RDT Hospital, Dept of Gen Surgery

Electrosurgery

Dr sumanth

Objectives Describe the principles of the ESU and purpose for its use Describe Monopolar & Bipolar ESU’s and associated

equipment Describe the types of dispersive electrodes (grounding

pads) and appropriate use, including proper anatomic placement

Identify special considerations for the use of the ESU

Often “electrocautery” is used to describe electrosurgery. This is incorrect.

Electrocautery refers to direct current (electrons flowing in one direction) whereas electrosurgery uses alternating current.

During electrocautery, current does not enter the patient’s body. Only the heated wire comes in contact with tissue.

In electrosurgery, the patient is included in the circuit and current enters the patient’s body.

“Proper care & handling of electrosurgical equipment is essential to patient and personnel safety.”

“Electrosurgery is used routinely to cut, coagulate, dissect, fulgurate, ablate, and shrink body tissue with high frequency (i.e. radiofrequency) electrical current.”

AORN (2007) Standards, Recommended Practices, and Guidelines

History Lesson

The first electrosurgical unit was developed in 1926 by Dr. Harvey Cushing (a neurosurgeon) and Dr. William Bovie, a Harvard physicist

The name “Bovie” has been associated with electrosurgical units ever since

Electrosurgery Involves using a high-

frequency electric current to cut tissue and coagulate bleeding

The flow of electricity requires a complete pathway (circuit)

System components:

1. Generator (electrosurgical unit)2. Inactive dispersive electrode

(grounding pad)3. Active electrode (“Bovie” pencil)

The electrosurgical generator is the source of the electron flow and voltage.

The circuit is composed of the generator, active electrode, patient, and patient return electrode. Pathways to ground are numerous

but may include the OR table, stirrups, staff members, and equipment.

The patient’s tissue provides the impedance, producing heat as the electrons overcome the impedance.

Frequency spectrum

nerve and muscle stimulation cease at 100,000 cycles/second (100 kHz), electrosurgery can be performed safely at “radio” frequencies above 100 kHz.

An electrosurgical generator takes 60 cycle current and increases the frequency to over 200,000 cycles per second.

At this frequency electrosurgical energy can pass through the patient with minimal neuromuscular stimulation and no risk of electrocution.

Types of ESU Units Monopolar Bipolar(Some ESU units have both monopolar

& bipolar capability)

Monopolar ESU Electrical energy flows from the

generator (ESU unit), to the active electrode (cautery pencil).

The energy then passes through the patient to the dispersive cautery pad, thus completing the electrical circuit.

Monopolar ESU

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Monopolar Modes Cut Coag Blend- produces cutting effect with

hemostasis

cut

Electrosurgical generators are able to produce a variety of electrical waveforms.

As waveforms change, so will the corresponding tissue effects.

Using a constant waveform, like “cut,” the surgeon is able to vaporize or cut tissue. This waveform produces heat very rapidly.

coagulation

Using an intermittent waveform, like “coagulation,” causes the generator to modify the waveform so that the duty cycle (on time) is reduced.

This interrupted waveform will produce less heat.

Instead of tissue vaporization, a coagulum is produced.

blend

A “blended current” is not a mixture of both cutting and coagulation current but rather a modification of the duty cycle.

As you go from Blend 1 to Blend 3 the duty cycle is progressively reduced.

A lower duty cycle produces less heat. Consequently, Blend 1 is able to vaporize tissue with minimal hemostasis whereas Blend 3 is less effective at cutting but has maximum hemostasis.

REM System(renewable energy management systems)

Most ESU units on the market today have REM technology.

REM system continually monitors the heat build-up under the grounding pad

If the system detects excess heat build-up it will shut off the current flow to prevent patient injury

Bipolar Electrosurgery Bipolar electrosurgery uses 2-tined

bipolar forceps One tine of the forceps serves as the

active electrode, and the other tine serves as the return electrode

The electrical current is confined to the tissue between the tines ofThe bipolar forceps

Bipolar Electrosurgery

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Bipolar Surgery A grounding pad is not needed for

bipolar-only cases

ESU Grounding Pads Available in infant & adult sizes Infant size: follow grounding pad

manufacturer’s recommendation for appropriate weight range

NEVER cut a grounding pad to fit a patient, always use the appropriate size pad

Function of the Patient Return Electrode A return electrode

burn occurs when the heat produced, over time, is not safely dissipated by the size or conductivity of the patient return electrode.

Dangerous Return Electrode Contact with Current Concentration

In the case of reduced contact area, the current flow is concentrated in a smaller area.

As the current concentration increases, the temperature at the return electrode increases.

If the temperature at the return electrode site increases enough, a patient burn may result.

Surface area impedance can be compromised by: excessive hair, adipose tissue, bony prominences, fluid invasion, adhesive failure, scar tissue, and many other variables.

Placement of Grounding Pad

When considering grounding placement it is important to know that electric current travels easily through muscular & vascular tissue

Electric current does not travel well through bone, scar or adipose tissue

Best Grounding Pad Site Over a well-vascularized muscle

mass

Avoid placing grounding pad over bony prominences, hairy sites, scar tissue,excess adipose tissue

Grounding pad site Pad site should be free from lotions

or oils

In some male patients it may be necessary to remove hair from the desired pad site using clippers

Placing Grounding Pad Place grounding pad as close to the

surgical site as possible Grounding pad should be placed so

that the entire surface of the pad is in uniform contact with the pad site

Avoid any tenting or gaps where parts of the pad are not in contact with the patient

ESU Safety Inspect machine for frayed or broken

wires before use.

Active electrode wire should be free of kinks

Use lowest setting that is effective

ESU Safety Avoid using the ESU unit as a table-when

doing this setting buttons may be inadvertently changed or liquid may be spilled into machine

If alcohol-containing prep solutions are used (ex: Duraprep, Prevail) allow prepped area to dry completely before using ESU to minimize fire risk

ESU Safety Recommended practice: keep ESU pencil

in non-conductive holder when not in use- this prevents accidental activation

Prep or irrigation solutions should not pool near the grounding pad

Don’t allow ESU pedal to stand in pool of liquid

ESU Safety No part of the patient should be touching

any grounded metal objects (IV pole, Mayo stand, metal surfaces of OR bed)

Electrical current always seeks the path of least resistance—patient might have an alternate site burn where their body is in contact with metal

ESU Safety When surgeon requests that the ESU

setting be changed, audibly repeat new setting

Do not turn ESU activation sound completely off—sound also alerts surgical team to accidental activation of ESU

ESU Safety If it is necessary to change patient

position intraoperatively, always check grounding pad site after patient is re-positioned

If ESU pencil falls below the level of the sterile field, disconnect it from the generator to prevent accidental activation

ESU Safety If there is any suspicion of patient

injury related to the use of an ESU unit: Immediately remove generator from

service, and send to biomed along with the grounding pad & used active electrode

Surgical Smoke

NIOSH (the National Institute of Occupational Safety and Health) and the CDC (Center for Disease Control) have also studied electrosurgical smoke at length. They state:“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.”

Smoke evacuation device

TroubleshootingIf surgeon makes repeated requests to increase

ESU power or complains that the “Bovie isn’t working”:

Check dispersive pad contact

Check all connections

No resolution after taking above steps- change out ESU pad, pencil and/or machine

Special Considerations: Patients with--

Implanted pacemaker Implanted automatic defibrillator Cochlear Implant Implanted Bone Growth Stimulator Body Jewelry Offender monitoring ankle bracelets Orthopedic implants (total hips, etc)

Metal Implants(Orthopedic implants, etc)

Metal is an excellent conductor of electrical current

Any metal between the surgical site and the grounding pad can attract the electrical current, and cause alternate site burns

Pacemakers Bipolar electrosurgery is recommended in

patients with implanted pacemakers who must undergo surgery

If monopolar surgery is required, place the grounding pad on a site where current will be directed away from the heart & pacemaker generator

Implanted Defibrillators Implanted defibrillators should be

deactivated before the surgical procedure, and reactivated immediately after the procedure

After defibrillator is deactivated the ESU can be safely used for the procedure

Cochlear Implants Monopolar electrosurgical instruments

should not be used on the head or neck of patients who have a cochlear implant- damage to the implant or surrounding tissue can occur

Bipolar ESU may be used, depending on type of implant electrodes- contact manufacturer for info

Argon-Enhanced Electrosurgery Also known as “Argon Beam

Coagulator” Combines argon gas with electrical

energy to increase the effectiveness of the electrosurgical current

Argon gas acts as a pathway to carry the electrical current to the target tissue- coagulates tissue without direct contact

References Conmed Corporation Web site:http://www.conmed.com/ Rothrock (2007) Alexander’s Care of the Patient

in Surgery Valleylab Web Site:http://www.valleylab.com/