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Therapeutic Heating Modalities

Mohammed Taher Ahmed [email protected]

[email protected] : 542115404Office number: 2074

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.

Outlines

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

Therapeutic Heating Modalitiesthermotherapy

Therapeutic heating modalities are a variety of physical agent used to deliver therapeutic heat, [(1040-1130F)/(400-450 C)], aiming to produce physiological reaction that induces therapeutic benefits.

Classification of Therapeutic Modalities

Shortwave diathermy, Microwave diathermy, Ultrasound, Laser

Superficial and Deep heating agents increase the skin temperature within the therapeutic range of 104°F to 113°F in order to provide physiological effects for therapeutic benefits.

Hydrocollator Hot packs, Whirlpool, Paraffin wax, Infrared lamp Fluidotherapy

Classification of Therapeutic Modalities

Methods of Heat Transfer

Heat can be transferred to, from, or within the body tissues by: Radiation Conduction Convection Conversion Evaporation

Conduction is 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


Rate of energy transfer by conduction is dependent on1. Temperature difference between two materials2. Thermal conductivity3. The total contact area4. Tissue thickness

Radiation is 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


Rate of heat transfer Radiations 1. Intensity of radiation

2. Size of radiation source

3. Types of tissue radiated

4. Distance from radiation source

5. Angle of incidence

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 medium between objects. Fluid therapy Whirlpools (C/C) Blood circulation


Conversion is a conversion of non-thermal (heat) 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.


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


Factors Affecting Heat Energy Transfer

1) Density, thickness , and type of radiating tissues

2) Degrees of Reflection, Refraction, and Absorption3) Law governing radiations (e.g. Grotthus-Draper, & Cosine law)

4) Temperature difference between two materials

5) Thermal conductivity

6) The total contact area

7) Intensity and size of radiation

8) Distance from radiation source 9) Duration of radiation

Bio-Physiological Response to Thermotherapy

Hemodynamic Effects: Vasodilation

Heat provides analgesia to relief pain and muscle spasm

1. Increased pain threshold (closing of gate control mechanism and enhance secretion of endorphins to block pain and free nerve endings).

2. Reduction of ischemia and muscle spasm .

3. Increase nerve conduction velocity

4. Decrease conduction latency).

5. Change muscle spindle firing rates Changes in muscle strength

1. Muscle strength and endurance found to decrease for initial 30 minutes following heat application

2. Gradually recovers then increases for next 2 hours

3. Not really used therapeutically but should keep in mind if measuring muscle strength in therapy

II-Neuromuscular Effects

Increased Extensibility of Collagen (40-45°C ) Increase extensibility of collagen tissues (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

Superficial agents only good for small superficial joints,

Deep agents required for deeper large joints, capsules, muscles.

III-Altered Tissue Extensibility

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.

Physiological effects of Heat Application

(1-3)---- Local effects(4-6)---- systemic effects

(1-6)-----Local effects (7-9)-----systemic effects

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”

General Indications (uses)

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 Contraindications

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(

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.

Adverse Affects of HeatBurns due to:

1. Poor technique2. Patients' inability to dissipate or detect heat3. 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 .

1-Hemodynamic - Neuromuscular - Metabolic

a) Biophysiological Effects

b) Metabolic Effects

c) Neuromuscular Effects

d) Hemodynamic Effects2-Increases nerve conduction velocity - increases collagenous tissue extensibility

- increases pain threshold - decreases muscular strength

a) Neuromuscular Effects

b) Metabolic Effects

c) Biophysiological Effects

d) Hemodynamic Effects

MCQ- Questions

3-Hot packs - Fluidotherapy - Paraffin - Whirlpool - SW Diathermy - USa) Therapeutic Dosageb) Hemodynamic Effectsc) Deep Heat Modalitiesd) Types of Thermal Agents