, TABLE OF CONTENTS
Part 1: Gases and Ventilation
Chapter 1: Medical Gases: Storage and Supply
Chapter 2: The Anesthesia Machine and Workstation
Chapter 3: Anesthesia Vaporizers
Chapter 4: Breathing Circuits
Chapter 5: Waste Anesthetic Gases and Scavenging Systems
Chapter 6: Anesthesia Ventilators
Chapter 7: Humidification and Filtration
Part 2: System Monitors
Chapter 8: Respiratory Gas Monitoring
Chapter 9: Monitoring Ventilation
Part 3: Patient Monitors
Chapter 10: Capnography
Chapter 11: Pulse Oximetry
Chapter 12: Hemodynamic Monitoring
Chapter 13: Temperature Monitoring
Part 4: Other Equipment
Chapter 14: Airway Equipment
Chapter 15: Preventing Transmission of Infectious Diseases
Chapter 16: Infusion Pumps
Part 5: Vigilance, Alarms, and Ergonomics
Chapter 17: Vigilance, Alarms, and Integrated Monitoring Systems
Chapter 18: Ergonomics of the Anesthesia Workspace
Part 6: Special Conditions
Chapter 19: Closed-Circuit Anesthesia
Chapter 20: Anesthesia Delivery in the MRI Environment
Chapter 21: Anesthesia at High Altitude
Chapter 22: Anesthesia in Difficult Locations and in Developing Countries
Part 7: Safety, Standards, and Quality
Chapter 23: Hazards of the Anesthesia Delivery System
Chapter 24: Electrical and Fire Safety
Chapter 25: Machine Checkout and Quality Assurance
Chapter 26: Risk Management and Medicolegal Aspects of Anesthesia Equipment Use
Chapter 27: Standards and Regulatory Considerations
, Part 1: Gases and Ventilation
Chapter 1: Medical Gases: Storage and Supply
1. Which physical property explains why an oxygen E-cylinder pressure gauge decreases proportionally with
gas consumption, while a nitrous oxide gauge remains constant until the liquid phase is depleted?
A. Oxygen exists solely as a compressed gas because its critical temperature is below room temperature.
B. Oxygen possesses a higher molecular weight than nitrous oxide, preventing liquefaction under pressure.
C. Oxygen undergoes adiabatic expansion within the cylinder that continuously regenerates internal gas
pressure.
D. Oxygen dissolves rapidly into cylinder wall metal alloys while nitrous oxide remains suspended in vapor.
Answer: A
Rationale: Oxygen has a critical temperature of -119°C, which is well below room temperature, meaning it cannot be
liquefied by pressure alone at ambient temperatures and exists entirely as a gas where pressure correlates linearly with
volume. In contrast, nitrous oxide has a critical temperature of +36.5°C, allowing it to exist as a liquid in equilibrium with
vapor at 745 psig until the liquid phase is exhausted.
Keywords: [critical temperature, compressed gases, cylinder physics]
2. An oxygen E-cylinder on an anesthesia machine registers a pressure of 1000 psig. Assuming a standard full
cylinder contains 660 L at 2000 psig, approximately how many liters of oxygen remain?
A. Approximately 150 liters of oxygen remain in the cylinder.
B. Approximately 450 liters of oxygen remain in the cylinder.
C. Approximately 330 liters of oxygen remain in the cylinder.
D. Approximately 220 liters of oxygen remain in the cylinder.
Answer: C
Rationale: Because oxygen follows Boyle's law and exists as a compressed gas above its critical temperature, pressure
,is directly proportional to remaining volume. At 1000 psig, exactly half of the full 2000 psig pressure remains,
corresponding to half of the 660 L capacity, or approximately 330 L.
Keywords: [oxygen volume, E-cylinder calculation, Boyle's law]
3. At what remaining volume in a standard nitrous oxide E-cylinder does the liquid phase become completely
exhausted, causing the pressure gauge to drop below 745 psig?
A. When approximately 800 liters of nitrous oxide gas remain in the cylinder.
B. When approximately 400 liters of nitrous oxide gas remain in the cylinder.
C. When approximately 150 liters of nitrous oxide gas remain in the cylinder.
D. When approximately 600 liters of nitrous oxide gas remain in the cylinder.
Answer: B
Rationale: A full nitrous oxide E-cylinder contains 1590 L of gas in liquid-vapor equilibrium at 745 psig. The pressure
remains constant at 745 psig until all liquid vaporizes, which occurs when approximately 400 L (about 25% of total
capacity) remains, after which pressure declines rapidly with use.
Keywords: [nitrous oxide, liquid exhaustion, cylinder pressure]
4. Which pin configuration in the Pin Index Safety System (PISS) is designated specifically for medical oxygen
cylinders?
A. Pins located at positions 2 and 6.
B. Pins located at positions 1 and 5.
C. Pins located at positions 3 and 5.
D. Pins located at positions 2 and 5.
Answer: D
Rationale: The Pin Index Safety System uses specific pin pairings to prevent accidental connection of an incorrect gas
cylinder to a machine yoke. Oxygen is assigned pin positions 2 and 5, nitrous oxide uses positions 3 and 5, and medical
air uses positions 1 and 5.
Keywords: [PISS, oxygen pin index, safety systems]
5. Which pin configuration in the Pin Index Safety System (PISS) is designated specifically for medical air
cylinders?
A. Pins located at positions 1 and 5.
, B. Pins located at positions 2 and 5.
C. Pins located at positions 1 and 6.
D. Pins located at positions 3 and 5.
Answer: A
Rationale: Medical air cylinders utilize pin positions 1 and 5 on the hanger yoke to prevent misconnection. In comparison,
oxygen uses 2 and 5, while nitrous oxide uses 3 and 5.
Keywords: [medical air, PISS, pin index]
6. What is the primary function of the Diameter Index Safety System (DISS) on modern anesthesia
workstations?
A. Vent excessive circuit pressure into the scavenging system to prevent barotrauma.
B. Prevent accidental cross-connection of pipeline gas supply hoses to incorrect machine inlets.
C. Regulate intermediate pipeline pressure down to low-pressure flowmeter operational ranges.
D. Automatically shut off nitrous oxide delivery whenever oxygen supply pressure falls.
Answer: B
Rationale: The Diameter Index Safety System provides non-interchangeable threaded connections with unique bore and
thread diameters for each medical gas. This mechanical safeguard prevents attaching an oxygen hose to a nitrous oxide
inlet or vice versa at pipeline terminals.
Keywords: [DISS, pipeline safety, misconnection prevention]
7. What is the standard operating pressure range maintained in central hospital medical gas pipeline systems
in the United States?
A. 70 to 75 pounds per square inch gauge (psig).
B. 15 to 25 pounds per square inch gauge (psig).
C. 30 to 35 pounds per square inch gauge (psig).
D. 50 to 55 pounds per square inch gauge (psig).
Answer: D
Rationale: In the United States, central medical gas pipeline systems deliver oxygen, nitrous oxide, and medical air at a
standardized pressure of 50 to 55 psig (345 to 380 kPa). This standardized intermediate pressure powers pneumatic
ventilators, flush valves, and workstation flow controls.
Keywords: [pipeline pressure, operating standards, intermediate pressure]
,8. Why must oil, grease, or hydrocarbon lubricants never be applied to medical gas cylinder valves or
regulators?
A. Hydrocarbon lubricants corrode internal brass fittings, causing persistent microscopic gas leaks.
B. Lubricants clog downstream variable-orifice flowmeter tubes, leading to inaccurate volume readings.
C. Adiabatic compression of high-pressure gas generates extreme heat that can cause explosive ignition.
D. Chemical interactions between hydrocarbons and oxygen neutralize the pharmacological potency of the
gas.
Answer: C
Rationale: When a cylinder valve is opened rapidly, recompression of gas inside the regulator occurs adiabatically
without heat dissipation, generating temperatures exceeding 1000°C. In an oxygen-enriched atmosphere, this extreme
thermal surge causes spontaneous combustion and explosive ignition of flammable hydrocarbons.
Keywords: [adiabatic compression, fire hazard, cylinder handling]
9. In a hospital with a bulk liquid oxygen supply system, at what temperature range is the liquid oxygen
typically stored inside the insulated cryogenic vessel?
A. Between -20°C and -35°C under high pressure.
B. Between -160°C and -180°C under moderate pressure.
C. Between -220°C and -240°C under vacuum seal.
D. Between -50°C and -70°C under ambient pressure.
Answer: B
Rationale: Bulk liquid oxygen is stored as a cryogenic liquid in vacuum-insulated double-walled stainless steel containers
at temperatures between -160°C and -180°C (boiling point is -183°C at 1 atm). Vaporization coils convert the liquid to gas
at controlled pressures of approximately 250 psi before line regulation to 50-55 psi.
Keywords: [bulk liquid oxygen, cryogenic storage, pipeline supply]
10. How does an oxygen concentrator utilizing Pressure Swing Adsorption (PSA) technology extract oxygen
from ambient air?
A. Zeolite molecular sieves selectively adsorb nitrogen under pressure, leaving concentrated oxygen.
B. Semipermeable silicone membranes electrochemically hydrolyze water molecules into pure oxygen.
C. Cryogenic cooling coils condense oxygen into liquid while venting ambient nitrogen gas.
D. Catalytic combustion chambers burn atmospheric nitrogen, releasing unreacted medical-grade oxygen.
Answer: A
,Rationale: Pressure Swing Adsorption oxygen concentrators pass compressed ambient air through canisters packed with
synthetic zeolite mineral sieves. Under pressure, the zeolite crystalline structure adsorbs nitrogen molecules while
allowing oxygen and argon to pass through, yielding 90% to 95% oxygen.
Keywords: [oxygen concentrator, PSA technology, zeolite sieve]
11. Which alarm system provides immediate visual and audible warnings of medical gas pipeline pressure
deviations outside ±20% directly within specific surgical suites?
A. Master alarm panels located in the hospital engineering department.
B. Electronic hospital billing sensors tracking oxygen flow consumption.
C. Individual cylinder pressure gauges mounted on machine hanger yokes.
D. Area alarm panels located near operating room clusters.
Answer: D
Rationale: Area alarm panels are strategically placed in clinical areas such as surgical suites, intensive care units, and
recovery rooms to alert clinical personnel immediately if line pressure drops below ~40 psig or exceeds ~60 psig. In
contrast, master alarm panels monitor source supply systems in physical plant locations.
Keywords: [area alarms, pipeline monitoring, alarm systems]
12. Where are pipeline emergency zone shutoff valves located relative to the operating suites they control?
A. Immediately outside the surgical rooms on the corridor wall for rapid emergency access.
B. Inside the surgical sterile core next to the automated scrub sink supply plumbing.
C. Inside the central basement engineering maintenance room behind secure lock and key.
D. Directly behind the anesthesia machine housing adjacent to the electrical isolation transformer.
Answer: A
Rationale: Zone shutoff valves must be positioned immediately outside the entrance to operating rooms in main corridors
so that non-scrubbed personnel can rapidly isolate gas supplies during fires or major line breaches without entering the
affected operating suite.
Keywords: [zone valves, pipeline shutoff, fire safety]
13. What is the legal color-coding convention for medical nitrous oxide cylinders in the United States?
A. Green cylinder body and shoulder.
B. Gray cylinder body and shoulder.
, C. Blue cylinder body and shoulder.
D. Yellow cylinder body and shoulder.
Answer: C
Rationale: In the United States, medical gas cylinders follow Color Association standards: nitrous oxide is light blue,
oxygen is green (white internationally), medical air is yellow (black and white internationally), carbon dioxide is gray, and
nitrogen is black.
Keywords: [color-coding, nitrous oxide, cylinder identification]
14. What is the primary danger associated with an accidental medical gas pipeline crossover in a hospital?
A. Accumulation of toxic trace gases triggering malignant hyperthermia in susceptible individuals.
B. Delivery of an anoxic gas mixture through pipeline outlets labeled as medical oxygen.
C. Excessive line pressure causing explosive rupture of internal workstation flowmeter tubes.
D. Immediate electrical tripping of line isolation monitors from conductive gas moisture.
Answer: B
Rationale: Pipeline crossover accidents occur when piping systems are misconnected during construction or
maintenance, routing nitrous oxide or nitrogen into lines labeled for oxygen. When connected to the anesthesia
workstation, the machine delivers a lethal, hypoxic gas mixture through the oxygen flowmeter.
Keywords: [pipeline crossover, hypoxic gas, medical gas hazards]
15. During a suspected pipeline crossover where the oxygen analyzer indicates 0% FiO2 despite 100% dialed
oxygen, what is the mandatory immediate action?
A. Switch the machine master switch off and on to reboot the electronic proportioning system.
B. Engage the oxygen flush valve continuously to clear contaminated gas from the circuit.
C. Increase dialed oxygen flow to maximum while keeping the pipeline hose firmly connected.
D. Disconnect the pipeline oxygen hose and fully open the backup oxygen E-cylinder.
Answer: D
Rationale: If pipeline gas is contaminated, simply opening the backup oxygen cylinder is ineffective because pipeline
pressure (50-55 psig) exceeds cylinder first-stage regulated pressure (40-45 psig), causing the machine to preferential
consume pipeline gas. The pipeline hose must be physically disconnected so the machine switches to backup cylinder
oxygen.
Keywords: [pipeline crossover, emergency protocol, backup cylinder]
, 16. What pressure does the primary cylinder regulator reduce high cylinder pressure down to before entering
the workstation intermediate-pressure system?
A. Approximately 40 to 45 pounds per square inch gauge (psig).
B. Approximately 14 to 16 pounds per square inch gauge (psig).
C. Approximately 75 to 80 pounds per square inch gauge (psig).
D. Approximately 50 to 55 pounds per square inch gauge (psig).
Answer: A
Rationale: First-stage cylinder pressure regulators reduce variable cylinder pressures (up to 2200 psig for O2) down to
approximately 40 to 45 psig. Because this is lower than pipeline supply pressure (50-55 psig), the workstation
preferentially consumes pipeline gas when both sources are connected.
Keywords: [pressure regulator, first-stage regulator, cylinder supply]
17. Which component in the cylinder hanger yoke assembly prevents gas from transfilling into an adjacent
empty cylinder on a dual-cylinder manifold?
A. A spring-loaded pressure relief pop-off valve on the regulator.
B. A bimetallic temperature-compensating expansion element.
C. A one-way check valve situated within the yoke housing.
D. A fusible alloy safety plug fitted into the cylinder valve stem.
Answer: C
Rationale: Hanger yokes feature internal check valves that ensure unidirectional gas flow from the cylinder into the
machine. This prevents transfilling of gas from a full cylinder into an adjacent empty cylinder and prevents gas from
leaking into the room when a cylinder is removed.
Keywords: [hanger yoke, check valve, transfilling prevention]
18. What is the function of the fusible plug (Wood's metal) safety device incorporated into compressed gas
cylinder valves?
A. Ruptures when cylinder internal pressure exceeds five times normal working limits.
B. Melts at high temperatures (around 70°C to 100°C) to vent gas before cylinder wall rupture.
C. Absorbs combustible hydrocarbons to prevent adiabatic compression ignition.
D. Seals the cylinder valve automatically if excessive gas flow velocity is detected.
Answer: B
Part 1: Gases and Ventilation
Chapter 1: Medical Gases: Storage and Supply
Chapter 2: The Anesthesia Machine and Workstation
Chapter 3: Anesthesia Vaporizers
Chapter 4: Breathing Circuits
Chapter 5: Waste Anesthetic Gases and Scavenging Systems
Chapter 6: Anesthesia Ventilators
Chapter 7: Humidification and Filtration
Part 2: System Monitors
Chapter 8: Respiratory Gas Monitoring
Chapter 9: Monitoring Ventilation
Part 3: Patient Monitors
Chapter 10: Capnography
Chapter 11: Pulse Oximetry
Chapter 12: Hemodynamic Monitoring
Chapter 13: Temperature Monitoring
Part 4: Other Equipment
Chapter 14: Airway Equipment
Chapter 15: Preventing Transmission of Infectious Diseases
Chapter 16: Infusion Pumps
Part 5: Vigilance, Alarms, and Ergonomics
Chapter 17: Vigilance, Alarms, and Integrated Monitoring Systems
Chapter 18: Ergonomics of the Anesthesia Workspace
Part 6: Special Conditions
Chapter 19: Closed-Circuit Anesthesia
Chapter 20: Anesthesia Delivery in the MRI Environment
Chapter 21: Anesthesia at High Altitude
Chapter 22: Anesthesia in Difficult Locations and in Developing Countries
Part 7: Safety, Standards, and Quality
Chapter 23: Hazards of the Anesthesia Delivery System
Chapter 24: Electrical and Fire Safety
Chapter 25: Machine Checkout and Quality Assurance
Chapter 26: Risk Management and Medicolegal Aspects of Anesthesia Equipment Use
Chapter 27: Standards and Regulatory Considerations
, Part 1: Gases and Ventilation
Chapter 1: Medical Gases: Storage and Supply
1. Which physical property explains why an oxygen E-cylinder pressure gauge decreases proportionally with
gas consumption, while a nitrous oxide gauge remains constant until the liquid phase is depleted?
A. Oxygen exists solely as a compressed gas because its critical temperature is below room temperature.
B. Oxygen possesses a higher molecular weight than nitrous oxide, preventing liquefaction under pressure.
C. Oxygen undergoes adiabatic expansion within the cylinder that continuously regenerates internal gas
pressure.
D. Oxygen dissolves rapidly into cylinder wall metal alloys while nitrous oxide remains suspended in vapor.
Answer: A
Rationale: Oxygen has a critical temperature of -119°C, which is well below room temperature, meaning it cannot be
liquefied by pressure alone at ambient temperatures and exists entirely as a gas where pressure correlates linearly with
volume. In contrast, nitrous oxide has a critical temperature of +36.5°C, allowing it to exist as a liquid in equilibrium with
vapor at 745 psig until the liquid phase is exhausted.
Keywords: [critical temperature, compressed gases, cylinder physics]
2. An oxygen E-cylinder on an anesthesia machine registers a pressure of 1000 psig. Assuming a standard full
cylinder contains 660 L at 2000 psig, approximately how many liters of oxygen remain?
A. Approximately 150 liters of oxygen remain in the cylinder.
B. Approximately 450 liters of oxygen remain in the cylinder.
C. Approximately 330 liters of oxygen remain in the cylinder.
D. Approximately 220 liters of oxygen remain in the cylinder.
Answer: C
Rationale: Because oxygen follows Boyle's law and exists as a compressed gas above its critical temperature, pressure
,is directly proportional to remaining volume. At 1000 psig, exactly half of the full 2000 psig pressure remains,
corresponding to half of the 660 L capacity, or approximately 330 L.
Keywords: [oxygen volume, E-cylinder calculation, Boyle's law]
3. At what remaining volume in a standard nitrous oxide E-cylinder does the liquid phase become completely
exhausted, causing the pressure gauge to drop below 745 psig?
A. When approximately 800 liters of nitrous oxide gas remain in the cylinder.
B. When approximately 400 liters of nitrous oxide gas remain in the cylinder.
C. When approximately 150 liters of nitrous oxide gas remain in the cylinder.
D. When approximately 600 liters of nitrous oxide gas remain in the cylinder.
Answer: B
Rationale: A full nitrous oxide E-cylinder contains 1590 L of gas in liquid-vapor equilibrium at 745 psig. The pressure
remains constant at 745 psig until all liquid vaporizes, which occurs when approximately 400 L (about 25% of total
capacity) remains, after which pressure declines rapidly with use.
Keywords: [nitrous oxide, liquid exhaustion, cylinder pressure]
4. Which pin configuration in the Pin Index Safety System (PISS) is designated specifically for medical oxygen
cylinders?
A. Pins located at positions 2 and 6.
B. Pins located at positions 1 and 5.
C. Pins located at positions 3 and 5.
D. Pins located at positions 2 and 5.
Answer: D
Rationale: The Pin Index Safety System uses specific pin pairings to prevent accidental connection of an incorrect gas
cylinder to a machine yoke. Oxygen is assigned pin positions 2 and 5, nitrous oxide uses positions 3 and 5, and medical
air uses positions 1 and 5.
Keywords: [PISS, oxygen pin index, safety systems]
5. Which pin configuration in the Pin Index Safety System (PISS) is designated specifically for medical air
cylinders?
A. Pins located at positions 1 and 5.
, B. Pins located at positions 2 and 5.
C. Pins located at positions 1 and 6.
D. Pins located at positions 3 and 5.
Answer: A
Rationale: Medical air cylinders utilize pin positions 1 and 5 on the hanger yoke to prevent misconnection. In comparison,
oxygen uses 2 and 5, while nitrous oxide uses 3 and 5.
Keywords: [medical air, PISS, pin index]
6. What is the primary function of the Diameter Index Safety System (DISS) on modern anesthesia
workstations?
A. Vent excessive circuit pressure into the scavenging system to prevent barotrauma.
B. Prevent accidental cross-connection of pipeline gas supply hoses to incorrect machine inlets.
C. Regulate intermediate pipeline pressure down to low-pressure flowmeter operational ranges.
D. Automatically shut off nitrous oxide delivery whenever oxygen supply pressure falls.
Answer: B
Rationale: The Diameter Index Safety System provides non-interchangeable threaded connections with unique bore and
thread diameters for each medical gas. This mechanical safeguard prevents attaching an oxygen hose to a nitrous oxide
inlet or vice versa at pipeline terminals.
Keywords: [DISS, pipeline safety, misconnection prevention]
7. What is the standard operating pressure range maintained in central hospital medical gas pipeline systems
in the United States?
A. 70 to 75 pounds per square inch gauge (psig).
B. 15 to 25 pounds per square inch gauge (psig).
C. 30 to 35 pounds per square inch gauge (psig).
D. 50 to 55 pounds per square inch gauge (psig).
Answer: D
Rationale: In the United States, central medical gas pipeline systems deliver oxygen, nitrous oxide, and medical air at a
standardized pressure of 50 to 55 psig (345 to 380 kPa). This standardized intermediate pressure powers pneumatic
ventilators, flush valves, and workstation flow controls.
Keywords: [pipeline pressure, operating standards, intermediate pressure]
,8. Why must oil, grease, or hydrocarbon lubricants never be applied to medical gas cylinder valves or
regulators?
A. Hydrocarbon lubricants corrode internal brass fittings, causing persistent microscopic gas leaks.
B. Lubricants clog downstream variable-orifice flowmeter tubes, leading to inaccurate volume readings.
C. Adiabatic compression of high-pressure gas generates extreme heat that can cause explosive ignition.
D. Chemical interactions between hydrocarbons and oxygen neutralize the pharmacological potency of the
gas.
Answer: C
Rationale: When a cylinder valve is opened rapidly, recompression of gas inside the regulator occurs adiabatically
without heat dissipation, generating temperatures exceeding 1000°C. In an oxygen-enriched atmosphere, this extreme
thermal surge causes spontaneous combustion and explosive ignition of flammable hydrocarbons.
Keywords: [adiabatic compression, fire hazard, cylinder handling]
9. In a hospital with a bulk liquid oxygen supply system, at what temperature range is the liquid oxygen
typically stored inside the insulated cryogenic vessel?
A. Between -20°C and -35°C under high pressure.
B. Between -160°C and -180°C under moderate pressure.
C. Between -220°C and -240°C under vacuum seal.
D. Between -50°C and -70°C under ambient pressure.
Answer: B
Rationale: Bulk liquid oxygen is stored as a cryogenic liquid in vacuum-insulated double-walled stainless steel containers
at temperatures between -160°C and -180°C (boiling point is -183°C at 1 atm). Vaporization coils convert the liquid to gas
at controlled pressures of approximately 250 psi before line regulation to 50-55 psi.
Keywords: [bulk liquid oxygen, cryogenic storage, pipeline supply]
10. How does an oxygen concentrator utilizing Pressure Swing Adsorption (PSA) technology extract oxygen
from ambient air?
A. Zeolite molecular sieves selectively adsorb nitrogen under pressure, leaving concentrated oxygen.
B. Semipermeable silicone membranes electrochemically hydrolyze water molecules into pure oxygen.
C. Cryogenic cooling coils condense oxygen into liquid while venting ambient nitrogen gas.
D. Catalytic combustion chambers burn atmospheric nitrogen, releasing unreacted medical-grade oxygen.
Answer: A
,Rationale: Pressure Swing Adsorption oxygen concentrators pass compressed ambient air through canisters packed with
synthetic zeolite mineral sieves. Under pressure, the zeolite crystalline structure adsorbs nitrogen molecules while
allowing oxygen and argon to pass through, yielding 90% to 95% oxygen.
Keywords: [oxygen concentrator, PSA technology, zeolite sieve]
11. Which alarm system provides immediate visual and audible warnings of medical gas pipeline pressure
deviations outside ±20% directly within specific surgical suites?
A. Master alarm panels located in the hospital engineering department.
B. Electronic hospital billing sensors tracking oxygen flow consumption.
C. Individual cylinder pressure gauges mounted on machine hanger yokes.
D. Area alarm panels located near operating room clusters.
Answer: D
Rationale: Area alarm panels are strategically placed in clinical areas such as surgical suites, intensive care units, and
recovery rooms to alert clinical personnel immediately if line pressure drops below ~40 psig or exceeds ~60 psig. In
contrast, master alarm panels monitor source supply systems in physical plant locations.
Keywords: [area alarms, pipeline monitoring, alarm systems]
12. Where are pipeline emergency zone shutoff valves located relative to the operating suites they control?
A. Immediately outside the surgical rooms on the corridor wall for rapid emergency access.
B. Inside the surgical sterile core next to the automated scrub sink supply plumbing.
C. Inside the central basement engineering maintenance room behind secure lock and key.
D. Directly behind the anesthesia machine housing adjacent to the electrical isolation transformer.
Answer: A
Rationale: Zone shutoff valves must be positioned immediately outside the entrance to operating rooms in main corridors
so that non-scrubbed personnel can rapidly isolate gas supplies during fires or major line breaches without entering the
affected operating suite.
Keywords: [zone valves, pipeline shutoff, fire safety]
13. What is the legal color-coding convention for medical nitrous oxide cylinders in the United States?
A. Green cylinder body and shoulder.
B. Gray cylinder body and shoulder.
, C. Blue cylinder body and shoulder.
D. Yellow cylinder body and shoulder.
Answer: C
Rationale: In the United States, medical gas cylinders follow Color Association standards: nitrous oxide is light blue,
oxygen is green (white internationally), medical air is yellow (black and white internationally), carbon dioxide is gray, and
nitrogen is black.
Keywords: [color-coding, nitrous oxide, cylinder identification]
14. What is the primary danger associated with an accidental medical gas pipeline crossover in a hospital?
A. Accumulation of toxic trace gases triggering malignant hyperthermia in susceptible individuals.
B. Delivery of an anoxic gas mixture through pipeline outlets labeled as medical oxygen.
C. Excessive line pressure causing explosive rupture of internal workstation flowmeter tubes.
D. Immediate electrical tripping of line isolation monitors from conductive gas moisture.
Answer: B
Rationale: Pipeline crossover accidents occur when piping systems are misconnected during construction or
maintenance, routing nitrous oxide or nitrogen into lines labeled for oxygen. When connected to the anesthesia
workstation, the machine delivers a lethal, hypoxic gas mixture through the oxygen flowmeter.
Keywords: [pipeline crossover, hypoxic gas, medical gas hazards]
15. During a suspected pipeline crossover where the oxygen analyzer indicates 0% FiO2 despite 100% dialed
oxygen, what is the mandatory immediate action?
A. Switch the machine master switch off and on to reboot the electronic proportioning system.
B. Engage the oxygen flush valve continuously to clear contaminated gas from the circuit.
C. Increase dialed oxygen flow to maximum while keeping the pipeline hose firmly connected.
D. Disconnect the pipeline oxygen hose and fully open the backup oxygen E-cylinder.
Answer: D
Rationale: If pipeline gas is contaminated, simply opening the backup oxygen cylinder is ineffective because pipeline
pressure (50-55 psig) exceeds cylinder first-stage regulated pressure (40-45 psig), causing the machine to preferential
consume pipeline gas. The pipeline hose must be physically disconnected so the machine switches to backup cylinder
oxygen.
Keywords: [pipeline crossover, emergency protocol, backup cylinder]
, 16. What pressure does the primary cylinder regulator reduce high cylinder pressure down to before entering
the workstation intermediate-pressure system?
A. Approximately 40 to 45 pounds per square inch gauge (psig).
B. Approximately 14 to 16 pounds per square inch gauge (psig).
C. Approximately 75 to 80 pounds per square inch gauge (psig).
D. Approximately 50 to 55 pounds per square inch gauge (psig).
Answer: A
Rationale: First-stage cylinder pressure regulators reduce variable cylinder pressures (up to 2200 psig for O2) down to
approximately 40 to 45 psig. Because this is lower than pipeline supply pressure (50-55 psig), the workstation
preferentially consumes pipeline gas when both sources are connected.
Keywords: [pressure regulator, first-stage regulator, cylinder supply]
17. Which component in the cylinder hanger yoke assembly prevents gas from transfilling into an adjacent
empty cylinder on a dual-cylinder manifold?
A. A spring-loaded pressure relief pop-off valve on the regulator.
B. A bimetallic temperature-compensating expansion element.
C. A one-way check valve situated within the yoke housing.
D. A fusible alloy safety plug fitted into the cylinder valve stem.
Answer: C
Rationale: Hanger yokes feature internal check valves that ensure unidirectional gas flow from the cylinder into the
machine. This prevents transfilling of gas from a full cylinder into an adjacent empty cylinder and prevents gas from
leaking into the room when a cylinder is removed.
Keywords: [hanger yoke, check valve, transfilling prevention]
18. What is the function of the fusible plug (Wood's metal) safety device incorporated into compressed gas
cylinder valves?
A. Ruptures when cylinder internal pressure exceeds five times normal working limits.
B. Melts at high temperatures (around 70°C to 100°C) to vent gas before cylinder wall rupture.
C. Absorbs combustible hydrocarbons to prevent adiabatic compression ignition.
D. Seals the cylinder valve automatically if excessive gas flow velocity is detected.
Answer: B
