Greek words therma, meaning heat, and dia, meaning through. The therapeutic generation of local heat in body tissues by high-frequency electromagnetic currents. 1000 deg C Current 500mA
PHYSICAL Moderate heat directly to pathological lesions in the deeper tissues of the body Shortwave Ultrasound Microwave – radar waves
SURGICAL Cauterize blood vessels Destroy neoplasms, warts and infected tissues.
Source of electron flow and voltage CIRCUIT1.Generator2.Active Electrode3.Patient4.Patient return Electrode
60Hz - House hold Appliances 100KHz - Nerve and Muscle Stimulation ceases 200KHz-3.3MHz Electrosurgery 550-1550KHz - AM radio 54-880MHz - Television
Both Active electrode and return electrode functions performed at site of surgery – 2 tines of forceps Tissue grasped is included in electrical circuit.
Active electrode in surgical site Patient return electrode – electrical plate – attached elsewhere. Current flows through patient Localised heating at tip of instrument Minimal heating on plate as more surface area
CUTTING – Continuous current Sinus wave form more heat cell water vaporized COAGULATION – interrupted pulses of current square wave form less heat dessication & sealing of vessels BLEND - Combination of cutting and coagulation waveforms to increase the degree of haemostasis during cutting.
Waveform Power setting Size of electrode Time Manipulation of electrode Type of tissue Eschar
interfere with pacemaker function Superficial burns if use spirit based skin preparation Diathermy burns under indifferent electrode if plate improperly applied Channeling effects if used on viscus with narrow pedicle (e.g. penis or testis)
circuit is completed not by the ground but by the generator recognizes the patient return electrode as the preferred pathway back to the generator If the circuit to the patient return electrode is broken, an isolated generator will deactivate the system because the current cannot return to its source.
So protection from alternate site burns but not from return electrode burns
Choose: Well vascularized muscle mass Avoid: Vascular insufficiency Irregular body contours Bony prominences
Instant Response Technology Measures and provides instant response to changes in tissue impedance/resistance at the electrode contact site consistent tissue effect as demonstrated by a high Power Efficiency Rating (PER) Controls maximum output voltage
Vessel Sealing Technology combines pressure and energy to create a seal. The seals have been proven to withstand more than three times normal systolic blood pressure.
Direct coupling: active electrode is near another metal instrument :gets energized Insulation Failure: coagulation waveform - high in voltage. This voltage or “push” can spark through compromised insulation. Can “blow holes” in weak insulation. So use Cutting current in direct contact with the tissue for coagulation
Inspect insulation carefully Use lowest possible power setting Use a low voltage waveform (cut) Use brief intermittent activation vs. prolonged activation Do not activate in open circuit Do not activate in close proximity or direct contact with another instrument
Use bipolar electrosurgery when appropriate Select an all metal cannula system as the safest choice. Utilize available technology, such as a tissue response generator or an active electrode monitoring system, to eliminate concerns about insulation failure and capacitive coupling.
created when tissue is heated and cellular fluid is vaporized by the thermal action of an energy source. Viral DNA, bacteria, carcinogens, and irritants are known to be present
“Research studies have confirmed that this smoke plume can contain toxic gases and vapors such as benzene, hydrogen cyanide, and formaldehyde, bioaerosols, dead and live cellular material (including blood fragments), and viruses.”
attached directly to a standard electrosurgical pencil
“The ESU should not be used in the presence of flammable agents Avoid oxygen enriched environments Use of a nonconductive holster Use manufacturer approved insulated tips
Cords not be bundled together Cords not be wrapped around metal instruments