Shortwave Diathermy Overview

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Questions and Answers

What is the primary physiological effect of shortwave diathermy?

Remove waste products (correct)

Decrease blood flow

Promote muscle spasms

Increase tissue stiffness

Which of the following is NOT a contraindication for the use of shortwave diathermy?

Patients with metallic implants

Pregnancy

Severe cardiac abnormality

Recent exercise (correct)

What is the frequency commonly used in shortwave diathermy?

30 MHz

27.12 MHz (correct)

50 MHz

15.12 MHz

Which method of shortwave diathermy primarily uses an electrical field?

Capacitive Method Signup and view all the answers

Which of the following is a potential danger of shortwave diathermy?

Burns from excess current Signup and view all the answers

What effect does shortwave diathermy have on muscle spasm?

Reduces inflammation Signup and view all the answers

What is one of the secondary physiological effects of shortwave diathermy?

Increased circulation Signup and view all the answers

How does heat from shortwave diathermy affect areas with impaired arterial blood supply?

Increases risk of gangrene Signup and view all the answers

What technique is most effective in increasing skin temperature?

Co-planner technique Signup and view all the answers

How does the distance between capacitive plates and the skin affect heat perception?

Closer distance increases heat sensation Signup and view all the answers

What is the result when electrodes are placed over areas of thick subcutaneous fat?

Fat tissue heats more than muscle Signup and view all the answers

What should be considered regarding the size of electrodes in relation to the structure being treated?

Electrodes should be larger than the structure Signup and view all the answers

What happens if electrodes are smaller than the diameter of the limb being treated?

Lines of force bend towards the limb Signup and view all the answers

Which technique involves the transverse application of electrodes?

Contra-planner technique Signup and view all the answers

What is a consequence of using electrodes that are too large for the structure treated?

Wasted electrical energy Signup and view all the answers

What is a general guideline for positioning capacitive plates?

Distance should be at least as great as the plate's diameter Signup and view all the answers

Study Notes

Shortwave Diathermy

Therapeutic modality that uses high-frequency alternating currents to generate heat in body tissues.
Commonly used to produce deep heating in joints and soft tissues with a frequency of 27.12 MHz.

Physiological Effects

Primary (thermal):
- Increase circulation
- Increase blood flow
- Remove waste products
- Decrease pain
- Decrease tissue stiffness and muscle spasm
Secondary (non-thermal):
- Tissue regeneration
- Improves tissue metabolism

Indications

Reduces pain and inflammation
Improves range of motion
Reduces muscle spasm and stiffness
Promotes healing in the affected area

Contraindications

Patients taking blood-thinning medications
Severe cardiac abnormality
Cancer
Blood pressure abnormality
Severe/excessive edema
Anesthetic area
Metallic implant
Tuberculosis
Cardiac pacemaker
Reproductive organs
Over wet dressing
Infected open wound
Impaired thermal sensation
Recent radiotherapy
Pregnancy

Shortwave Diathermy Modes

Continuous: Constant application of shortwave energy, used for deep and sustained heating.
Pulsed: Shortwave energy delivered in pulses, used for superficial heating and pain management.

Shortwave Field Types

Capacitive Method:
- Electrical field more than magnetic field
- Uses air space electrodes (flexible pads)
- Common for reducing inflammation, decreasing pain, and increasing tissue temperature.
Inductive Method:
- Magnetic field more than electrical field
- Uses drums (diplode-monode), coils, and sleeves
- Often used for tissue healing.

Dangers of Shortwave Diathermy

Burn:
- Caused by:
  - Concentration of electric field
  - Use of excess current
  - Hypersensitivity of the skin
  - Impaired blood flow
  - Leads touching the skin
Overdose:
- Increases symptoms, pain, and acute inflammation within a confined space. Reduce intensity of subsequent applications.
Precipitation of gangrene:
- Heat accelerates chemical changes and metabolic processes in tissues, increasing oxygen demand which can lead to gangrene.
- Never apply heat directly to areas with impaired arterial blood supply.
Electric shock:
- Can occur if contact is made with the apparatus circuit with the current switched on, but modern apparatus usually prevents this.

Capacitive Field Application Techniques

Co-planner technique:
- Most effective at increasing skin temperature
- Slowest temperature decay
- Electrodes positioned at an adequate distance
- Closer electrodes = greater surface heat sensation
- As distance increases, heat perception decreases
- Adjust distance to control tissue heating
- Closer pads = more superficial heat
- The distance between any parts of the two plates should be at least as great as the plate's diameter.
- Avoid placing plates over areas of thick subcutaneous fat (fat heats more than muscle).
Contra-planner technique:
- Transverse application
- Longitudinal application
- Cross-fire technique
Electrodes size and position:
- Electrodes should be larger than the structure being treated.
- Electric field tends to spread, resulting in lower density in deep tissues than superficial tissues.
- Large electrodes ensure the structure is in the central part of the field.
  - For trunk, use large electrodes
  - For limbs, electrodes slightly larger than the limb diameter
- If the limb's diameter is smaller than electrode diameter, the lines of force bend towards the limb.
- If the limb's diameter is larger than electrode diameter, the lines of force spread, heating superficial tissues more.
- If electrodes are much larger than the limb, some lines of force bypass the limb, wasting energy.

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Description

Explore the therapeutic modality of shortwave diathermy, which utilizes high-frequency alternating currents to generate heat in body tissues. This quiz covers its physiological effects, indications, and contraindications, providing a comprehensive understanding of its applications in physical therapy.