16 Flashcards
electrosurgery vs electrocautery
electrocautery: uses electrical current to heat an instrument which is then used to cauterize tissueelectrosurgery: form of energy transfer via electrons from the instrument to the tissues
relationship btwn current, resistance of conductor and voltage
current is directly proportional to voltagecurrent is indirectly proportional to resistance of the conductor
describe monopolar vs bipolar flow
monopolar: Electrosurgical unit or generator sends alternating current flow from generator to hand piece or active electrode–>through patient–>travels back to generator via inactive electrode (grounding or dispersive plate)bipolar:Electrosurgical unit or generator sends alternating current flow from generator to hand piece or active electrode (one prong)–>through patient–>travels back to generator via inactive electrode (inactive prong–dispersive electrode)NO GROUNDING PLATE NEEDED
benefits to bipolar over monopolar
no ground dispersive inactive electrode platemore preciseless lateral thermal damageworks in wet environmentsafer
main causes of electrosurgical injury during laparoscopy
inadvertent touching or grasping of tissuedirect coupling current traveling
T/Fthe larger the contact area of the dispersive grounding plate, the less is the chance of thermal injury
TRUE
what is the degree of tissue injury dependent on when using electrosurgery
- output mode2. power setting3. contact area time4. tissue resistance
at what temperature do proteins begin to denature irreversibly
45 C
electrothermal bipolar sealing devices
LigasureSurgRx Ensealelectrothermal energyprovide hemostasis by denaturing collagen and elastin from the vessel wall and surrounding connective tissue
Ligasure device is approved for use of what size blood vessels
7 mm or smaller in diameter (veins 7 mm, arteries 5 mm)
benefits of bipolar sealing device SurgRx Enseal vs Ligasure
< 7 mm diameter blood vessels (like Ligasure)1 mm limited thermal spreadhot and cold scissorssignificantly higher bursting pressure
comparison of SurgRx Enseal, Ligasure, and Harmonic ACE
Enseal = highest bursting pressures, less thermal damage to adventHarmonic ACE (5 mm vessels, ultrasonic E) = shorter sealing processLigasure = significantly longer sealing process, less thermal damage media
ultrasonic energy systems
harmonic systems HARMONIC ACEuse waves at 55,000 vibration/s to create an oscillating effect vibration induced heat and coagulation cut (center), coat (outer) part of bladeuse lower temps than electrotherm units and use coaptive coagulation (vessels tamponades then sealed with coagulum)
difference in temp btwn electrosurgery/laser units vs harmonic ultrasonic units
electrosurgery/lasers: obliterate coagulation (150-400C)harmonic ultrasound: coaptive coagulation (50-100C)
benefits of harmonic ultrasound over electrocautery
simultaneous cuts and sealslower tempsminimal thermal spreadno charring/dissecation/tissue stickingreduced smoke/improved visualization
3 categories of laser -tissue interactions
- photochemical: chemical reaction induced by light2. photothermal: heat related interactions (ablation/coag)3. photomechanical/ionizing: direct tissue destruction (cell membrane, protein, DNA destruction)
T/Fphoto ablation = tissue ablation
FALSE in lasers, photoablation = breakage of molecular bondsin radiofrequency, tissue ablation = tissue destruction through direct heating/protein denaturation
types of surgical lasers
- argon 2. co23. Nd:YAG4. Ho:YAG5. Excimer laser
depth of penetration by major lasers
excimer < CO2 < argon < diode < NG:YAG
characteristics of argon lasers
488-514 nm wavelength (blue-grn visible light)energy is absorbed by hemoglobin and transformed to heat
Characteristics of CO2 lasers
instantaneously heat intracellular water causing cells to explode10600 nm (infrared)most comparative studies have shown that CO2 laser is NOT superior to electrosurgery
characteristics of Nd:YAG lasers
neodymium: yttrium-aluminum-garnet1064 nm (infrared)deepest penetrationused in most endoscopic procedures
characteristics of Ho:YAG lasers
holmium: yttrium-aluminum-garnet2.1 μm wavelength (TJ says 2.1 nm)Highly absorbed by watervaporize, cut, coagulate and smooth tissue
characteristics of excimer laser
UV laser used in ophtho sx (LASIKS)
safety considerations with lasers
- ocular hazard2. toxic smoke production3. fire hazard4. energy dissipation to adjacent tissues5. mutagenesis6. tissue emphysema/gas emboli
