Electrosurgical

1. Electrosurgical/Surgical Diathermy Units A Saudi Food & Drug Administration Program January 2008 Tim Ritter Senior Project Engineer Copyright 2007

2. Copyright 2007 Electrosurgical/Surgical Diathermy Units Electrosurgical Basics Electrosurgical Burns Laparoscopic Accidents Injuries to Medical Staff Fires

3. Copyright 2007 Some Basic Electrosurgery Facts Used in about 80% of all surgical procedures Very effective surgical tool Cutting Coagulation Fulguration Not well understood by clinicians Commonly seen in FDA and ECRI problem reporting databases Cutting Typically, small-surface active electrode tip (e.g., needle, wire loop, edge of flat blade) Initially applied (in contact) with target tissue Sufficient amount of steam from vaporized tissue separates electrode from tissue Sparks through vapor layer between active electrode and tissue carry cutting current Relatively low voltage compared to coagulation Contact coagulation (dessication) Direct contact between active electrode and target tissue Results in vaporization of cellular water, denaturation of protein, and drying of tissue Achieved with broad surface active electrode tip and low-voltage mode Produces white coagulum Frequently misapplied for cutting and dessication Arcing (Fulguration) Arcs (sparks) char bleeding tissue surface Intensely concentrated current at small points on tissue surface Active electrode tip held slightly above bleeding tissue surface Produces black coagulum High-voltage mode Greatest potential for interference with other medical devicesCutting Typically, small-surface active electrode tip (e.g., needle, wire loop, edge of flat blade) Initially applied (in contact) with target tissue Sufficient amount of steam from vaporized tissue separates electrode from tissue Sparks through vapor layer between active electrode and tissue carry cutting current Relatively low voltage compared to coagulation Contact coagulation (dessication) Direct contact between active electrode and target tissue Results in vaporization of cellular water, denaturation of protein, and drying of tissue Achieved with broad surface active electrode tip and low-voltage mode Produces white coagulum Frequently misapplied for cutting and dessication Arcing (Fulguration) Arcs (sparks) char bleeding tissue surface Intensely concentrated current at small points on tissue surface Active electrode tip held slightly above bleeding tissue surface Produces black coagulum High-voltage mode Greatest potential for interference with other medical devices

4. Copyright 2007 Basic Principles of Electrosurgery Current conducted through a complete circuit including the generator, insulated cables, electrodes, and the patient Frequency Typically operate at frequencies between 300 KHz and 1 MHz 300 kHz to 1Mhz avoids complication of electrical nerve stimulation Under certain conditions (e.g., arcing between two dry metal surfaces) low frequency components (<10 KHz) can be introduced with the delivered electrical current Frequency Typically operate at frequencies between 300 KHz and 1 MHz 300 kHz to 1Mhz avoids complication of electrical nerve stimulation Under certain conditions (e.g., arcing between two dry metal surfaces) low frequency components (<10 KHz) can be introduced with the delivered electrical current

5. Copyright 2007 Monopolar Electrosurgery

6. Copyright 2007 Bipolar Electrosurgery Current conducted between two electrodes on the same instrument (e.g., forceps) Dispersive return electrode is not needed Current is confined to target tissue at the surgical site between the two electrodes Allows for lower output power than monopolar electrosurgery Generally safer than monopolar electrosurgery – but procedures are often performed on more “delicate” tissue Current conducted between two electrodes on the same instrument (e.g., forceps) Dispersive return electrode is not needed Current is confined to target tissue at the surgical site between the two electrodes Allows for lower output power than monopolar electrosurgery Generally safer than monopolar electrosurgery – but procedures are often performed on more “delicate” tissue

7. Copyright 2007 Electrosurgery Safety Features Continuity Monitor Verifies that a return electrode is connected to electrosurgical unit Cannot detect if return electrode is disconnected from or in poor contact with the patient

8. Copyright 2007 Electrosurgery Safety Features Return Electrode Contact Quality Monitor (RECQM) Offers better level of protection than continuity monitor Assures that good contact exists between the dispersive electrode and patient ECRI strongly recommends using electrosurgical units with RECQM

9. Copyright 2007 Dual Plate Return Electrodes Single-foil return electrodes must not be used with RECQM safety feature Dual-foil return electrodes must be used with RECQM Return electrode site should be properly prepped prior to placing on patient Area should be shaven to remove excess hair and cleaned to provide optimal electrode-patient contact Electrode should be properly oriented on patient with respect to surgical site Single-foil return electrodes must not be used with RECQM safety feature Dual-foil return electrodes must be used with RECQM Return electrode site should be properly prepped prior to placing on patient Area should be shaven to remove excess hair and cleaned to provide optimal electrode-patient contact Electrode should be properly oriented on patient with respect to surgical site

10. Copyright 2007 Electrosurgical Accidents Skin Burns Fires, Explosions Prepping Solutions, Surgical Drapes, Bowel Gas Oxygen-Enriched Atmosphere Active Electrode Arc or Spark Too Much/Too Little Power Delivered Organ Perforations

11. Copyright 2007 A Misconnection Problem See Hazard report: monopolar activation more power than expected bowel perforationSee Hazard report: monopolar activation more power than expected bowel perforation

12. Copyright 2007 Electrosurgical Accidents Argon Beam Coagulators Gas Embolism Interference (EMI) ESU as “Source” of EMI User Injuries Hand sensation Alternate pathways Hand sensation: mostly during urologic procedures (TURP) capacitive coupling of instrument handle Wet environment startle injuries Only 2 cases in US history of “muscular degeneration due to ESU. There is not enough current to cause extensive injury. History of use does not support MDs’ contention.Hand sensation: mostly during urologic procedures (TURP) capacitive coupling of instrument handle Wet environment startle injuries Only 2 cases in US history of “muscular degeneration due to ESU. There is not enough current to cause extensive injury. History of use does not support MDs’ contention.

13. Copyright 2007 Electrosurgical Injuries Return Electrode Issues Poor electrode placement Lack of skin prep Complete or partial removal of return electrodes Skin reactions to adhesives “Edge effects” High electrosurgical currents and long activation times

14. Copyright 2007 Electrosurgical Injuries Active Electrode Issues Insulation surrounding conductive shaft Breakdown Repeated Sterilization Cuts, Nicks, Abrasions Capacitive Coupling Electrical current induced by means of capacitance to other instruments or tissues Inadvertent activation!

15. Copyright 2007 Electrosurgical Injuries Active Electrode Organ Perforations Alternate Site Burns (Use a Holster!) Laparoscopic Active Electrodes Laparoscopic Cannula Burns Failure to Use Activation Tone

16. Copyright 2007 Active Electrode Accidents Inadvertent activation of the ESU due to unintentional switch activation User places active electrode on the patient or the surgical drape between intended activations Safety holster not used Audible activation tone volume is set too low Insulation failure along shaft during procedures, such as tonsillectomy causing burn to tissue inside mouth or to lip User makes direct contact with nontarget tissue

17. Copyright 2007 Electrosurgical Injuries Return Electrode Poor Site Preparation Poor Application technique Non-uniform Conductivity Repositioning Patient Electrode

18. Copyright 2007 Return Electrode Accidents Burns Use of electrolytic (conductive) distention/irrigation media during TURP Conductive solution may render electrosurgery less effective Disperses current away from intended surgical site Lower surgical effect may lead user to increase power output of ESU Conductive solution lowers impedance at active electrode, elevating current Increased power and lower impedance increases current through dispersive return electrode

19. Copyright 2007 Laparoscopic Electrosurgery Monopolar vs. Bipolar Current leakage though cannula Insulation breakage Fire

20. Copyright 2007 Laparoscopic Injuries Inadvertent tip to tissue contact Insulation failures Capacitive coupling Trocar insertion sites Device interference Resulting in bowel perforations, excess bleeding, damage to nontarget tissue, etc.

21. Copyright 2007 ESU-caused Fires Heat, sparks, flaming gases Rarely a device failure – “a known complication”