution of a salt of the substance to be introduced and placed under the electrode bearing the same charge as the ions. The number of the ions introduced into the tissues depends on the intensity of the current and the duration of the treatment i.e. on the quantity of the electricity passes. Therefore as high a current density as the skin can tolerate is usually applied for 30 minutes, the treatment being given on alternate days. SOLUTION FOR IONIZATION The pad is commonly soaked in a 1 or 2 percent solution of the selected salt. Use of the stronger solution does not increase the number of the ions introduced, because this depends on the current intensity, which is limited by the patient’s tolerance. The 1 or 2 percent solution contains an adequate number of ions, so stronger solutions are a waste of the salt and may irritate the skin. One ounce of salt dissolved in 100 ounces of water makes a 1 percent solution and produces 100 fluid ounces of the solution, as the salt does not increases the volume of the liquid. To make one pint of the solution ½ ounces of the salt is dissolved in 1 pint of water or 20 fluid ounces (1 pint =

Dr. Muhammad Ismail Physiotherapist ([email protected])

30

20 fluid ounces). Stronger solutions are often stored in the departments and are diluted as required. To prepare 1 percent of solution from a stronger solution, one part of the solution is added to 19 parts of the water, while a 2 percent solution requires a 2 parts of the solution to 18 parts of the water. TECHNIQUES OF IONIZATION WITH VASODILATOR DRUGS HISTAMINE IONIZATION The treatment must produce general effects so the patient should receive the ionization reclining on a couch and fully supported, and the pulse is taken before commencing treatment. The indifferent electrode attached to the negative terminal of the source of D.C., is applied to some convenient area or a directing electrode may be used. The skin of the area to which the active electrode is applied is cleansed with ether soap and outlined with a skin pencil. It should not exceed 24 square inches. The histamine can be applied on the area by means of a piece of lint soaked in 1 in 5000 solutions of histamine acid phosphate in distilled water or more usually in the form of 1 or 2 percent jelly. The jelly is spread evenly on the marked area. The patient is warned to report any discomfort, and throughout the treatment the operator must watch for any sign of general reaction, which are an indication to stop the ionization. There are various methods for assessing the dose of the histamine ionization, but ¼ to ½ milliampere per square inch of the

Dr. Muhammad Ismail Physiotherapist ([email protected])

31

active pad for three minutes is suitable for the first treatment. Provided there are no ill effects, this is increased at subsequent treatments until a complete wheal is obtained, but the dose should not exceed 120 milliamperes a minutes. At the end of the treatment pads and electrodes are removed and the skin swabbed with methylated ether to remove all traces of the histamine. The patient should rest then for three quarters of an hour to allow the pulse rate and blood pressure to return to normal, and she should be warned to take no strenuous exercise for some hours. Notes are kept of the size of the area treated, the current intensity, duration of treatment, the local reaction and any general effect. The single piece of lint used for the histamine ionization must be destroyed and the pad washed and reserved for these cases. Histamine is a poison and must be replaced in the drug cupboard immediately after use. All equipments that have been in contact with the histamine must either be destroyed or cleaned with spirit, and the physiotherapist must take care that she does not get the histamine on her hands. RENOTIN IONIZATION The technique of application may be similar to that described for histamine ionization except that the precautions necessitated by the possible fall in blood pressure need not to be taken. Alternatively a much large area may be

Dr. Muhammad Ismail Physiotherapist ([email protected])

32

treated, in which case a current of 2 to 6 milliamperes is applied for not more than four minutes, irrespective of the size of the area. When this method is employed the Renotin is spread on the skin and covered with a piece of damp lint as before, but instead of using a pad and electrode, the lint is impregnated with aluminum. The felt mould to the area more readily than does a large electrode and a small electrode is placed in contact with the aluminized surface provides the connection to the source of the current. Although no general reaction is anticipated, it is advisable to warn the patient not to take strenuous exercise for 3 to 4 hours after the treatment. TECHNIQUES FOR SPECIAL AREAS A SEPTIC ULCER OR WOUND Zinc ionization is described, but similar technique is used for the introduction of other ions. An indifferent pad and electrode are applied to some convenient area, which need not to be exactly opposite to the active electrode as deep penetration of the ions is not essential. A high current density employed for the wound so the indifferent pad must be of such a size that the current required for the wound does not cause undue sensory stimulation in this area. When applying the electrode to the wound, all aseptic precautions are observed. The wound is cleansed with one percent zinc sulaphate solution and any scabs are removed. The skin surrounding the

Dr. Muhammad Ismail Physiotherapist ([email protected])

33

wound is dried and a pad of sterile gauze is soaked in the zinc sulaphate solution and fixed over the wound. Any crevices are filled with ribbon gauze soaked in the zinc sulaphate solution before applying this pad. A piece of cellophane, rather larger than the pad, is cleaned with methylated ether and placed on top of the gauze. This prevents the entry of bacteria, and the pad and the electrode on top of it need not to be sterile. A pad of lint is soaked in tap water and applied over the cellophane, then the electrode connected to the positive terminal of the source of the constant D.C. the pad may extend beyond the edges of the wound, but as the resistance of the skin is considerably higher than that of the wound surface, most of the current passes through the latter. The dose measured in milliampere minutes per square inch of the wound, 30 milliampere minutes per square inch being suitable. Thus if the area of the wound is 2 square inches, and the patients tolerates a current of 6 milliamperes, i.e. 3 milliamperes per square inch of the wound, the treatment is given for 10 minutes, while if 12 milliamperes are tolerated, only five minutes are required. At the end of this time the current is reduced, the pad is removed and the wound examined. The gauze under the cellophane should be adherent to the surface of the wound, and must not be disturbed, or the covering of the zinc albuminate will be broken. One corner of the gauze may be raised to inspect the wound and if the

Dr. Muhammad Ismail Physiotherapist ([email protected])

34

surface has turned grey, an adequate treatment has bee applied. If the covering of the zinc albuminate has not formed, the current is applied for a further period. An alternative method of assessing the dosage is to continue the treatment until the intensity of the current falls, indicating that the layer of zinc albuminate, which has a high resistance, has formed. After the treatment a dressing of dry, sterile gauze is applied over the adherent layer of gauze. The treatment is not repeated for at least a week, to allow any sloughs to separate, and only two or three treatments are commonly required. A SINUS A sinus is a track leading from the surface of the body to a deep area of infection, and for permanent healing to occur, it is essential to sterile the base of the sinus. Zinc ionization may be used for the treatment of a sinus and is applied with a zinc rod in direct contact with the tissues. When a current is passed through the ions of the sodium chloride using zinc electrode, zinc ions from the electrode enter the solution at the anode. Similarly, when the current is applied with the zinc anode in contact with the tissues, zinc ions enter the tissues, zinc ions enter the tissues and producing the same effects as when a pad soaked in a zinc sulaphate solution is used. The upper part of the zinc rod may be encased in a fine rubber tube, so that

Dr. Muhammad Ismail Physiotherapist ([email protected])

35

entry of the ions is confined to the deeper parts of the sinus. When applying the treatment large indifferent electrode is placed on some convenient area, then the sinus cleansed with the zinc sulaphate solution. This can be done most effectively with a syringe, and some of the solution is left in the sinus, so that the zinc ions may reach the parts inaccessible to zinc rod. The rod previously sterilized by boiling, is introduced into the sinus and the current applied. The dose may be assessed in milliampere minutes per inch of rod, 30 milliamperes minutes per inch being suitable or the current applied until the intensity falls. When the current turned down it is found that the zinc rod is adherent to the walls of the sinus, but it cab be loosened by reversing the polarity and applying a few milliamperes of the current for ½ to 1 minute. The moistening effect of the cathode frees the rod so that it can easily be removed from sinus. SCARS Ionization can be used in the treatment of contracted and adherent scars, in an attempt to soften the scar tissues so that it can be stretched and freed from the surrounding structures. The aims of the ionization are to increase the blood supply and exudates of fluid in to the tissues and the ions used may be Histamine, Renotin, Iodine or chlorine. When using histamine or Renotin the

Dr. Muhammad Ismail Physiotherapist ([email protected])

36

technique and dosage are the same as those described in the section on ionization with vasodilator drugs. When iodine or chlorine ionization is used the effects are those of the cathodal galvanism rather than those of the ions introduced. Consequently, in order to ensure that the current passes through the scars, the surrounding skin is protected with petroleum jelly and brown wool, or with jaconet. The skin has lower resistance than the scars and if it were not protected, very little current would pass through the scar itself. As the scar is anesthetic, the dosage must be progressed with considerable caution. At the first treatment not more than 1 milliampere of current per square inch of scar is applied for 10 to 20 minutes and the effects are carefully observed, progression being made at subsequent treatments only if there is no severe reaction. THE EAR Inflammation of the middle ear behind the tympanic membrane may result in the formation of an abscess, the condition being known as otitis media. The membrane becomes inflamed and more perforate, pus escaping into the external auditory meatus. Zinc ionization is being employed to clear up the inflammation in the middle ear, when there is chronic discharge of pus through the perforation of the membrane. The ear is cleansed and syringed with warm solution of zinc sulaphate, which can be made up as follows; zinc

Dr. Muhammad Ismail Physiotherapist ([email protected])

37

sulaphate 20 grains, glycerin ½ ounce and water to a pint. At the conclusions sodium must be left in the middle ear and external auditory meatus and it is important that the air bubbles are removed, otherwise the zinc sulaphate solution does not reach the middle ear and the ionization is valueless. An indifferent electrode is applied to some convenient area, then a vulcanite speculum, which contains a zinc wire electrode, is placed in the ear and the solution is added until the speculum is half filled. The active electrode is connected to the anode and a current of 2 or 3 milliamperes passed for 10 minutes. The ionization is repeated at weekly intervals, two or three commonly being required. THE NOSE Hay fever is an acute inflammation of the mucus membrane to the nose, which occurs in persons who are hypersensitive to pollen. Zinc ionization to the mucus membrane of the nose before the hay season commences will often prevent the attack during summer. An indifferent electrode is applied to some convenient area, then the mucus membrane of the nose anesthetized by spraying with cocaine and adrenaline. The nose is packed with layers of the ribbon gauze, soaked in a zinc sulaphate solution similar to that used for the ear and as the packing is an expert work and it should not be under taken without special training. A zinc rod connected to anode, makes contact with

Dr. Muhammad Ismail Physiotherapist ([email protected])

38

the gauze in each nostril and care must be taken that the rod does not come in contact with the nasal mucus membrane. A current of 5 milliamperes is applied for ten minutes and a course of six treatments is usually adequate. THE EYE Corneal ulcer can be treated with zinc ionization, and iodine ionization may prove beneficial for the corneal opacities which sometimes follow corneal ulcers. Zinc or iodine ionization may be used for keratitis, a chronic inflammation of the cornea, and the Sulphacetamide (Albucid) ionization for intensive conjunctivitis. Similar technique is required for all these ionizations. The patient is treated in lying position and the indifferent electrode is applied to some suitable area, e.g. the forearm. The eyelids are inspected and any abrasions protected by petroleum jelly. A ½ percent solution of potassium iodide, zinc sulaphate or Sulphacetamide is used and a drop put in to the medial corner of the eye. The patient blinks; so that the solution runs over the eye then the lid is closed and damped with the solution. A pad of white wool soaked in the solution is placed over the closed lid, extra padding in the hollow in the medial corner of the eye is often being necessary. The electrode is usually applied on top of this and should be as light as possible. A special copper gauze electrode may be used and the lead should be twisted in to the electrode to avoid the weight of a

Dr. Muhammad Ismail Physiotherapist ([email protected])

39

clip. Brown wool is spread over the electrode to bring the padding up to the level of the forehead and the application is secured with the small sterilized bandage. Alternatively if the condition of the eyelid is poor, an eyebath electrode may be used. This is a rubber eye bath with metal electrode with the metal base connected to terminal outside. The bath is filled with the solution and the *site* round the eye moistened. The patient puts the eye in the bath, and then lies down, the electrode being maintained in position by the suction of the rubber on the damp skin. For zinc ionization the active electrode is connected to the anode, fro iodine and Albucid to the cathode. For the treatment of the conjunctivitis the active electrode may be made positive and negative an alternative treatments. When it bears the same **** (The notes are not complete as the old material was a little lost and only few lines are missing.) Compiled By: E-mail: Comments:

Dr. Muhammad Ismail Physiotherapist [email protected] Feel free to pass.

Dr. Muhammad Ismail Physiotherapist ([email protected])