Therapeutic Heating Modalities PDF

Therapeutic Heating Modalities  Objectives After studying this lecture, the students must be able to; Differentiate between methods of heat transfer. Understand the physiological effects of thermotherapy. Offer guidelines for use of therapeutic heating modalities. Outlines Methods of hea...

Therapeutic Heating Modalities  Objectives After studying this lecture, the students must be able to; Differentiate between methods of heat transfer. Understand the physiological effects of thermotherapy. Offer guidelines for use of therapeutic heating modalities. Outlines Methods of heat transfers Physiological effects of thermotherapy. Uses (indications ) of thermotherapy. Contraindications of thermotherapy. Precautions & dangerous of thermotherapy  Therapeutic Heating Modalities (thermotherapy) Therapeutic heating modalities are a variety of physical agent used to deliver therapeutic heat (40°-45°C), aiming to produce physiological reactions that induces therapeutic benefits.  Classification of Therapeutic Heating Modalities Superficial Heating Modalities Deep Heating Modalities  Hydrocollator packs (Hot  Shortwave diathermy. packs).  Microwave diathermy.  Whirlpool.  Ultrasound.  Paraffin wax. Depths to 3-5 cm  Infrared lamp. Depths to 0.5-2 cm. Superficial and Deep heating agents increase the skin temperature within the therapeutic range of (40°-45°C) in order to provide physiological effects for therapeutic benefits. Classification of Therapeutic Modalities  Methods of Heat Transfer Heat can be transferred to, from, or within the body tissues by: Conduction Convection Conversion Radiation Evaporation  Methods of Heat Transfer Conduction: is a direct transfer of heat energy between two objects in physical contact with each other. Heat is transferred from the area of higher temp, to the area of low temp.  Hot packs  Methods of Heat Transfer Convection is 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 between objects.  Whirlpools  Methods of Heat Transfer Conversion is a conversion of non-thermal form of energy (mechanical, electrical and / or chemical) into 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  Methods of Heat Transfer Radiation: is a direct transfer of heat from material at higher temperature to material at lower temperature without the need for an intervening medium. No-contact is made.  Infrared  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. Alcohol Sweating  Physiological Effect of Heat Systemic Local Effect Effect  Local Effect I Hemodynamic effects II Neuromuscular effect III Tissue Extensibility IV Metabolic effect  I-Hemodynamic Effects A- Vasodilatation – Increase in blood flow:  Vasodilatation occurs by variety of methods: 1. Stimulation of cutaneous thermo-receptors by heat leads to vasodilatation of blood vessels by its action of relaxation on smooth muscles of the blood vessels 2. Increasing the local release of chemical mediators as histamine like substance, bradykinins.  Vasodilatation causes increase in blood flow to the heated area which will lead to  Increase supply of oxygen and nutrients to the heated area.  Increase antibodies to the heated area.  This improve cell function and enhance healing I-Hemodynamic Effects B-Increase fluid dynamics  Heating and increase in blood flow will increase the capillary pressure and permeability which forces edema and metabolic waste products from the area, then these wastes can be drained into the venous and lymphatic systems.  SO, heat leads to increase venous and lymphatic drainage which aids removal of wastes and re- absorption of edema.  II-Neuromuscular effects A- Increased temperature increase nerve conduction velocity of both sensory and motor nerves. B- Reduction of muscle spasm: Elevation of muscle temperature 42 °C has been shown to result in: Decreased firing rate of gamma (γ) fiber which decrease firing of muscle spindle. Increased firing rate of Golgi tendon organ that leads to reflex inhibitory effect of the respective muscles. These changes in nerve firing rates lead to a reduction in the activities of alpha motor neurons and thus to reduction in muscle spasm and relaxation of muscle  II-Neuromuscular effects C- Relieve Pain Local application of heat relieve pain (subacute and chronic) by the following mechanisms: Direct mechanism Activation of spinal gating mechanism through stimulation of free nerve ending (A-beta) leads to blocking the transmission of pain at level of spinal cord. Indirect mechanism: Heat leads to vasodilatation and increase blood flow resulting in reducing pain through:  Increase the oxygen and nutrition supply  Removal of irritant waste products  Re-absorption of edema  Decrease muscle spasm  Improving tissue healing  II-Neuromuscular effects D- Change in the muscle strength  Muscle strength and endurance decrease during the initial 30 minutes after the application of deep or superficial heating agents as a result of change in the firing rate of gamma fiber and Golgi tendon organ.  Beyond 30 minutes after the application of heat, and for the next 2 hours, muscle strength gradually recovers and then increases to above preheating levels.  III-Altered Tissue Extensibility Increased Extensibility of Collagen (40-45°C )  Increase extensibility of collagen (tendon, ligament, capsule ).  So, heating is indicated before stretching or range of motion exercises.  Heat must be maintained for 5-10 minutes.  Superficial heat only good for small superficial joints,  Deep heat required for deeper large joints, capsules, muscles. IV-Metabolic Effects For every (10°C) increase in skin temperature “the metabolic rate increased by factors of 2-3” Increase tissue temperature leads to increase rate of cell metabolism as a result of increase enzymatic activities and biological reactions. Increase in the cell metabolic rate leads to the followings: 1- Increase demand for oxygen and nutrients. 2- Increase amount of wastes excreted from the cell.  At temps > 50°C, protein, cells and tissues are destroyed.  Systemic effects of heating The following systemic effects occurs when the body is exposed to heat: Generalized skin vasodilatation Generalized sweating Increase pulse rate Increase respiratory rate Decrease blood pressure Physiological effects of Heat Application Increased Decreased 1-Joint stiffness 1- Local blood flow 2-Pain 2- Lymphatic drainage 3-Capillary permeability 3-muscle spasm 4-Metabolic rate 4-Muscle strength 5-Flexibility of collagen tissues 5-Blood pressure 6-Respiratory rate 7-Pulse rate (1-5)-----Local effects (1-4)---- Local effects (6,7)-----systemic effects (5)---- systemic effects  Thermoregulation For optimal function of internal organs, temperature of human body is maintained at 37°C. Body temperature is controlled by thermoregulatory center in hypothalamus. When temperature increase by application of heat modalities, the following mechanism are taken to prevent elevation of body temperature:  Increase blood flow to the skin: increase radiation and conduction of heat from the body.  Increase sweat secretion : increase heat loss by evaporation.  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.  Indications (uses) Indications  Subacute or chronic inflammatory conditions  Subacute or chronic pain  Muscle spasm  Tissue healing  Hematoma resolution  Reduction of Subacute or chronic edema  Reduction of Joint contractures  Before passive mobilization and stretching exercise  Contraindications  Unreliable patient  Fever  Acute injuries  Acute Pain  Impaired sensation  Recent or potential hemorrhage  Impaired circulation (Peripheral vascular disease)  Over or around neoplasms  Over or around infected area  Deep venous thrombosis  Metal implants  Open Wound.  Over sensitive organ as eyes or the genitals.  Precautions to Thermotherapy  Never heat the abdomen during pregnancy.  Very young and very old patients.  Adverse Affects of Heat -Burns due to: 1. Poor technique 2. Patients' inability to dissipate or detect heat 3. 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. -Dehydration: Due to prolonged and intensive heat