ELECTRO -SURGERY SAFETY AND

MANAGEMENT

YA N A M A L A V I J AY R A JM T E C H I N C L I N I C A L E N G

I I T M A D R A S & C M C V E L L O R E & S C T I M S T

ELECTRO-SURGERY

• Electrosurgery is the application of a high-frequency electric current to biological tissue as a means to cut, coagulate, desiccate, or fulgurate tissue.

PRINCIPLE• Having an understanding of the principles of electricity is a strong

foundation for best practices in electro surgical patient care.

• PRINCIPLE:Electrosurgical equipment and accessories facilitate the passage of high frequency oscillating electric currents through tissue between two electrodes to fulgurate desiccate or cut tissue.

GENERATOR IN ELECTRO-SURGERY• In surgery the generator converts electricity to high frequency waveforms

and creates voltage for the flow of the electro-surgical current. 60 cycle current, commonly used in household is increased to over 30,000 cycles per second by generator.

PURPOSE OF GENERATOR

• Pulsating electrical current e.g. d.c. pulses or low-frequency currents (including mains supplyfrequencies) have a stimulating effect on nerve and muscle cells.

• With high frequency alternating currents (> 200 kHz), the physiological system can nolonger follow the stimulation impulse. An insensitivity to stimulus develops.As a result, HF electrosurgical instruments are operated at a base frequency of > 300 kHz.

REGULATING THE THERMAL EFFECT

Regulating the thermal effect through:

1. Current and output power

2. Modulation level

3. Shape of electrode

4. Condition of active electrode

5. Cutting speed and duration of action

6. Tissue properties

MODULATION LEVEL

• This is understood to mean the wave form of the high frequency current produced by a particular generator design and instrument setting.

• There is a number of different designs on the market resulting from the difference in the specific data gathered by the various companies.

• The modulation level can for example be a parameter for the aggressiveness of an electricalincision, but it can also be for the depth of penetration in a coagulation procedure.

ELECTRODE SHAPE• The designed shape of the active electrode is the final determinant for the

field concentrationat the point of application.

• It enables the temperature in the immediate vicinity, and with it the resulting effect, to be regulated. Thin, point-shaped electrodes create a high current density and therefore a high temperature. The result is an electric cutting effect.

• Larger surface electrodes create a lower current density and thus a lower temperature and produce a coagulation effect.

CONDITION OF THE ELECTRODE• According to Joule's law of thermodynamics, the effects are proportional to

resistance. • In addition to the physical resistance already described, the electrode

contact resistance, i.e. an electrode on which coagulate has already formed, increases the resistance of the system enormously.

• With an unchanged instrument setting and unchanged time, the resulting effect willtherefore be considerably reduced. This being so, a contaminated electrode must always becleaned during the course of the procedure.

TISSUE PROPERTIES• As has already been mentioned, physiological tissue varies in its resistance

properties. Theseproperties are expressed physically by the specific resistance R0

Reference: Electro surgery manual, KLS MARTIN group

EFFECTS OF CURRENT• Temperatures above 45°C cause a breakdown in the structure of living tissue

and disruption ofthe function of protein molecules. The process is referred to as denaturation. The origin is athermal effect.

• Coagulation:Temperatures of 60 – 70°C in the area around the active electrode lead to a

slow boiling of the intra-cellular fluid through the cell membrane. As a result of this effect, the cell shrinks and several cells link up to form

chains. A "welding effect" is initiated which stops the bleeding.

EFFECTS OF CURRENT• Electrotomy:Temperatures of above 100°C in the region around the active electrode lead

to the rapidevaporation of the fluid within the cell membrane.

As a result, the cell membrane ruptures forming vapor around the electrode which in turn involves other cells lying in the path of the electrode as it moves.

Electrotomy thus cannot be compared to a mechanical cutting process.

• Mixed currentsThe basic effects of coagulation and electrotomy can now be combined into

so-called mixedcurrents, that have different characteristics.

The instrument thus provides such facilities as reduced haemorrhage incision, or cutting with intense scab formation.

MONOPOLARActive electrode at surgical site,

Return electrode at another site,

Current flows through the body,

Tissue effect takes place at a single active electrode and is dispersed(circuit completed) by a patient return electrode,

BIPOLAR Active and return electrodes within the

instrument,

Current flows confined to tissue between electrodes,

Current flows is limited and is contained in the vicinity of the two electrodes,

As current passes through the tissue from one electrode to the other the tissue is desiccated and the resistance increases, As resistance increases current flow decreases,

ELECTROSURGICAL GENERATORS

•Ground referenced generators (typically older outdated units)• Isolated generators (today’s state of art technology)

GROUND REFERENCE GENERATORS

• Current passes through the patient and returns to the generator, which is linked to the ground.

• Current can go to any grounded object(ECG electrodes, bed, metal objects) other than pad and cause alternative site burns.

• If dispersive pads is forgotten, or not in contact in patient, it still sends currents to and through active electrode which ultimately leads to alternative site burns.

ISOLATED GENERATORS• Alternate burn sites essentially eliminated.• Isolated generators isolate current from ground and don’t allow significant

current to seek alternative pathways.• The current must return through dispersive pad to generator.

ISOLATED GENERATORS LIMITATIONS• If only a small portion of patient sticky return pad is in contact, or if

conductivity of pad is hampered, pad site burn can occur.• This limitation lead to development and incorporation of RECQM system for

sticky pads and Megasoft technology.

PATIENT RETURN PADS

• Patient return pad in monopolar electro-surgery functions as a pathway to the current back to generator.

• Pads are sticky, that has adhesive edge that holds it directly to the patient.• Pads must be large enough to keep current density low as electrical energy

exist in the patient.• If contact area is reduced, or pad is too small, or not in proper contact, heat

builds up and results in burns under pad,• Excessive hair, bone prominences, fluid, scar, adipose tissue, prosthesis are

some of situation that can interfere with dispersive needs.

RECQM (RETURN ELECTRODE CONTACT QUALITY MONITORING SYSTEM)

• Generator has micro-processor that monitors the quantity and the quality of the contact that pad makes with patient.

• They have split foil surface as opposed to large single sheet of foil on the pad.

• If pad contact is interrupted, generator alarms and de-activates.

RISKS ASSOCIATED WITH ELECTR0-SURGERYTechnical deficiency

Unwanted high frequency burning

Incorrect operation

Defective accessories

Ignition of flammable fluids and gases

Risks from improper combination with other equipment

APPLICATION OF THE NEUTRAL ELECTRODE

Full face, durable placing of neutral electrode Application ensuring full contact of neutral electrode Keep natural electrode surface free of soiling and residue Avoid bony protrusions Avoid scar tissue Avoid implants Ensure non slip applications Shave strong hair growth with alcohol Position neutral electrode as close to operating area as possible Avoid moisture

If it is not possible to position the neutral electrode properly, the monopolar technique must be avoided and a bipolar technique used in its place.

TECHNICAL SAFETY WHEN APPLYING THE NEUTRAL ELECTRODEPlug connections properlyRestricted used in coronary region Observe ECG/EEG electrodes and other electrodesProper position of applicationObserve application regulationsCorrect cable placements

a. cable not touching the patientb. cable run as short as possiblec. avoidance of cable coilingd. cable not touching other conductors e.g. ECG cablese. patient not lying on the cable

HIGH FREQUENCY BURNThis type of patient injury concerns unwanted burning beneath the neutral electrode. This is probably the result of two factors:The application area was not shaved although obviously necessary.Residual moisture (probably disinfectant) has obviously been trapped

between the surface of the skin and the electrode.

The HF energy flowing towards the neutral electrode passed through the conducting fluid bridge with a low electrical resistance.

This led to a concentration of current density at these points and hence to burning.

CORRECT PATIENT POSITIONINGWhen employing electrosurgical apparatus, it is crucial

that the patient be placed on an insulating operating table cover, and on a dry, absorbent, water-proof sheet.

All conducting surfaces and contact points, like arm rests and foot supports, must be insulated from the patient.

Care should be taken to ensure that the extremities and the trunk are insulated from each other.

When using liquids, like disinfectants for example, they must not be allowed to moisten dry sheets.

Pools of moisture must be suctioned off rapidly and completely.

CORRECT OPERATION OF EQUIPMENTElectrosurgical systems are the medical products that entail risks.Before operating operator should have received instructions on handling

the equipment..Equipment should be used in proper condition and working order. Improper and un-interrepted activation is hazardous and forbidden.Surgical handle must not be put down with other instruments.Used only in rooms that comply with relevant technical requirements

relevant statuary requirements and technical regulations.

HANDLING FLAMMABLE LIQUIDS AND GASESWhen using electro-surgical equipment, sparking may occur.When using anesthetic, skin cleansing, degreasing and disinfectant agents

there is danger that spark created can cause ignition.The possibility of an explosion is an extreme potential danger for all those

present.

UNINTENDED BURNS BY ACTIVE ELECTRODEUnintended burns are the least understood and most dangerous hazards insurgery. A patient may be burned in three ways:

Insulation failureUnintended burns at the active electrode site (direct coupling),Unintended burns at an alternate site (capacitive coupling).

DIRECT COUPLING• It occurs when active electrode touches another metal.• Electric current flows active electrode to another metal and leads to un-

intended burns in tissues.• Best way to avoid this risk is to refrain from activating active electrode until

the intended tissue is in field of vision and the electrode is in direct contact with tissue and not in contact with any other metal object.

INSULATION FAILURE

• It occurs when the insulation cover of active electrode is damaged.• Cracks or breaks in shaft’s insulation system can allow current to escape

and burn un-intended tissue.• Most damage to insulation occurs during instrument processing, and

specially during sterilization.• Heat with subsequent cooling causes the insulation to shrink and then

expand, which causes cracks and breaks.

CAPACITIVE COUPLING • It is a natural occurrence that can happen when the energy is transferred

through intact insulation to conductive materials.• The current leaks from conductor through insulator to another coductor

STANDARDS OF PRACTICE FOR USE OF ELECTROSURGERY • AST• IEC 60601-2-2• AORN