Diathermy

Definition

  • Use of high-frequency electrical current to produce heat.
  • Utilizes an alternating current (AC).

Current Strength

  • Mains Electricity: 50 Hz
    • Causes intense nerve and muscle activation.
  • Diathermy: 300 KHz – 3 MHz
    • Stronger current avoids muscle and nerve activation.

Types of Diathermy

Monopolar Diathermy

  • Active Electrode: Tip of the instrument.
  • Indifferent Electrode: Plate placed on the patient.
  • Current Flow: Passes through the patient.
  • Heat Generation:
    • Intense heat at the instrument tip.
    • Minimal heat at the plate.
  • Burn Prevention:
    • Use a large surface area plate.
    • Place over a large muscle mass.

Cutting Diathermy

  • Continuous current is used.
  • Waveform: Sinusoidal.
  • Effect:
    • Tissue is vaporized.
    • No coagulation occurs.

Coagulation Diathermy

  • Intermittent current is used, allowing time for coagulation to occur.
  • Waveform: Square.
  • Frequency: 50 per second (10% of continuous waveform).
  • Effect:
    • More surrounding tissue damage if used for cutting.

Bipolar Diathermy

  • Current Path: Passes between the tips of the instrument, not through the patient.
  • Safety:
    • Safe for use in patients with pacemakers.
    • Points of forceps must be separated for current to pass.

Risks and Complications of Diathermy

  1. Pacemaker Interference: Use bipolar diathermy.
  2. Arcing: Can occur with metal implants (place plate away from metal).
  3. Flammable Skin Prep:
    • Burns can occur if pooling or soaking of drapes happens.
  4. Improper Plate Application:
    • Concentrates current, leading to burns.
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