🔰Alternating current with a frequency between 0.5 and 1 MHz is used.
🔰The cutting function requires a sine wave pattern and the coagulation function requires a damped or pulsed sine wave pattern.
🔰Unipolar (monopolar) diathermy
🔹consists of a small tip where the current density and heating effect is high.
🔹The current flows through the patient to a neutral or patient plate, which is earthed.
🔹The patient plate is large so the current density and heating effect is negligible.
🔰Bipolar diathermy equipment
🔹consists of two tips on a pair of forceps.
🔹The current passes across the field between the two tips to bring about heating.
🔹 No patient or neutral electrode is required.
🔹 is preferable to unipolar if the patient has a cardiac pacemaker or CNS stimulator (spinal cord or deep brain), as the current is kept at the forceps tip and will not be passing through the body.
🔹 This reduces the likelihood of current passing down the pacemaker or stimulator wire and exciting or damaging electrically conductive tissues.
🔹 is used for delicate surgery such as ophthalmic surgery and neurosurgery.
