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57 Cards in this Set
- Front
- Back
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What is Ohm's law used to predict?
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That increased resistance over constant voltage will decrease current.
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Verbally state V = IxR
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V = electromotive force (volts)
I = current (amperes) R = resistance (ohms) |
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what is the function of a circuit breaker?
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Fire prevention
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How does a circuit breaker work to prevent fire?
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The circuit interrupts the continuity of the circuit preventing a buildup of heat
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Electrical equipment involves what 3 wires?
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Receives power by the live wire
Power returns by the neutral wire and is grounded by the third wire |
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What happens when a person touches a "live" wire with out a "ground wire"?
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Current will flow through the person’s body to the ground the body is now part of the completed circuit.
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The grounding wire is a lower/higher resistance wire than a human body?
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Lower resistance
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A macro shock can result in the following injuries as the current passes through the body
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Burns
Fatal injuries Tingling, pain, muscle contraction dysrythmias ventricular fib |
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What current macroshock could result in dysrythmias ventricular fib?
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current is 100-300 mA
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Macro shocks are caused by a
(not a current specific answer) |
Current large enough to cause injury to the body’s surface
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What effect could a macroshock have on a patient with a preexisting cardiac disease?
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Earlier ectopy
Fibrillation |
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What is the body's natural impedance to electricity?
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dry, intact skin
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Why do ECG need gel?
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for the current to pass through with less resistance?
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Why do burns occur as a result of macro shock?
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the heat generated by the current impeded by skin
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Impedance is
greatest with skin less with skin least with a conduit skin |
dry
damp through |
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How many mA can stop the heart?
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0.1 mA
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Under what conditions is 0.1 mA sufficient to stop the heart?
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if the current bypasses the skin and conducted within the body
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Tingeling of the skin is caused by what mA?
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0.1 mA
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Name 3 ways that current can flow to the heart?
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CVP line
PA line esophageal stethascope |
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A ground fault circuit interrupter interrupts the circuit upon detecting how may amperes?
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5 mA
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A ground fault circuit interrupter monitors the amperes traveling what wires?
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going out the live wire
returning by the neutral wire able to detect an unequal leak at 5 mA |
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Ground fault circuit interrupter
or Isolated power systems are preferred in the operating room? |
Isolated power systems
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Integrity of the Isolated power system is assessed by what monitor?
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Line Isolation montior
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When does the Line Isolation monitor in the Isolated power system alarm?
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when leaks of 2-5 mA flow to groud
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Will monitors continue to work when the isolation monitor alarms
for 2-5 mA short circuit? |
Yes
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What should be done by the CRNA if the isolation monitor alarms for greater than 5 mA?
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monitors will still work
devices should be disconnected in order beginning with the last one plugged in. |
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What does resistance to flow cause?
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Heat
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Heat energy is used to cut or coagulate tissue at what high frequencies?
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400 kHz to 1 MHz
this frequency does not usually cause neuromuscular stimulation |
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What relationship occurs between current density (flow per unit area) to heating effect?
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direct relationship
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Is the patient grounded during electrosugury?
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No
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Where is the current actually traveling during electrosurgury?
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though the patient
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Why is the patient not burned by current travel during electrosurgury?
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the disbursive electrode pad is a large surface area so burns do not occur as the current returns to the ESU
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Bipolar describes what surgical instrument?
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a cautery tool forcept like device that prevents widespread tissue coagulation
consists of two tongs |
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Why does a bipolar cautery forcept tool not require a grounding pad?
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The current enters one prong and exits through the other
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Name hazards of electrosurgery.
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Electrocution
Fire Burns Interference with other electronic equipment |
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a properly funcitoning ESU is unlikely to electrocute but name another hazard.
(feet) |
accidentally stepping on foot petal would activate the tip and act as an ignition source
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If the disbursive pad is secured over a smaller arean what may occur?
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current may exit through a smaller are and may cause a burn
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Where would the current exit if the pad is unattached?
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The ESU will not work at all
(rings ecg leads pulse ox probe metal ring on patient finger) |
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What should a patient not wear in the operating room?
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any metal studs rings
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What is recommended done to an ICD during electrosurgery?
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recommended to deactivate ICD
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Newer models of pacemakers are shielded from what?
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current from electrosurgical tools
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Name safety measures that should be taken with the dispersion plate used during electrosurgery.
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Not with heart between knife and plate
Keep bovie cables away from pacer leads Ensure pad is attached securely Limit O2, N2O, flammable prep agents (especially head and neck surgery) |
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Name 2 types of radiation
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Electromagnetic radiation
Particulate radiation |
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what is the range of electromagnetic radiation?
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from visible light, radio frequency to x and gamma radiaiton
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Name 3 Radiation procedures
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Radiography
Fluoroscopy Brachytherapy (Encapsulated gamma-emitting radiation placed into patient) |
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Where must radiation monitoring devices be worn?
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outside of any shielding apparel
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ALARA
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judicious use of ionizing radiation
awareness of risks |
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What are 3 radiation exposures factors
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time
distance sheilding |
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At what distance will the receiver get 1/4 of the original energy?
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double the distance
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What are three ingreedients of a fire?
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gas
source of ignition flammable substance |
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Where can a gas rich environment occur in the OR with a MAC patient?
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under the drapes from trapping of nasal canula air
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Name sources of ignition in the operating room
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Electrosurgical cautery unit
Hot wire cautery tip Lasers OR lights Heated probes Camera scopes Defective electrical equipment Static electricity |
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Name combustable material in the operating room
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Everything!
ETT Tape Oxygen cannula Sponges Lubricants, ointments, cleaning and prep solutions Drapes Covers Mattresses Gowns Throat packs Gloves Nasogastric tubes Masks Paper products Tourniquets Blood pressure cuffs |
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What is the goal of fire safety in the OR?
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eliminate danger to the patients AND the staff
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What does a CRNA do during a ETT fire?
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Remove and/or extinguish burning material on or in patient
If fire is under and in water-repellant drape, water and extinguishing materials poured onto it are ineffective Pull burning materials off of patient Disconnect power supply before trying to extinguish with water or dry chemical |
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What is your top priority for CRNA's in an ETT fire?
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get the fire off of the patient (put out)
take ETT out mask ventilate possibly retube expect a bronchoscopy |
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Before you put out a fire on an ETT patient (with dry chemical or saline)
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unplug electrical equipment
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