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.