     ,   -        

      ,  

    ,   - A  -      , ,  . T    ,  -      ,                ,             , ,

     ,   

’    -   ’        -      -

. W  ’       -

Opposite:InSite® Vision technology from Intuitive Surgical and EndoWrist® instruments allows for precise surgical robotic movement with three-dimensional visualization. OCTOBER 2003 The Surgical Technologist 9

235 OCTOBER 2003 CATEGORY 1

Principles of technology 100,000 times per second, as opposed to house- hold current,which cycles at 60 cycles per second. Electrical energy Power is the rate at which the electrical move- The atom is the smallest piece of an element that ment is accomplished and is measured in watts. keeps its chemical properties. An atom is made There are two types of current, alternating up of a nucleus, containing protons, which carry and direct. In AC, or alternating current, the a positive electrical charge, and neutrons, which electrons flow back and forth along a single carry a neutral charge. Electrons, which carry a pathway due to changes in polarity (negative and negative charge, orbit the nucleus of the atom in positive charges). Common, household alternat- valence shells. Electrical energy involves the ing current changes directions approximately movement of electrons from one atomic shell to 60 times per seconds. DC or direct current flows the shell of an adjacent atom. These “moving” in one direction but loses voltage when it travels electrons are called free electrons. When forces through conductors over long distances.AC cur- are introduced that cause electrons to leave their rent, supplied through the hospital’s electrical base atoms and move to adjacent atoms, the power lines, is the most common type of cur- pcharges of the atoms are changed,with those hav- rent used in powering today’s OR technology, ing fewer electrons than protons becoming posi- while batteries, used in some devices, are a good tively charged, and those with more electrons example of DC current. than protons becoming negatively charged. Dur- When electrons flow within current, they fol- ing electron movement, like charges repel each low a path called a circuit. A circuit is created other and unlike charges attract. This electron when the electrical energy flows from and movement is termed electricity.1 returns to its point of origin.Along the way, elec- The greater the number of free electrons tricity may encounter materials that either facil- involved in this electron movement, the greater itate or obstruct this flow. Impedance, also called the conductivity of the substance or material. resistance, is a property of substances that Materials that allow the flow of free electrons obstructs the flow of free electrons. Impedance is are called conductors, and include metals, such measured in ohms and indicates the ease or diffi- as copper, silver, aluminum, and brass, and non- culty in which a current can flow through that metals such as water, salt water, and carbon. substance. As electron flow encounters imped- Materials that inhibit the flow of free electrons ance, heat builds, resulting in the tissue effect are called insulators, and include items such as commonly seen when using the electrosurgical rubber and the plastic casing commonly seen device (ESU/Bovie). It is important to remember surrounding electrical cords. that electricity flows along the path of least resis- Current is a measurement of the rate of flow of tance and will find the easiest route to return to the electrons and is measured in amperes (amps). the ground or its electron reservoir.2 An ampere is a measurement of how much cur- rent is flowing past a given point in a circuit in Mechanical energy one second. Voltage is the force or push that Mechanical energy is the energy found in mov- moves free electrons from one atom to another.It ing objects. Force is any agent that causes a is measured in volts (V) and indicates the change in movement. Speed is a measurement of strength or energy of the electricity.Voltage is how fast an object is moving, regardless of the the force that will cause one amp to flow through direction of that movement.Velocity is the direc- one ohm of impedance or resistance. Frequency tion and speed of an object when moving in a is the number of energy waves that pass through straight line. Acceleration is a change in velocity, a specific point over a specific amount of time. including a change in direction, in speeding up, Frequency is measured in hertz (Hz) or cycles per or in slowing down. Force is the energy that second. Radiofrequency cycles approximately causes acceleration. Friction is the resistance of

10 The Surgical Technologist OCTOBER 2003

movement of one surface as it passes against form, and includes infrared waves and ultravio- another.2 Mechanical energy is utilized to create let waves, both of which are invisible to the the tissue effects caused by use of the Harmonic human eye, and waves of the human visual spec- Scalpel®. trum, including red, orange, yellow, green, blue, Kinetic energy is the energy an object has indigo, and violet.2 while in motion or during activity. Kinetic ener- gy overcomes friction and resistance to produce Technology applications movement. Potential energy is the energy an object has at rest or stores for use when resistance Electrosurgery is lowered or removed.2 Electrosurgery has become an integral part of most surgical interventions. Even with all of the Light energy safety features built into electrosurgical genera- Light energy consists of a series of photons emit- tors, handpieces, and related equipment, the ted by an object both in the form of waves and ESU remains one of the most dangerous pieces particles. Photons are light particles that are of equipment in today’s operating room. Under-

emitted by an electron. They are created when an standing the principles of electricity and cur- FIGURE 1 electron is moved to a higher orbit or valence rent flow will assist in the prevention of inadver- shell and permitted to return to its preferred tent patient injury. The DaVinci® lower orbit or valence shell. The photons gener- Electrosurgery (ESU) involves the use of elec- ated have the same wavelength and waveform as tric current to seal blood vessels, achieving surgical system the original electron. hemostasis, and to cut or dissect tissue. Two The characteristics of light energy that differ- types of current can be delivered by the ESU gen- allows for precise entiate it from other energy forms are reflection, erator: a dampened interrupted current, which refraction, and color. Reflection is the ability to results in tissue desiccation and coagulation, and surgical move- bounce light rays off a particular object. Light an undampened or continuous current, which rays tend to bounce off at the same angle in results in tissue cutting.A blend mode combines ments from a which they were originally sent. Refraction is these two currents in quick alteration, providing the ability to bend or redirect light rays as the both effects simultaneously.3 remote con- light passes through an object. Color is deter- The pathway of current flow in electrosurgery mined by the height and distance of a light wave- begins at the ESU generator. When activated, trolled console.

OCTOBER 2003 The Surgical Technologist 11

of electricity. If the current is concentrated enough, an alternate-site burn may occur. In bipolar ESU, the active and return electrodes are contained within the same delivery device. The current flows from one jaw of the instrument to the opposite jaw of the instrument, thus provid- ing a readily available return to ground pathway and minimizing unintentional tissue contact.4 Electrosurgical generators today are equipped with a monitoring system to assist in the pre- vention of alternate pathway burns. The remote electrode monitoring (REM) return-patient electrode utilizes a divided, disposable return- electrode pad that is able to sense the amount of electrical impedance/resistance at the contact point between the pad and the patient’s body. This sensor will interrupt power delivery if the quality of the contact is compromised. This assures an adequate flow of electricity from the patient to the generator without creating a burn at the pad site. An active electrode monitoring system also permits measurement of the amount of current delivered to the active electrode in comparison to the amount of current returned to the generator. If the difference between the two amounts exceeds pre-set parameters, the generator will shut down and alarm. Capacitance pads, used in place of traditional adhesive patient-return electrodes, consist of a large piece of conductive fabric encased in ure- thane insulating material. The pad, covered with linen, is placed under the patient’s torso area. FIGURE 2 the current flows through a conducting cable to This pad provides a significant area of contact an active or positive electrode, which contacts surface for dispersion of electrical energy over a EndoWrist® the patient tissues at the point of desired effect. large area, dispersing the electrical energy and The current passes through the tissue and preventing electrical burns.5 instruments are returns back to the generator via the patient’s inactive or return electrode. In monopolar ESU, LigaSure™ controlled from a the flow of electricity occurs in one direction, in The LigaSure™ device utilizes electrosurgical that, the active and inactive electrodes are sepa- energy combined with a specially designed remote surgical rated by a significant distance, resulting in the bipolar forcep with inserts. This device delivers need for the electrical energy to pass through electrical current to tissue placed between the console. adjacent body tissues before contacting the jaws of the forcep. The combination of force and return electrode. As electrical current will fol- energy cause the collagen matrix in vessel walls low the path of least resistance in returning to a and connective tissue to reform into a perma- ground, this current pathway may inadvertently nently fused tissue zone. This fusion permits the include tissues that can be damaged by this flow formation of a permanent autologous seal with

12 The Surgical Technologist OCTOBER 2003

minimal sticking, tissue charring, and reduced the tissue protein, forming a sticky coagulum thermal spread into adjacent tissues. A variety that seals blood vessels, or cutting tissue through of delivery forceps lengths, angles, and thick- the process of cavitational fragmentation. This nesses, including the Std, Max,Axs, Xtd, and Pre- friction is created by movement of the scalpel cise™ handpieces may be used in open surgical blade up to 55,500 times a minute. This rapid interventions. The 5 mm Lap and 10 mm Atlas™ movement causes tissue effect without tissue forceps are used for minimally invasive interven- charring and desiccation. The application of this tions.6 technology is achieved using a handpiece with disposable blades, hooks, and/or balls.8 Argon-enhanced coagulation (AEC) The argon-enhanced coagulation system is not Morcellator a laser. This electrosurgical unit utilizes a hand- The morcellator is a mechanical device that frag- piece to simultaneously deliver a stream of argon ments tissue into long strips that can be extract- gas with the electrical current. The current ion- ed through the barrel of the instrument. This izes the gas, leaving a more conductive pathway extraction can be accomplished via a small inci- to deliver the current to the target tissues. The sion during minimally invasive surgery, facilitat- gas conducts the current to the tissues, permit- ing the debulking and removal of benign tissue ting tissue effect without direct active electrode in a reduced time period.9 contact. This “no-touch”technique is invaluable when cauterizing, cutting, or sealing large areas Robotics of non-specific, oozing, friable tissue, such as a The introduction of robotics into the surgical liver or kidney parenchyma. In addition, AEC arena permits the development of surgical appli- produces less smoke and odor, and reduces tis- cations previously restricted by human limita- sue adhesion to the electrode (in cut). Since the tions. The concept of surgical robotics applies electrical energy is delivered using a monopolar three different technologies to enhance the skills handpiece, a patient-return electrode is required of the surgical team. These concepts include the during its application. robotic arm, voice-activated control systems, and remote surgical manipulators. CUSA The robotic arm is a device that manipulates The Cavitational Ultrasonic Suction Aspirator surgical instrumentation under the guidance of (CUSA) consists of an ultrasonic vibrating tip the surgeon (Figure 1). It is used to manipulate used to “break up” and vacuum away tissue. The endoscopic telescopes or, when integrated with sensitivity of the ultrasonic activity can be a remote surgical manipulator and fitted with adjusted to accommodate different densities of surgical instrumentation, to perform dissection, tissue, permitting the skeletonization of vital suturing, and manipulation of internal tissues structures such as blood vessels and the removal and structures. The robotic arms attach to the of density-specific tissues. This technology pro- bed rail of the operating table, permitting them vides rapid, selective tissue fragmentation with to remain in geometric alignment with the sur- quality visualization of the operative site.7 gical patient when the table is repositioned intraoperatively. The robotic arm can be voice- Harmonic Scalpel® controlled by the surgeon using a voice-recogni- The Harmonic Scalpel® delivers ultrasonic tion command system, or hand-controlled by sound waves that simultaneously cut tissues and the surgeon seated at a remote surgical manip- seal blood vessels. Electrical energy is delivered ulator console (Figure 2). The potential exists to a piezoelectric transducer which creates for the surgeon to control the robotic arm from mechanical friction energy capable of coagulat- truly remote sites utilizing the concepts of ing tissue through the process of denaturation of telesurgery.10

OCTOBER 2003 The Surgical Technologist 13

The relationship between physics and medicine Laser Laser is an acronym for light amplification by the Physics principles Medical applications stimulated emission of radiation. Laser light is created when a medium, either gas, solid, liquid Sound waves (frequency and wavelength), Diagnostic ultrasound or semi-conductor, is stimulated or “excited” to speed of sound,acoustic impedance,reflection imaging and Doppler release electrons from their preferred valence of sound waves from interfaces,theDoppler flow;echocardiography shell. Upon return to their valence shell, the elec- effect trons give off photons or light energy. This process is repeated to a point where an intense Principles of light,optics Light microscopy,lasers, beam of light is created. fiber optics Laser light differs from other types of light in that it has unique characteristics, including Atomic physics,light behavior (wave properties, Surgical lasers and photo- coherence, collimation, and monochromatism. frequency,and wavelength,color of tissues), dynamic therapy The coherence of laser light indicates that all of photon energy,the electromagnetic spectrum, the light waves are in phase as they travel in the power,energy,photon energies (emitted or same direction, meaning that they peak and absorbed) trough in the same sequence. Collimation means that the light waves travel parallel to one anoth- X-ray energies and wavelengths,production of Radiography,CT imaging, er rather than in haphazardly crisscrossing path- gamma rays,electromagnetism,energy and PET,and MRI scanners ways. momentum conservation Monochromatism means that the laser light is comprised on only one pure light wavelength. Nuclear physics Radioisotope labeling, This purity permits collimation and coherence nuclear medicine,radia- of the light energy, creating an intense light capa- tion therapy ble of tissue dissection and vaporization. The tissue reaction to laser is referred to as Reflection and refraction,indexofrefraction Fiberoptic scopes radiant exposure. Radiant exposure, or the tissue effect, depends on the absorption of the laser Snell’s Law of Heat,principles of energy and Sterilizers,ultrasonic light by the target tissue, the power settings and power,properties of liquids and gases,sound washers time of exposure to the laser light, and the size waves,vibrations,pressure of the target tissue. When exposed to laser light, tissues may react in one of two ways. The first, Electromagnetism Pacemakers,defibrillators thermal dissolution, occurs when the laser light causes intracellular water to heat, creating steam. Mechanics,power, Robots Since steam in a closed structure generates pres- energy,electromagnetism sure, the cell wall lyses or “explodes”,releasing the steam and carbon in the form of eschar and Reflection and refraction,properties of gases, Minimally invasive plume. The second tissue reaction is called pho- electromagnetism,light properties,pressure surgery todynamic destruction. Photodynamic destruc- tion occurs when the light energy interacts with Sound waves (frequency and wavelength), Cavitron Ultra-Sonic Aspi- chemically-sensitized cells resulting in a disrup- speed of sound,acoustic impedance,reflection rator (CUSA) tion of the cell’s basic metabolic processes, of sound waves from interfaces resulting in cell destruction. Lasers are commonly named by the medium Electromagnetism,power,energy Electrosurgical unit used to generate the laser light. Some of the more common mediums used in the operating room Reprinted from Technological Sciences for the Surgical Technologist.© 2002 AST. setting today include: carbon dioxide (CO2) gas;

14 The Surgical Technologist OCTOBER 2003

yttrium-aluminum-garnet (YAG) crystal, which that promote, support, and incorporate the sur- can be doped with Neodymium (Nd:YAG), gical technologies of the 21st century. holmium (Holmium:YAG), or erbium (erbium: YAG), or Nd:YAG light that is then passed About the author through a potassium titanyl phosphate crystal Ann Marie McGuiness, CST, CNOR, is the OR (KTP); Argon gas; or tunable dye, where the clinical educator at Shawnee Mission Medical color achieved is obtained by changing the com- Center in Shawnee Mission, KS, and was a pre- position of the dye and employing prisms or fil- senter at AST’s 34th Annual National Confer- ters along the light pathway.11 ence in May.

The future References The evolution of technology in the operating 1. Freudenrich CC. How Atoms Work. science. room setting is already evident. Monitors, light howstuffworks.com/atom.htm Accessed 9/11/03 sources, lasers, and computers are but a few of 2. Marshall R and Jacobs D. Physical Science. the technologies used on a daily basis in caring Circle Pines, MN: AGS Publishing; 2001 for the surgical patient. Surgical technique has 3. Ulmer BC. The Valleylab Institute of Clinical evolved to include less and less invasive tech- Education. Electrosurgery Continuing Edu- niques, whenever applicable. The evolution of cation Module. www.valleylabeducation.org/ technology, instrumentation and techniques to esself/index.html Accessed 9/11/03 support minimally invasive surgical applications 4. Electrosurgical Safety Course. Section 2— continues to develop rapidly, barely keeping pace Electrosurgical Devices and Principles. with the demands of the profession. This tech- robo.fe.uni-lj.si/~matijap/bts/electrosurgery/ nology moves the surgical team further from the tissue.htm Accessed 9/11/03 invasive, hands-on patient care of yesteryear. 5. Megadyne 2000 Patient Return Electrodes. As the demand for the support, management, www.megadyne.com/mega2000.htm Accessed 9/12/03 and maintenance of technology increases, the 6. Valleylab. LigaSure™. www.ligasure-usa.com role of the surgical technologist will continue to Accessed 9/12/03 expand. Technologists have the professional 7. Valleylab Product Information. CUSA™ obligation to increase their knowledge base in Ultrasonic Surgery Systems. www.valleylab. the areas of biomedical technology in order to com/productinfo.cfm?menu=product Accessed 9/12/03 understand and troubleshoot electrical circuitry. 8. Johnson & Johnson Harmonic Scalpel®. This, in combination with their specific knowl- www.jnjgateway.com/home.jhtml?loc=USENG&page= edge of surgical interventions and target anato- viewContent&contentId=fc0de00100000325&parentId my and physiology, will allow them to better =fc0de00100000325 Accessed 9/12/03 anticipate the needs of the surgical team when 9. Johnson & Johnson Product Overview. addressing surgical anomalies and unanticipated GYNECARE X-Tract Tissue Morcellator. complications, and to be prepared for expanded www.jnjgateway.com/home.jhtml?loc=USENG&page= roles within the surgical field, including direct viewContent&contentId=edea000100006650&paren- and indirect patient care, to enhance their skills tId=fc0de00100000340 Accessed 9/12/03 sets as human resources in specialty areas 10.Computer Motion. www.computermotion.com become more scarce. Accessed 9/12/03 As the profession of surgical technology con- 11.Alexander’s Care of the Patient in Surgery. tinues to emerge, practitioners need to move Rothrock J, ed. St Louis:Mosby; 2003. beyond the standards of the 20th century and embrace their roles as active members of the sur- gical team with knowledge, skill, and behaviors Images used courtesy of Intuitive Surgical, Inc.

OCTOBER 2003 The Surgical Technologist 15

235 OCTOBER 2003 CATEGORY 1 6. A harmonic scalpel uses which type of energy? a. kinetic CECONTINUINGExam EDUCATION EXAMINATION CEExam 1. Electrons that move between shells b. potential ofatoms are called ___. c. mechanical a. protons d. light b. neutrons c. free electrons 7. In which type of ESU unit are the active d. motorons andreturn electrodes contained within thesame delivery device? 2. Which is mismatched? a. monopolar Technology forthe a. frequency-energy waves b. bipolar b. ampere-current c. neither twenty-firstcentury c. voltage-resistance d. both d. Hertz-amps 8. ___ is designed to provide significant con- 3. Which type of current commonly tact area to disperse electrical energy? Earn CE credit at home powerstechnology in the OR? a. REM You will be awarded one continuing education (CE) credit for a. AC Current b. monopolar ESU recertification after reading the designated article and com- b. BC Current c. LigaSure device pleting the exam with a score of 70% or better. c. DC Current d. capacitance pad If you are a current AST member and are certified,credit d. electrolyte current earned through completion of the CE exam will automatically 9. The light waves of a ___ are all be recorded in your file—you do not have to submit a CE 4. Heat builds when current meets resistance, inthesamephase;they peak and trough reporting form.A printout of all the CE credits you have earned, which is measured in ___. inthesame sequence. including Journal CE credits,will be mailed to you in the first a. hertz a. harmonic scalpel quarter following the end of the calendar year.You may check b. volts b. laser the status of your CE record with AST at any time. c. ohms c. morcellator If you are not an AST member or not certified,you will be d. amps d. CUSA notified by mail when Journal credits are submitted,but your credits will not be recorded in AST’s files. 5. Which is mismatched? 10. Which uses sound wave technology? Detach or photocopy the answer block,include your check or a. acceleration-resistance a. laser money order ($6 for members or $10 for nonmembers) made b. force-change in movement b. harmonic scalpel payable to AST and send it to the Accounting Department,AST, c. velocity-direction and speed c. CUSA 7108-C South Alton Way,Centennial,CO 80112-2106. d. all are mismatched d. b and c

235 OCTOBER 2003 CATEGORY 1

Technology for the twenty-first century abcd abcd

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