Electrical Safety & Radiology in Healthcare Settings Quiz
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Questions and Answers

What type of patient is susceptible to microshock?

  • Patients with an external conduit in direct contact with the heart (correct)
  • Patients with diabetes
  • Patients with severe allergies
  • Patients with asthma

    • What is the recommended maximum leakage current for microshock?

  • 20 mA
  • 10 µA (correct)
  • 5 mA
  • 1 A

    • What effect does a current of 50 mA have?

  • Pain & possible mechanical injury (correct)
  • Minimum perceptible
  • 'Let go' current before sustained muscle contraction
  • Maximum 'harmless' current

    • How does an isolation transformer work to provide power?

    <p>It uses electromagnetic induction to induce current in the ungrounded winding from the primary winding</p> Signup and view all the answers

    What is the purpose of a Line Isolation Monitor (LIM)?

    <p>To detect whether electrical systems are isolated from ground</p> Signup and view all the answers

    How does a Ground-Fault Circuit Interrupter (GFCI) provide shock protection?

    <p>By shutting off power before a second fault occurs</p> Signup and view all the answers

    What happens when a hot wire short circuits in a Line Isolation Monitor system?

    <p>'Harmless' current flows through the system</p> Signup and view all the answers

    What is the effect of a current of 100-300 mA?

    <p>Ventricular fibrillation (Vfib)</p> Signup and view all the answers

    What is the benefit of a Ground-Fault Circuit Interrupter (GFCI) over a Line Isolation Monitor (LIM)?

    <p>It provides immediate power shutoff before a second fault occurs</p> Signup and view all the answers

    What action should be taken when a Line Isolation Monitor (LIM) alarms?

    <p>Unplug each device in the reverse order of when it was plugged in</p> Signup and view all the answers

    What is the recommended distance to keep certain devices, such as cell phones and pacemakers, away from during surgery to avoid electromagnetic interference?

    <p>At least 6 inches away</p> Signup and view all the answers

    In the context of environmental hazards in the operating room, what is a recommended practice related to cords?

    <p>Keeping cords off the floor</p> Signup and view all the answers

    Which type of laser has very little tissue penetration and is commonly used for airway procedures like tumor debulking?

    <p>CO2 laser</p> Signup and view all the answers

    For fire risk management in the operating room, what should be done immediately if early warning signs like a pop, flash, or smoke are noticed?

    <p>Stop the procedure and carry out assigned tasks</p> Signup and view all the answers

    What should be done if an airway fire occurs during surgery?

    <p>Remove burning materials and drapes</p> Signup and view all the answers

    What is a high-risk situation that requires specific training and preparedness in the context of operating room fires?

    <p>Use of high-flow oxygen in MAC cases</p> Signup and view all the answers

    How can one manage an airway fire if it occurs during surgery?

    <p>Remove ETT, turn off gases, disconnect circuit</p> Signup and view all the answers

    What type of laser is known for being absorbed by hemoglobin and used primarily in eye and dermatological procedures?

    <p>$\text{Argon laser}$</p> Signup and view all the answers

    What is the formula for power in an electrical circuit according to Ohm's Law?

    <p>P = (I x R) x I</p> Signup and view all the answers

    In which situation does alternating current (AC) permit current flow even when the circuit is not complete?

    <p>When capacitance is low</p> Signup and view all the answers

    What is the primary factor that determines the severity of an electrical shock on a person?

    <p>Magnitude of the shock</p> Signup and view all the answers

    Which component in an electrical circuit is responsible for returning current back to the power source?

    <p>Neutral wire</p> Signup and view all the answers

    When does a short circuit occur in an electrical system?

    <p>When there is a zero-impedance load</p> Signup and view all the answers

    What is the primary difference between direct current (DC) and alternating current (AC)?

    <p>The direction of electron flow</p> Signup and view all the answers

    In an AC circuit, what happens to impedance as the frequency increases?

    <p>Impedance increases</p> Signup and view all the answers

    What does a conductor do in an electrical system?

    <p>Permits the flow of electrons</p> Signup and view all the answers

    Which substance opposes electron flow in an electrical system?

    <p>Insulator</p> Signup and view all the answers

    What is a characteristic of equipment with double insulation?

    <p>It can have 2 layers of insulation and a plastic exterior</p> Signup and view all the answers

    Why is microshock especially dangerous?

    <p>It creates a direct path to the heart</p> Signup and view all the answers

    What is the main function of intact ground wires in prevention?

    <p>They provide a low-resistance path for fault currents</p> Signup and view all the answers

    What happens if the equipment ground wires are broken?

    <p>The ESU will appear more dangerous than it actually is</p> Signup and view all the answers

    What is the frequency range of very high-frequency currents used in green dot electrosurgery units (ESU) - monopolar?

    <p>500,000 to 1 million Hz</p> Signup and view all the answers

    What is the main purpose of equipment ground wires in ESU units?

    <p>To reduce the risk of macroshock by providing a low-resistance path for fault currents</p> Signup and view all the answers

    Why is an intact ground wire essential in prevention?

    <p>It provides a safe path for fault currents to prevent macroshock</p> Signup and view all the answers

    What type of current does green dot electrosurgery units (ESU) - monopolar use?

    <p>Very high-frequency currents</p> Signup and view all the answers

    Why should energy return through an electrode to an electrosurgery unit (ESU) during use?

    <p>To ensure proper functioning and safety of the unit</p> Signup and view all the answers

    What is a primary reason for ensuring intact ground wires in medical equipment?

    <p>To provide a safe pathway for fault currents and prevent shocks</p> Signup and view all the answers

    Why is microshock particularly dangerous?

    <p>It can lead to a large density of current at the heart</p> Signup and view all the answers

    What is the primary role of intact ground wires in preventing electrical accidents?

    <p>To provide a low-resistance path for fault currents</p> Signup and view all the answers

    What is the key function of a Line Isolation Monitor (LIM) during surgery?

    <p>To detect ungrounded systems</p> Signup and view all the answers

    Why is the equipment return path through an electrode essential in electrosurgery units?

    <p>To ensure energy is dissipated evenly</p> Signup and view all the answers

    What is the significance of having two layers of insulation in equipment?

    <p>To minimize stray capacitance effects</p> Signup and view all the answers

    What is the purpose of a Line Isolation Monitor (LIM) in an electrical system?

    <p>To provide protection against electrical shock by turning a grounded system into a protected system.</p> Signup and view all the answers

    What effect does a current of 10 µA have on an individual susceptible to microshock?

    <p>Ventricular fibrillation (Vfib)</p> Signup and view all the answers

    Why do Ground-Fault Circuit Interrupters (GFCI) provide better shock protection than Line Isolation Monitors (LIM)?

    <p>They monitor both sides of the circuit for equality of flow.</p> Signup and view all the answers

    What is the primary function of an isolation transformer in an electrical system?

    <p>To isolate power from ground and prevent shocks.</p> Signup and view all the answers

    What happens when a neutral wire becomes grounded in an electrical system with a Line Isolation Monitor (LIM)?

    <p>There is no longer isolation from the ground but should not deliver a shock.</p> Signup and view all the answers

    What is the primary characteristic of a bipolar electrosurgery unit (ESU) compared to a monopolar ESU?

    <p>It doesn't need a dispersive electrode</p> Signup and view all the answers

    What is the formula to calculate power in an electrical circuit according to Ohm's Law?

    <p>P = (I x R) x I</p> Signup and view all the answers

    In terms of impedance in AC circuits, what happens as the frequency increases?

    <p>Impedance falls</p> Signup and view all the answers

    In the context of environmental hazards in the operating room, what is the recommended practice regarding cords?

    <p>Ensure they are off the floor and away from ceiling/wall plugs</p> Signup and view all the answers

    Why does a short circuit occur in an electrical system?

    <p>Zero-impedance load</p> Signup and view all the answers

    What is the best course of action in managing a fire on the patient during surgery?

    <p>Remove drapes and burning material, then assess patient's status</p> Signup and view all the answers

    What is the primary determining factor for the severity of an electrical shock on an individual?

    <p>Duration of current flow</p> Signup and view all the answers

    What is a key factor to consider in selecting appropriate protective measures against airway fires during surgery?

    <p>Applying saline to gauzes near the airway</p> Signup and view all the answers

    Which unit is used to measure the decay of a radioactive substance in one second?

    <p>Becquerel (Bq)</p> Signup and view all the answers

    What characteristic defines a conductor in an electrical system?

    <p>Substance that permits the flow of electrons</p> Signup and view all the answers

    What is the unit used to measure occupational radiation exposure?

    <p>Radiation equivalent man (Rem)</p> Signup and view all the answers

    Which body tissues are considered the most sensitive to biological effects of radiation exposure?

    <p>Fetus, bone marrow, intestinal lining, reproductive tissue</p> Signup and view all the answers

    In an X-ray, which view is most common where the X-rays pass from back to front of the chest?

    <p>Posterior Anterior</p> Signup and view all the answers

    What should be done immediately upon noticing early warning signs like a pop, flash, or smoke in managing fire risk in the operating room?

    <p>Stop the procedure and evacuate the room</p> Signup and view all the answers

    Which body part would scatter the most radiation when pictured on an X-ray due to its density?

    <p>Fetus</p> Signup and view all the answers

    What unit is used to measure occupational radiation exposure?

    <p>Radiation equivalent man (Rem)</p> Signup and view all the answers

    Which unit measures the decay of a radioactive substance in one second?

    <p>Becquerel (Bq)</p> Signup and view all the answers

    Which part of the body will scatter more radiation when pictured on an Xray due to its density?

    <p>Intestinal lining</p> Signup and view all the answers

    Which tissue is the least sensitive to biological effects of radiation exposure?

    <p>Mature RBCs</p> Signup and view all the answers

    What's the maximum yearly allowable occupational radiation exposure in rem?

    <p>5 rem</p> Signup and view all the answers

    What determines the amount of radiation scatter on an X-ray?

    <p>Density of the pictured body part</p> Signup and view all the answers

    Which substance decays at the same rate as 1 gram of radium?

    <p>Curie (Ci)</p> Signup and view all the answers

    What unit represents the quantity of radiation an individual receives?

    <p>Radiation absorbed dose (Rad)</p> Signup and view all the answers

    Which unit is used to measure the occupational radiation exposure?

    <p>Radiation equivalent man (Rem)</p> Signup and view all the answers

    What quantity does the unit Roentgen (R) measure?

    <p>Intensity of X-ray machine</p> Signup and view all the answers

    Which body part is considered least sensitive to the biological effects of radiation exposure?

    <p>Mature bone</p> Signup and view all the answers

    What substance decays in one second, as represented by the unit Becquerel (Bq)?

    <p>Radioactive substance</p> Signup and view all the answers

    In an X-ray, which part of the body will scatter more radiation with a stronger beam due to its density?

    <p>Bone marrow</p> Signup and view all the answers

    What is used to measure the quantity of radiation an individual receives?

    <p>Radiation equivalent man (Rem)</p> Signup and view all the answers

    Which unit represents a radioactive substance that decays at the same rate as 1 gram of radium?

    <p>Curie (Ci)</p> Signup and view all the answers

    What is the highest yearly allowable occupational radiation exposure in rem?

    <p>5 rem</p> Signup and view all the answers

    What is the unit used to measure the decay in one second?

    <p>Becquerel (Bq)</p> Signup and view all the answers

    Which tissue is considered the most sensitive to biological effects of radiation exposure?

    <p>Fetus</p> Signup and view all the answers

    What is the primary unit used to measure radiation exposure in an individual?

    <p>Radiation equivalent man (Rem)</p> Signup and view all the answers

    In an X-ray, what body part is considered the least sensitive to the biological effects of radiation exposure?

    <p>Mature bone</p> Signup and view all the answers

    Which radioactive substance decays at the same rate as 1 gram of radium?

    <p>Curie (Ci)</p> Signup and view all the answers

    What is the unit that measures the intensity of an X-ray machine?

    <p>Roentgen (R)</p> Signup and view all the answers

    Which body part will scatter more radiation when pictured on an X-ray due to its density?

    <p>Bone</p> Signup and view all the answers

    Which unit measures the quantity of radiation an individual receives?

    <p>Roentgen (R)</p> Signup and view all the answers

    Which tissues are considered to be the most sensitive to biological effects of radiation exposure?

    <p>Fetus, bone marrow, intestinal lining, reproductive tissue</p> Signup and view all the answers

    What represents a radioactive substance decaying at the same rate as 1 gram of radium?

    <p>Curie (Ci)</p> Signup and view all the answers

    What is the primary risk for exposure to radiation in a healthcare setting like the cath lab or ERCP?

    <p>Fluoroscopy procedures</p> Signup and view all the answers

    What is the primary determining factor for the intensity of an Xray beam?

    <p>Patient’s weight &amp; habitus</p> Signup and view all the answers

    What is the inverse square law of radiation exposure related to?

    <p>Intensity = 1/Distance^2</p> Signup and view all the answers

    Study Notes

    Principles of Electricity

    • Ohm's Law: E = I x R, where E is electromagnetic force (volts), I is current (amperes), and R is resistance (ohms)
    • Power (P) is equal to E x I, measured in watts
    • Joule is the unit of electrical work done, equal to watt-seconds

    Direct and Alternating Currents

    • Conductor: a substance that permits the flow of electrons
    • Direct current: electrons flow in the same direction
    • Alternating current: electron flow reverses direction at a regular interval
    • Impedance (Z) is directly proportional to frequency x inductance and inversely proportional to frequency x capacitance
    • As AC current frequency increases, capacitance and inductance increase, and impedance falls

    Capacitance and Inductance

    • Capacitor: 2 parallel conductors separated by an insulator, stores charge
    • Capacitance: measure of substance's ability to store charge
    • DC: charged by voltage source (battery), momentary current flow
    • AC: capacitor permits current flow even when circuit not complete by resistance
    • Electrosurgical units: 0.5 to 2 million Hz, high-frequency causes decrease in impedance
    • Stray capacitance: not designed into system

    Electrical Shock Hazards

    • Electric shock occurs when person contacts source of electricity
    • Load: amount of current flowing through a given device
    • Pacemakers, defibrillators: can injure/death, takes 3x as much DC as AC to cause Vfib
    • Impedance: high impedance circuit allows small current to flow, low impedance circuit draws large current
    • Short circuit: occurs when there is a zero-impedance load with a very large current flow
    • SOURCE OF SHOCKS: must contact electrical circuit at 2 points, voltage source causes current to flow
    • Severity of shock determined by amount of current (amps) and duration of current flow

    Electrical OR Safety

    • OR is a wet location with a lot of electronic equipment and devices
    • Ground: physical electrical connection to the earth
    • OR electrical equipment is usually grounded
    • Varying amounts of shock with varying degrees of injury and damage
    • Electrical current: hot wire, neutral wire, and source of voltage to drive flow through impedance (equipment, patient, personnel)
    • Hot wire: high voltage, conducts electricity to equipment
    • Neutral wire: low voltage – ground wire that returns current back to power source, completing circuit
    • Touching hot wire can lead to shock

    Microshock and Macroshock

    • Microshock: very small amounts of current applied to myocardium, electrically susceptible patient
    • Macroshock: large amounts of current flowing through a person, which can cause harm or death

    Electrosurgery

    • Electrosurgery unit (ESU): very high-frequency currents (500,000 to 1 million Hz) that pass through tissue
    • Heat is created by resistance of tissue to current
    • Cut or coagulation, low tissue penetration, does not excite contractile cells
    • Energy should return through an electrode to ESU during use, interferes with everything!

    Isolated Power Source

    • Isolation transformer: uses electromagnetic induction to induce current in ungrounded or secondary winding of transformer
    • No direct connection between equipment and utility company
    • Power is isolated from ground – no hot, no neutral
    • Very high impedance

    Line Isolation Monitor (LIM)

    • Protects against electrocution by turning a normal "grounded system" into a protected system
    • Continually detects whether electrical system is isolated from ground
    • Audible and visual alarms, usually alarms 2-5 mA between neutral and ground leads
    • If hot wire short circuits, system no longer isolated but should not deliver shock – less safe
    • Neutral wire becomes grounded, then complete circuit exists for when device touched

    Ground Fault Circuit Interrupter (GFCI)

    • Monitors both sides of circuit for equality of flow
    • If difference of 5 mA, power shut off
    • Better shock protection than LIM – shuts off power before second fault
    • But will d/c power to any equipment immediately even if it interferes with patient safety
    • Reset GFI

    Fire Safety

    • Cords off floor, ceiling/wall plugs, no multioutlet extension poor strips on the floor
    • Modern monitoring cords isolate patient from power supply
    • Generator power
    • At least 90-100 fires/year, 5-10% associated with serious injury/death
    • Burns, toxicants (2 types: IN or ON the patient; or remote)
    • Preparation for prevention of or fire:
      • Train OR personnel in OR fire management
      • Fire drills – practice
      • Assure equipment is available and working
      • Determine if high-risk situation exists
      • Team decision-making for prevention
      • Each person is assigned a task
    • Fire prevention:
      • Allow skin preps to dry before draping (3 min)
      • Place surgical drapes to prevent oxidizer build-up
      • Communication to minimize oxidizer-rich environment near ignition source
      • Keep oxygen concentration as low as possible
      • Avoid nitrous
      • Moisten gauzes/sponges near ignition source
    • Fire management:
      • Look for early warning signs (pop, flash, smoke)
      • Stop procedure; each member immediately carries out assigned task
      • Airway fire: simultaneously remove ETT, turn off gases, disconnect circuit, pour saline into airway
      • Remove burning materials, mask ventilate patient, assess injury, consider bronchoscopy, reintubate
      • Fire on the patient: turn off gases, remove drapes and burning material, extinguish flames with water, saline, or fire extinguisher
      • Assess patient's status, devise care plan, assess for smoke inhalation
      • Failure to extinguish: use CO2 fire extinguisher
      • Activate fire alarm, consider evacuation of room, close door and don't reopen
      • Turn off medical gas supply to room
      • Preserve scene, notify hospital risk manager, follow local regulatory reporting requirements, treat fire as adverse event, conduct drills regularly### AICD and Electrosurgery
    • AICD (Automatic Implantable Cardioverter Defibrillator) needs a magnet to prevent VFib (Ventricular Fibrillation) caused by 50-60 Hz stray current during coagulation mode near the heart and conductor
    • Power supply must be isolated from the ground
    • Bipolar ESU (Electrosurgical Unit) passes power between two blades, generating less power than monopolar ESU, and does not require a dispersive electrode

    Environmental Hazards

    • Cords must be kept off the floor and ceiling/wall plugs should be used
    • Multi-outlet extension strips should be avoided on the floor
    • Modern monitoring cords isolate the patient from the power supply
    • Generator power should be used instead of wall power

    Electromagnetic Interference (EMI)

    • Cell phones, cordless phones, radios, and wireless internet can cause EMI
    • Pacemakers, monitoring devices, ventilators, and infusion pumps can be affected by EMI
    • Keep at least 6 inches away from potential sources of EMI

    Fire Safety

    • There are at least 90-100 fires per year in the operating room, with 5-10% associated with serious injury or death
    • Burns and toxicants are the two types of fires: on the patient or remote
    • Preparation for fire prevention includes training OR personnel, conducting fire drills, and ensuring equipment is available and working
    • Each person in the OR should be assigned a task to prevent fires

    Fire Prevention

    • Allow skin preps to dry before draping (3 minutes)
    • Place surgical drapes to prevent oxidizer build-up
    • Communicate to minimize oxidizer-rich environment near ignition source
    • Keep oxygen concentration as low as possible
    • Avoid nitrous oxide
    • Moisten gauzes/sponges near ignition source

    Fire Management

    • Look for early warning signs (pop, flash, smoke)
    • Stop the procedure and each member should carry out their assigned task
    • For airway fires:
      • Simultaneously remove ETT, turn off gases, and disconnect circuit
      • Pour saline into the airway
      • Remove burning materials and mask ventilate the patient
      • Assess injury and consider bronchoscopy and reintubation
    • For fires on the patient:
      • Turn off gases and remove drapes and burning material
      • Extinguish flames with water, saline, or fire extinguisher
      • Assess patient's status and devise a care plan
      • Assess for smoke inhalation

    Fire Risk Management

    • Preserve the scene and notify the hospital risk manager
    • Follow local regulatory reporting requirements
    • Treat fire as an adverse event
    • Conduct drills regularly

    Increased Risk Procedures

    • Head and neck, upper chest MAC cases with high flow oxygen
    • Uncuffed tubes in airway procedures
    • Laparoscopic laser procedures

    Laser

    • Laser stands for Light Amplification by Stimulated Emission of Radiation
    • Types of lasers:
      • Nd:YAG (neodymium-doped YAG) - most powerful medical laser, 2-6 mm
      • Argon - used for eye and dermatology, absorbed by hemoglobin, tissue penetration 0.5-2 mm
      • KTP (potassium titanyl phosphate) and YAG (frequency doubled yttrium aluminum garnet)
      • CO2 laser - very little tissue penetration, absorbed by water, used for tumor debulking and airway
      • Helium-neon (He-Ne) - intense red light used for aiming CO2 and Nd:YAG lasers

    Radiology

    • Roentgen (R) - unit of radiation exposure
    • X-ray machine intensity affects radiation exposure
    • Radiation absorbed dose (Rad) - quantity of radiation an individual receives
    • Radiation equivalent man (Rem) - unit of occupational radiation exposure, yearly max is 5 rem
    • Curie (Ci) - radioactive substance that decays at the same rate with 1 g radium
    • Becquerel (Bq) - decay in one second
    • X-rays are dependent on:
      • Patient's weight and habitus
      • Density of pictured body part
      • Orientation of pictured X-ray beam
    • More radiation will scatter with stronger beam (obesity, thick body part, unusual view)
    • Most sensitive tissues to biological effects:
      • Fetus
      • Bone marrow
      • Intestinal lining
      • Reproductive tissue
    • Least sensitive tissues:
      • Mature RBCs
      • Mature bone
      • Mature cartilage
    • Highest risk of exposure:
      • Off-site anesthesia
      • Cath lab/EP lab
      • IR/CT/ERCP
      • Radiation therapy
      • OR: IOC, cysto, pain management, endovascular aneurysms, ortho
    • Protection:
      • Distance
      • Duration
      • Shielding
      • Inverse square law of radiation exposure (Intensity = 1/Distance^2)

    Normal X-ray

    • Density:
      • Air (darkest)
      • Fat
      • Water
      • Bone
      • Metal (lightest)
    • ABCDEFGHI - assessment of quality and airway
    • Quality - Position, Inspiration, exposure, rotation (PIER)
    • Posterior Anterior - most common view, X-rays pass from back to front of chest
    • Anterior Posterior - front to back X-ray, used a lot in ICU/OR due to immobility/supine position
    • Lateral Inspiration - lung cloudy/bigger heart on expiration, look for right-sided heart failure

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    Description

    Test your knowledge on electrical safety practices in healthcare settings, including concepts such as double insulation, microshock risks, and prevention measures like intact ground wires. Learn about the dangers of stray capacitance and radiofrequency from electrosurgical units.

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