Therapeutic Heating Modalities

1. Therapeutic Heating Modalities Mohammed Taher Ahmed momarar@ksu.edu.sa Dr.taher_m@yahoo.com Mobile : 542115404 Office number: 2074

2. Objectives • After studying this lecture, the students must be able to; • Define the therapeutic modalities. • Differentiate between methods of heat transfer. • Understand the physiological effects of thermotherapy. • Offer guidelines for use of therapeutic modalities.

3. Outlines • Classification of therapeutic modalities • Methods of heat transfers • Physiological effects of thermotherapy. • Uses (indications ) of thermotherapy. • Contraindications of thermotherapy. • Precautions & dangerous of thermotherapy

4. Therapeutic Heating Modalities • Therapeutic heating modalities are a variety of physical agent used to deliver therapeutic heat, [(1040-1130F)/(40-450C)], aiming to produce physiological reactionthat inducestherapeutic benefits.

5. Classification of Therapeutic Modalities Electromagnetic Energy Modalities Diathermy • Shortwave Diathermy (SWD) • Microwave Diathermy (MVD) , Actinotherapy Modalities • Infrared radiation (IR) • Ultraviolet therapy (UV) • Low level Laser Therapy (LLLT) • Paraffin wax • Hot packs and hydrocollator Acoustic Energy Modalities Ultrasound (US) Extracorporeal Shock wave therapy (E

6. Superficial Heating Modalities Hydrocollator packs, Whirlpool, Paraffin wax, Infrared lamp Fluidotherapy Depths to 0.5-2 cm . Deep Heating Modalities Shortwave diathermy, Microwave diathermy, Ultrasound, Laser Depths to 3-5 cm Classification of Therapeutic Modalities Superficial and Deep heating agents increase the skin temperature within the therapeutic range of 104°F to 113°Fin order to providephysiological effectsfortherapeutic benefite.

7. Classification of Therapeutic Modalities

8. Methods of Heat Transfer • Heat can be transferred to, from, or within the body tissues by: • Radiation • Conduction • Convection • Conversion • Evaporation

9. Conductionis a direct transfer of energy between two objects in physical contact with each other. Energy is transferred from the area of higher temp, to the area of low temp. Ice packs/bags Hot packs Paraffin Ultrasound Methods of Heat Transfer • Rate of energy transfer by conduction is dependent on • Temperature difference between two materials • Thermal conductivity • The total contact area • Tissue thickness

10. Radiationis a direct transfer of energy from higher temperature to lower temperature without the need for an intervening medium. No-contact is made. Shortwave diathermy Microwave Diathermy Infrared Ultraviolet therapy Methods of Heat Transfer Rate of heat transfer Radiations • Intensity of radiation • Size of radiation source • Types of tissue radiated • Distance from radiation source • Angle of incidence

11. Convectionis a transfer of heat through direct contact between circulating medium (air/ water) and another material of different temperature . This is in contrast to heating by conduction, in which there is constant contact medium between objects. Fluid therapy Whirlpools Blood circulation Methods of Heat Transfer

12. Conversionis a conversion of non-thermal form of energy (mechanical, electrical and / or chemical)into heat. Change of one form of energy to another Electromagnetic energy to heat Acoustical energy to heat Heat transfer by conversion does not require direct contact between the thermal agent and the body, however contact medium is required. Ultrasound Microwave Shortwave. Methods of Heat Transfer

13. Methods of Heat Transfer • Evaporation:heat is absorbed by the liquid on the skin surface and cools the skin as it turns into a gaseous state. • Vapocoolant sprays • Alcohol • Sweating

14. Factors Affecting Energy Transfer • Density of Medium • Reflection • Refraction • Absorption • Law of Grotthus-Draper • Cosine law • Inverse Square Law E=Eo/D²

15. Bio-Physiological Response to Thermotherapy

16. I-Hemodynamic Effects • Vasodilatation – Increase in blood flow: • Effect occurs both locally and systemically • Vasodilatation occurs by variety of methods: • Direct action on smooth muscles of the blood vessels by cutaneous thermo-receptors • Indirect activation of spinal cord reflexes • Increasing the local release of chemical mediators. • This phenomenon can be used to increase blood flow to an area where heat is not able to be applied e.g. • Insensate limb • Ulcer on the leg

17. Hemodynamic Effects

18. Heat provides analgesia to relief pain and muscle spasm Elevate pain threshold (closing of gate control mechanism and enhance secretion of endorphins to block pain and free nerve endings). Indirect by reduction of ischemia and muscle spasm . Increase nerve conduction velocity Decrease conduction latency). Change muscle spindle firing rates II-Neuromuscular Effects • Changes in muscle strength • Muscle strength and endurance found to decrease for initial 30 minutes following heat application • Gradually recovers then increases for next 2 hours • Not really used therapeutically but should keep in mind if measuring muscle strength in therapy

19. Increased Extensibility of Collagen (40-45°C ) Increase extensibility of collagen (tendon, ligament, capsule ) resulting in Relaxation of tension, Increase length of soft tissue, Increase ROM Superficial heat alone will NOT alter viscoelastic properties of tissue Heat + Stretch Result = plastic elongation of deeper tissue such as (tendons, ligaments, joint. capsule, fascia ). Factors important determining treatment strategies Temperature elevation (40-45°C ) Time must be maintained for 5-10 minutes. Stretch exercises III-Altered Tissue Extensibility Superficial agents only good for small superficial joints, Deep agents required for deeper large joints, capsules, muscles.

20. IV-Metabolic Effects For every 18°F (10°C) increase in skin temperature “the metabolic rate increased by factors of 2-3” this lead to Increase Metabolic rate Enzymatic activity Capillary permeability Local blood flow due to vasodilatation Cell metabolism (anabolic & catabolic) Increase leukocyte delivery O2 uptake At temps > 133°F, protein, cells and tissues are destroyed.

21. Physiological effects of Heat Application (1-6)-----Local effects (7-9)-----systemic effects (1-3)---- Local effects (4-6)---- systemic effects

22. Use of Thermotherapy Indication:A condition(s) that could benefit from a specific therapeutic modality. Contraindication: A condition(s) that could be adversely affected if a particular therapeutic modality is used. • Precautions: • Applied with special care or limitations. • “Relative contraindications”

23. Indications Subacute or chronic inflammatory conditions Reduction of subacute or chronic pain Subacute or chronic muscle spasm ↓ ROM Hematoma resolution Reduction of Joint contractures Before passive mobilization and exercise General Indications (uses)

24. Contraindications Acute injuries Recent or potential hemorrhage Impaired circulation (Chronic venous insufficiency ) Poor thermal regulation (neuropathic foot/hand) Over or around neoplasms Over or around infected area( General Contraindications

25. Precautions to Thermotherapy • Never apply heat directly to eyes or the genitals. • Never heat the abdomen during pregnancy. • Very young and very old patients. • Mental retard patients. • Cardiac insufficiency. • To areas with metal implants (higher thermal conductivity) • Over area of topical anesthesia or counterirritants have r been applied • Dermatological anomalies.

26. Adverse Affects of Heat Burns due to: • Poor technique • Patients' inability to dissipate or detect heat • Treatment over areas of implanted metal or open wounds Bleeding: In acute trauma or hemophilia Fainting: Due to potential peripheral superficial vasodilatation and decrease blood pressure .

27. MCQ- Questions • 3-Hot packs - Fluidotherapy - Paraffin - Whirlpool - SW Diathermy - US • Therapeutic Dosage • Hemodynamic Effects • Deep Heat Modalities • Types of Thermal Agents 1-Hemodynamic - Neuromuscular - Metabolic • Biophysiological Effects • Metabolic Effects • Neuromuscular Effects • Hemodynamic Effects 2-Increases nerve conduction velocity - increases collagenous tissue extensibility - increases pain threshold - decreases muscular strength • Neuromuscular Effects • Metabolic Effects • Biophysiological Effects • Hemodynamic Effects