Electrosurgery Flashcards
(24 cards)
What is electrosurgery?
application of high frequency electric current to biological tissue as a means to cut, coagulate, dessicate or fulgurate tissues
Why doesn’t electrosurgery electrocute people? What is their frequency?
200 kHz - 3.3 MHz
(muscle and nerve stimulation ceases at 100kHz, household appliances etc are 60Hz)
Electrocautery vs electrosurgery
electrocautery (direct current)
- often inaccurately described as electrosurgery
- current doesnt enter pt’s body, only the heated wire tip comes in contact w tissue
electrosurgery (alternating current)
- uses high freq alternating current (AC)
- AC circuit must be completed
Components of electrosurgical (AC) circuit
circuit = flow of current from electrosurgery unit to active electrode to the patient, to the pad and back to the ESU
current - flow of electrons through the electrical circuit
voltage - electrical force pushing current around the circuit, through varying degrees of tissue resistance
resistance - literally tissue being treated, which has varying characteristics
2 main types of electrical waveforms and what they do?
- Sinusoidal (continuous) - for cutting
- Modulated (with resting points) - for coagulation
3 things you must never touch with electrosurgery tip
vital tooth
bone
metal
2 principles about electricity
- always seeks ground
- always seeks path of least resistance
What is surgical smoke?
emissions made by equipment such as lasers and ESUs causing thermal destruction of soft and hard tissue
contain low volume of toxic gases such as benzene, hydrogen cyanide, formaldehyde, bioaerosols and dead and live material (like blood fragments and viruses)
usually insivisble to naked eye
Risks associated with surgical smoke
- unquantified infection risk
- occular and upper resp tract irritation
- visual problems for surgeon
- evidence of mutagenic potential but no evidence of human carcinogenicity
- risks vary according to circumstance - procedure, equipment, technique, patient
How to manage/remove surgical smoke?
- usually achieved by effective local exhaust ventilation (LEV) systems in hospital operating suits
- in dentistry, we use HVE to control plume
- dedicated smoke evacuators use a high efficiency particular air filter (HEPA)
Requirements for operating an ESU?
- equipment complies w Australian standards
- set up equipment in accordance w manufacturer instructions
- attend prelim training courses to attain adequate expertise is requirements
- be aware of potential fire and explosion hazards (e.g. alcohol skin preps, medical oxygen, N2O)
- check equipment for signs of damage (needs regular checked/serviced by licensed electrician)
*
There is potential for alternate site burns when using ESU as electricity always seeks ground. What are some things that must be done to minimise this risk?
- observe skin touching conductive objects like IV poles, metal bed rails etc
- watch for anything touching metal
- check for arms over bedrails, handrails etc
- seperate all wires, including heart monitor wires from active cords and dispersive electrode cords
- CHECK MED HX FOR IMPLANTED METAL AND ELECTRICAL DEVICES (including metal piercings), verbally ask patient as well
What do we do if a patient has jewellery
remove all pierced and non-pierced jewellery
removal helps to avoid burns, avoid accidental injury, lower staff liability
navel and genital jewelry can be in circuit
tongue studs can damage scopes and impede intubation in an emergency
T/F Scarred skin (burns, tattoos, etc) and excessive hair in the area of the dispersive electrode may increase risk of injury
True
Where should the ground electrode NOT be placed? (5)
boney prominences
scar tissue (including tattoos)
skin/scars over implanted metal prosthesis
hairy surfaces - clip if necessary
lotions or oils on skin
T/F Non conductive, plastic hand instruments and evacuation tips are to be used
True
Tips
- reassure patient, ‘electrosurgery’ can instill fear and trepidation while laser doesnt
- ensure profound local anaesthesia is achieved
- set the dial on ‘cut’ in the middle power range to start - reduce it if charring/sparking or increase it if dragging in the tissue
- use a perio probe to measure the pocket depths and mark them externally with a sterile pointy/sharp probe
- ascertain the muco-gingival junction/reflection line (cases with attached gingiva width 1.5mm or less NOT suitable for electrosurgery)
- remove the tissue in shaving action and avoid going deep
- place retraction cord to reduce chance of containing the tooth
- contact tissue no more than 2s at the time with 10s between
- paint on savacol or saline solution to keep the mucosa moist and cool AND as a conductive medium (dry mucosa does not conduct particularly well and tends to cause sparking) / CHX will help with healing
- have the HVE (big suction) remove the smoke as it is being produced
- small electrosurged wounds do not need dressing but larger ones will need a perio dressing like Coe-Pak
To use the optimal characteristics of radiowave surgery, adjacent tissue damage must be limited. What are some variables that contribute to lateral thermal tissue destruction?
- time
- intensity of power
- wave form
- surface area
- frequency
What is electromagnetic interference?
((all electronic devices radiate energy in the form of electromagnetic radiation waves))
- may occur when EM waves from one device interfere with or cause an undesired response in another electronic device
Sources of EMI in healthcare?
- ESU
- defibrillators
- MRI
- PET
- radiation therapy
electrosurgery involves high voltage and high frequency current, it is the most common source of pacemaker EMI and the principle intraoperative issue for a patient with an implanted electronic device due to possibility of current demodulation
What is an IED? Give some examples
implanted electronic devices are battery operated devices placed within the body to treat a physiological defect or replace a sensory function
cardiac = pacemajers, internal cardiac defibrillators (ICDs), ventricular assistive devices (VADs)
neurostimulators = deep brain, spinal cord, vagal nerve stimulators, programmable ventricular shunts
Implantable hearing devices = cochlear implants
Implanted infusion pumps = osteogenic stimulators, gastric electric pumps
What are some safety considerations when using ESU around pacemakers, ICDs and IEDs
- use bipolar when possible
- keep 15cm between active electrode and any EKG electrode
- keep resuscitation equipment at the ready
- have the device clinical support line available
- contact IED manufacturer for specific deactivation recommendations
If we use monopolar circuit instead of bipolar, what should we consider?
- place pad on opposite lower extremity
- use lowest setting possible
- use shortest activation possible
- if ICD is deactivated, re-establish integrity of device post procedure
Unintentional electrical stimulation of the patients nerves and muscles is caused by demodulation of the electrical current. What should we be cautious of?
- loose wires
- broken wire bundles
- defective/broken adaptors
- active cords routinely inspected for breaks
