SWD FINAL.pptx

Physiotherapy modalities

1. SHORTWAVE DIATHERMY PRESENTED BY GROUP 1 MPT 2 ND Semester COURSE: MPT19206 Electrodiagnosis and Physical Agents Thursday, 6 January, 2022

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3. INTRODUCTION The term ‘diathermy’ is a Greek word ‘ dia ’ means ‘Through’ ‘ thermy ’ means ‘heat’ Diathermy is applied using electromagnetic waves that produce heat, but are non ionizing. Short wave diathermy used for therapeutic purpose posses : Frequency - 27.12 MHz Wavelength - 11 m. Short wave energy can be delivered via a continuous mode or a pulsed mode. The continuous short wave is delivered by capacitive or inductive methods and pulsed SWD is of same frequency & delivered in the form of pulses. Thursday, 6 January, 2022

4. PRODUCTION The shortwave diathermy consists of 2 circuits: Oscillator circuit Patient or Resonator circuit COMPONENTS OF SWD: Oscillator/ Machine circuit It consists of: Main supply Triode valve Grid leak circuit Oscillator coil Thursday, 6 January, 2022

5. B. Patient / Resonator circuit It consists of: Resonator coil- The high frequency and high magnitude current from the oscillator flows in the resonator coil by EMI. Resonator condenser- It is a variable condenser , used to store electric charge. It is used for tuning both the circuits to obtain maximum heating of tissues. It consists of two metal plates separated by a insulator called dielectric. If the plates are given two opposite static charges, lines of forces concentrate between the plates and electric field is created. Electrodes - Output of SWD machine is connected to two types electrodes; Pad or Disc electrode Ammeter - It shows maximum reading when both circuit resonate. Tissues Thursday, 6 January, 2022

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7. WORKING: The step up and step down transformer is connected to power supply. The current passing through the primary coil of step-down transformer induces EMF in secondary coil, which produces current via cathode filament of the triode valve. THERMIONIC EFFECT – Once the cathode filament receives current from secondary coil, the cathode omits electrons. Similarly, the primary coil of the step up transformer induces EMF in the secondary coil, which is connected to anode and now, anode is capable of conducting current. The cathode filament releases electrons, which passes through grid to the anode. The grid is neutrally charged now . Thursday, 6 January, 2022

8. The electrons flow from cathode to anode and passes via oscillator coil (CD), which induces EMF in coil AB from B to A.. The end of coil AB is connected to grid of triode valve, which accepts the electrons from coil AB and gets negatively charged, thus blocking the flow of electrons from cathode filament. Now the condenser gets depolarized. When the current flows in oscillating coil from D to C EMF is induced from A to B and the Grid loses the negative charge and starts conducting the current. Thursday, 6 January, 2022

9. Resonator circuit is coupled to the patient circuit by inductors and a high frequency current is produced in it by electromagnetic induction. When both the circuits are in resonance, maximum current will flow in resonator circuit and for this product of conductance and inductance must be the same for both the circuits. SWD current is obtained by discharging the condenser. The capacitor discharges when accumulated charges are allowed to flow off the plates to provide the high frequency current. A condenser is made to charge and discharge regularly. Thursday, 6 January, 2022

10. PHYSIOLOGICAL RESPONSES TO SHORT WAVE DIATHERMY THERMAL EFFECTS: Not capable of producing depolarization and contraction of skeletal muscles. Wavelength too short in duration. Thursday, 6 January, 2022

11. The primary effects of diathermy are those of heat in general. Rise in tissue temperature. Increased blood flow. Dilation of the blood vessels. Increased filtration and diffusion through different membranes. Increased tissue metabolic rate. Changes in enzyme reactions. Alterations in the physical properties of fibrous tissues. Decreases joint stiffness. Certain degree of muscle relaxation. Analgesia. Thursday, 6 January, 2022

12. Diathermy heating doses are not precisely controlled thus the amount of heating cannot be -accurately measured. Heating = Current density 2 x Resistance. Thursday, 6 January, 2022

13. NON-THERMAL EFFECTS: Pulsed SWD used to treat soft tissue injuries and wounds. Related to Depolarization of damaged cells Loss of cell division Loss of proliferation Loss of regenerative capabilities. Repolarization corrects cell dysfunction. Sodium pump reactivation ( allows the cell to regain normal ionic balance). Thursday, 6 January, 2022

14. THERAPEUTIC EFFECTS OF SHORT WAVE DIATHERMY Effects on Inflammation Effects in bacterial infections Relief of Pain Effects on muscle tissue Traumatic conditions Reducing healing time Thursday, 6 January, 2022

15. Effects on Inflammation The dilatation of arterioles and capillaries results in an increased flow of blood to the area which increases supply of oxygen and nutritive material. This increased flow of blood enhances the supply of more antibodies and white blood cells. The dilatation of capillaries increases the exudation of fluid into the tissues and this is followed by increased absorption which along with the increased flow of blood through the area assists in the removal of waste products. Thursday, 6 January, 2022

16. Effects in bacterial infections SWD increases the circulation of blood which increases the number of WBC and antibodies in the affected region which help in removing infection. Thursday, 6 January, 2022

17. Relief of Pain The mechanism of pain relief is explained by: Sedative effect due to mild degree of heating Removal of noxious chemical (waste products of metabolism) Counter irritation effect due to superficial heating which block the pain transmission at pain gate. Relief of pain also accompanies resolution of inflammation by SWD. Thursday, 6 January, 2022

18. Effects on muscle tissue Induction Of Muscle Relaxation: When SWD applied over spasmodic muscle in inflammatory and traumatic conditions induces muscle relaxation and reduces pain. Thursday, 6 January, 2022

19. Traumatic conditions The beneficial effects of short wave diathermy on traumatic lesions are similar to those produced in inflammation. The exudation of fluid (followed by increased absorption) and the increased flow of blood through the area assist in the removal of waste products, while the improved blood supply makes available more nutritive materials, so assisting the healing processes. Thursday, 6 January, 2022

20. EFFECT ON healing time The beneficial effect of SWD in traumatic conditions includes fluid exudation, increased blood flow, removal of waste products etc. The increased blood flow makes more nutritive material therefore assist in healing process. Thursday, 6 January, 2022

21. Indications Disorders of the musculo -skeletal system Sprains Strains Capsule lesions Muscle and tendon tears Chronic inflammatory/infective conditions Degenerative joint disorder Thursday, 6 January, 2022

22. Joint stiffness Hematoma Chronic Rhematoid arthritis Tenosynovitis Synovitis Bursitis Sinusitis Carbuncles Abscesses Infected surgical incisions Dysmenorrhoea Frozen shoulder Cervical spondylosis Lumbar spondylosis Thursday, 6 January, 2022

23. CONTRA-INDICATIONS Over Metallic Implants: If there's any metallic implant of the body in the field of SWD, it will cause concentration of the field and will result in destruction of adjacent tissues. Haemorrhagic Areas: The increase in circulation can precipitate haemorrhage . E.g:haemophilia . Over ischaemic Tissues: In, ischaemia , the circulation is unable to disperse the heat that could lead to burns or even gangrene. Over Malignant Tissues: The increase in temperature causes increase in metabolism, which could accelerate neoplastic growth or even lead to metastasis of malignancy. Tuberculous Joints: It may cause spread of infection, thereby leading to joint damage. Impaired Thermal Sensation: Application of a safe level of intensity requires patient's sensitivity to heat. Disturbed and impaired thermal sensation could result in high intensity being applied with consequent tissue destruction. Thursday, 6 January, 2022

24. Unreliable Patients: In very old or very young patients, the cooperation in monitoring the administration of the level of intensity cannot be guaranteed. Excessive Oedema: Non-inflammatory oedema is likely to be aggravated by the administration of any form of heat. Recent Radiotherapy: For a period up to 3 months following therapeutic doses of radiotherapy, skin sensation and circulation is diminished. Hypersensitivity to Heat: When liniment is applied, the circulation increases and if heat is then applied, further increase in circulation may not be possible to disperse the heat. Acute Infection: There may be exacerbation of infection by heat.Eg : in case of osteomyelitis. Cardiac Pacemaker: The intensity of SWD interfere with the functioning of pacemaker. Over Wet Dressings and Adhesive Tape: The heat is more readily absorbed and the field is concentrated on that area. A burn or scald could result. Intra-Uterine Contraceptive Devices (IUCD): Those women using IUCD for contraception should not take diathermy over pelvic region since these are metallic and the field may concentrate, thereby causing tissue damage of adjacent areas. Over Pregnant Uterus: SWD may be harmful to the developing foetus . Venous thrombosis: Heat applied to the affected area may result in formation of embolus. Thursday, 6 January, 2022

25. ADVERSE EFFECT OF SHORT WAVE DIATHERMY BURNS SHOCK Thursday, 6 January, 2022

26. BURNS Short wave diathermy can cause soft tissue burns when used at normal or excessive doses and because the distribution of this type of energy varies significantly with the type of tissue, it can burn some layers of tissue while sparing others. Fat layers are at greatest risk of burning, particularly when plate applicators are used, because they are more effectively heated by this type of muscle or skin and therefore is not cooled as effectively vasodilation. Because water is preferentially heated by all forms of diathermy, the patients skin should be kept dry by wrapping with towels to avoid scaling by hot perspiration. Thursday, 6 January, 2022

27. SHOCK The danger of electrical shock is present in the use of short wave diathermy. In this case, both the patient and the therapist are potentially at risk. Thursday, 6 January, 2022

28. THANK YOU Thursday, 6 January, 2022