Thu. Aug 22nd, 2019

ELECTRO SURGICAL UNIT / DIATHERMY

Electro surgical units were first introduced during the early twentieth century to facilitate haemostasis and the cutting of tissue during surgical procedures 
This is achieved by passing normal electrical current via the diathermy machine and converting it into a high frequency alternating current. The HFAC produces heat within body tissues to coagulate bleeding vessels and cut through tissue. At this high frequency of over 300,000 Hz, the nervous system and muscles are not affected when the current passes through the body.

Due to the high risks of injury to both patients and health care professionals which could lead to permanent disfigurement or death,

ESU MACHINE

TYPES OF ELECTROSURGICAL UNIT

There are two different types of electro surgery:

  • MONOPOLAR
  • BIPOLAR.

MONOPOLAR  ELECTROSURGERY

Monopolar electro surgery is the emitance of the high frequency alternating current fromthe diathermy through an active electrode through the patients body tissues andreturned back to the diathermy machine through a return electrode or by using apatient return plate

MONOPOLAR ELECTRODE

BIPOLAR ELECTROSURGERY

Bipolar electro surgery is the passage of the high frequency alternating current fromthe diathermy machine using only the patient’s tissue grasped between a pair ofbipolar forceps, to form a complete electrical circuit within the patient.Bipolar diathermy does not require a patient return pad as both active andreturn electrodes are combined within the forceps .

BIPOLAR CABLE

Electro surgery has three effects on body tissue:

CUT –                          GENERATION OF HEAT DESTROYS TISSUE CELL

COAGULATION –     TISSUE CELLS CONTRACT TO INCREASE NORMAL CLOTTING

FULGURATION –      CELL WALLS DESTROYED THROUGH DEHYDRATION

Each of these processes generates smoke plume which contains:

  • chemical by-products (eg acrylonitrile and hydrogen cyanide) which can be absorbed by the skin and lungs
  • carbonised tissue, blood particles and viral DNA particles
  • Infectious viruses and bacteria have also been noted.

To reduce associated health hazards, specially designed smokeevacuation systems should be used where available and high-filtration masksdonned for all surgical procedures .

BIPOLAR FOOT SWITCH

THINGS TO REMEMBER

  • The Electrosurgical Unit (ESU) should only be used by trained technician.
  • The ESU should be inspected and safety features tested (eg indications, activation of the return electrode sound indicator) before each use .
  • All cables and electrodes must be checked prior to use to ensure insulation is intacts. If Any problems occurs it  must be reported to the Biomedical Engineering department immediately .
  • The volume of the activation sound indicator should be maintained at an audible level
  • The ESU should be mounted on a wheeled stand that is tip-resistant and moves easily.
  • The ESU should not be used in the presence of flammable agents eg, alcohol, tincture-based fluids
  • The ESU should be operated at the lowest effective power setting to achieve the desired effect for coagulation and cutting
  • The ESU cord should be of adequate length and flexibility to reach the appropriate electrical outlet without stress. Any kinks, knots or curls should be removed from the cord before it is plugged into the appropriate electrical outlet.
  • The patient’s skin integrity should be evaluated and documented in the peri-operative care plan before and after ESU use .The type of return electrode used should also be documented in the care plan.
  • The patient’s jewellery must be removed .
  • If two ESUs are used simultaneously during an operative procedure they must have the same technology, eg both are grounded or isolated .

PROCEDURE:

  • The ESU should be protected from spills. Fluids should not be placed on top of the ESU ,don’t keep any mobile phones in the top
  • The return electrode mat should be the appropriate size for the patient’s weight. A paediatric plate should be used for patients under 22kg and an adult plate used for patients over 22kg
  • In most circumstances, only active electrodes recommended by the manufacturer should be used. If an adapter is used, it should be one that is approved by the manufacturer and does not compromise the generator’s safety features.
  • Before the start of the procedure, the technician or the  team must ensure that any part of the patient is not touching any earthed objects such as the trim of the operating table or intravenous (IV) drip stands.
  • Minimal materials between the patient and the return electrode mat must be ensured to prevent any injury to the patient. This includes draw sheets, sliding sheets, blankets, , nappies and any other clothing. A high level of patient dignity must be upheld at all times.
  • Patient positioning devices should be placed under the return electrode mat where applicable.
  • The return electrode mat should not be folded whist in place during surgery or at the end of the list. Storage of the mat should follow manufacturer’s guidelines.
  • If the return electrode mat is faulty or broken, it must not be used. It should be decontaminated and sent to the biomedical engineering department.
  • The return electrode mat should be placed on the operating table prior to the patient’s transfer onto the operating table. As a minimum, one third of the patient’s body should be on the mat .
  • If using a disposable return electrode plate, it should not be placed over:
    a bony prominence
    implanted metal prosthesis
    areas distal to a tourniquets
    scar tissue
    hairy surfaces
    pressure points/areas
  • Extreme care must be taken when using flammable liquids, such as Alcoholic Chlorhexidine or Betadine to prepare the patient. If these chemicals come in to contact with the disposable pad, major burns can occur to the patient. These areas should be dried thoroughly before using electrosurgery .
  • The majority of the return electrode should be positioned as close to the operative site as possible
  • The return electrode should be connected to the ESU prior to draping to ensure adequate contact and then the lead disconnected from the ESU temporarily to allow for the draping of the patient and the positioning of the surgeon
  • The return electrode and its connection to the ESU should be checked if any tension is applied to the cable if the surgical team repositions the patient. The cable should not be wrapped around metal objects, eg theatre table trims.
    Incomplete adhesion of a dispersive electrode may be caused by moisture
  • Return electrodes plates that have been removed from a patients skin should be discarded and a new plate should be applied straight away
  • Return electrodes plates should not be used on children suffering from epidermolysis bullosa. A return electrode mat or bipolar electrosurgery should be used instead

INSTRUCTIONS BEFORE USING ELECTROSURGICAL UNIT:

The power setting should be confirmed verbally between the operator and the user before activation.

  • The power settings are determined in conjunction with the manufacturers written recommendations, patient size and type of procedure
    It is the responsibility of the surgeon to activate the active electrode .
  • Staff should check the entire ESU circuit if the operator requests continual increase in power to identify any incomplete circuitry.
  • If either the monopolar or bipolar equipment falls below the sterile field, it must be disconnected from the ESU and replaced immediately
  • If the return electrode plate detaches from the patient, the surgery must cease until a replacement plate has been administered.
  • The active electrode tip should be easy to clean, securely placed & be single use
  • When not in use the active electrode should be placed in a clean well-insulated holster. It is the responsibility of the scrub practitioner to ensure that the active electrode is holstered when not in use to prevent burns to the patient and staff
  • If patients or staff receive an injury or if there is an equipment failure while an ESU is being used, the ESU, with its active and return electrodes, must be handled in accordance with the recommendations of the MHRA . Device identification, maintenance and service information and adverse event information should be included in the report .
  • Following the final surgical count the single use active electrode tip should be discarded into a sharps bin. This is the responsibility of the scrub practitioner.
    The return electrode plate should be removed carefully to avoid denuding the surface of the skin. If the condition of the skin is acceptable, verbal confirmation should be given to all members of the operating team. The patient’s skin integrity should be evaluated and documented before and after ESU use.
  • Following removal of the electrode, if the child’s skin appears to be damaged, the following should be carried out:
    inform the surgeon
    carry out any prescribed treatment
    record in the child’s health care records
    complete an Incident Report Form
    inform staff in Recovery Room
    it is the surgeon’s responsibililty to inform the child and family.
  • Principles of laparoscopic electrosurgery are the same as normal electrosurgery.
  • Insulated laparoscopic equipment must be used for all laparoscopic procedures.
  • The insulated laparoscopic equipment must be checked to ensure it is intact
  • Ensure that non-insulated metal objects are kept at a distance from an activated active electrode to avoid creating an alternative pathway.
  • Laparoscopic active electrodes which are damaged should not be used.
    Single use laparoscopic active electrodes should not be re-used.
  • Capacitive coupling occurs when alternating current is transferred from an insulated instrument to an uninsulated instrument through a capacitor.
  • To avoid the phenomena of capacitive coupling:
    use a non-conducting trocar
    use a low setting
    if using a metal trocar (in the absence of a non-conducting trocar) ensure there is good contact with the abdominal wall .
    If insulation should fail, the current could pass directly to other metallic objects in the surgical area or inadvertently burn tissues directly. Insulation can fail due to repeated uses, manhandling or using high voltages .

Cardiac patients

  • Staff should take special precautions when using the ESU with patients with pacemakers and automatic defibrillators as the use of the ESU may interfere with the pacemaker’s circuitry
  • Patients with pacemakers should have continual ECG monitoring during ESU use.
    The following additional precautions should be observed for children with pacemakers:
  • Ensure the distance between the active electrode and the dispersive electrode is as short as possible.
  • Keep all ESU cables away from the pacemaker and its leads.
  • Have a defibrillator immediately available for emergencies during surgery.
    Use bipolar where possible.
  • Have a magnet or control unit available.

Patients with cochlear implants

The following precautions should be observed for patients with cochlear implants:
Use bipolar where possible.
If monopolar diathermy is deemed necessary by the surgeon ensure the distance between the active electrode and the return electrode is as short as possible by using an return electrode mat

2 thoughts on “ELECTRO SURGICAL UNIT / DIATHERMY

  1. Hey ..thankyou so much for this information.It is very useful for us..so plz upload more topics related to biomedical…hope a positive response from you..

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