Deck 40: Storage and Delivery of Medical Gases

Question 1

Large hospital air compressor systems must be capable of maintaining 50 pounds per square inch gauge (psig) at what flows?

A) 10 L/min
B) 15 L/min
C) 50 L/min
D) 100 L/min

Answer 1

D
Explanation: Large medical air compressors must provide high flow (at least 100 L/min) at the standard working pressure of 50 psig for all equipment in use.

Question 2

Which of the following methods of producing O₂ is commonly used in the home care setting?

A) Chemical decomposition
B) Electrolysis
C) Fractional distillation
D) Physical separation

Answer 2

D
Explanation: These devices, called O₂ concentrators, are used primarily for supplying low-flow O₂ in the home care setting.

Question 3

Which of the following equipment(s) could be powered by a small diaphragm or turbine air compressor?
1) Small-volume medication nebulizer
2) All-purpose large-volume jet nebulizer
3) Intermittent positive-pressure breathing device

A)1 only
B)1 and 2 only
C)2 and 3 only
D)1, 2, and 3

Answer 3

A

Question 4

Components of a large medical air compressor include which of the following?
1) Drying system
2) Diaphragm or turbine
3) Reservoir tank
4) Pressure-reducing valve

A)2 and 3 only
B)2 and 4 only
C)1, 2, and 3 only
D)1, 3, and 4 only

Question 5

Compressed gas cylinders are manufactured from which of the following?

A) Copper
B) Seamless steel
C) Seamless brass
D) Fiberglass

Question 6

What is the U.S. Food and Drug Administration (FDA) purity standard for O₂?

A) 21%
B) 90%
C) 95%
D) 99%

Question 7

Air for medical use in a hospital should be which of the following?
1) Particle-free
2) Oil-free
3) Dry

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Question 8

During inspection of the shoulder of a compressed gas cylinder, you note a plus sign (+) next to the test date. This indicates what about the cylinder?

A) It is made of spun aluminum, not steel.
B) It only requires a 10-year DOT inspection.
C) It can be filled to 10% above its service pressure.
D) It has a high coefficient of elastic expansion.

Question 9

What is the most common and least expensive method for commercial production of O₂?

A) Electrolysis of water
B) Fractional distillation of air
C) Physical separation by molecular sieves
D) Chemical decomposition of sodium chlorate

Question 10

By what means is O₂ for medical use in a hospital most commonly produced?

A) Chemical decomposition
B) Electrolysis
C) Fractional distillation
D) Physical separation

Question 11

What is the fire-risk classification of both N and CO₂?

A) Flammable
B) Supports combustion
C) Inflammable
D) Nonflammable

Question 12

What key property of He makes it useful as a therapeutic gas?

A) Low solubility
B) Chemical inertness
C) Low cost
D) Low density

Question 13

Which of the following medical gases support combustion?
1) O₂
2) N₂O
3) Compressed air
4) CO₂

A)1 and 4 only
B)2 and 3 only
C)1, 2, and 3 only
D)1, 3, and 4 only

Question 14

Which of the following statements about He is false?

A) It is an inert gas.
B) It is odorless.
C) It is nonflammable.
D) It is heavier than air.

Question 15

Department of Transportation (DOT) regulations require compressed gas cylinders to be hydrostatically tested for leaks and expansion every how often?

A) 1 to 2 years
B) 3 to 5 years
C) 6 to 8 years
D) 5 to 10 years

Question 16

Which of the following statements regarding O₂ are true?
1) It is only slightly soluble in water.
2) It is odorless and transparent.
3) It is flammable.
4) It is heavier than air.

A)1 and 3 only
B)1, 2, and 4 only
C)3 and 4 only
D)1, 2, 3 only

Question 17

Which of the following gases is used to treat conditions causing hypoxic respiratory failure?

A) N₂O
B) He
C) NO
D) Cyclopropane

Question 18

Which of the following are considered therapeutic gases?
1) Oxygen (O₂)
2) O₂-NO mixture
3) O₂-He mixture
4) N₂O

A)1 and 2 only
B)2 and 4 only
C)3 and 4 only
D)1, 2, and 3 only

Question 19

Which of the following statements about CO₂ are true?
1) It does not support animal life.
2) It is a flammable gas.
3) It is odorless and colorless.
4) It is heavier than air.

A)1 and 3 only
B)2 and 3 only
C)3 and 4 only
D)1, 3, and 4 only

Question 20

What factors affect the combustion-supporting properties of O₂?
1) Concentration
2) Partial pressure
3) Humidity

A)1 only
B)2 only
C)1 and 2 only
D)1, 2, and 3

Question 21

What cylinder factor is used to compute the duration of flow for a 244 cu/ft (H/K) O₂ or air cylinder?

A) 0.16
B) 0.28
C) 3.14
D) 2.41

Question 22

Which of the following medical gases can be stored in cylinders as liquids at room temperature?
1) CO₂
2) O₂
3) N₂O

A)1 only
B)1 and 2 only
C)1 and 3 only
D)1, 2, and 3

Question 23

What is the key difference between small compressed gas cylinders (sizes AA to E) and their larger counterparts (sizes F to K)?

A) Small gas cylinders do not undergo regular DOT testing.
B) Small gas cylinders are always filled to lower pressures.
C) Small gas cylinders cannot be used for anesthetic gases.
D) Small gas cylinders use a yoke (not threaded) connector.

Question 24

The measured pressure in a liquid-filled cylinder is equivalent to which of the following?

A) The force necessary to compress its volume within the cylinder
B) Its filling density divided by the cylinder gas factor
C) The pressure of the surface vapor at any given temperature
D) The weight of the liquid divided by the density of water

Question 25

When full, a gas cylinder registers a pressure of 2200 psig. After a few hours of use, the pressure gauge reads 550 psig. The cylinder is now how full?

A) One-half
B) One-third
C) One-fourth
D) Two-thirds

Question 26

When using a Bourdon gauge against high outflow resistance, what will the flowmeter reading show?

A) Exceed actual flow
B) Be less than actual flow
C) Equal actual flow
D) Equal 50 psig

Question 27

To prevent this type of accident, all cylinders have high-23. In clinical practice, how is a positive identification made of the contents of a medical gas cylinder?

A) Noting the color of the cylinder
B) Inspecting the cylinder threads
C) Reading the cylinder label
D) Collecting and analyzing a gas sample

Question 28

According to the National Institute of Standards and Technology of the U.S. Department of Commerce, a gas cylinder that is color-coded brown and green should contain which of the following?

A) O₂-N₂ mixture
B) O₂-CO₂ mixture
C) CO₂
D) O₂-He mixture

Question 29

What cylinder factor is used to compute the duration of flow for a 22 cu/ft O₂ or air E cylinder?

A) 0.28
B) 1.34
C) 2.41
D) 3.14

Question 30

According to the U.S. Department of Commerce, a gas cylinder that is color coded blue should contain which of the following?

A) Air
B) He
C) N₂O
D) O₂

Question 31

The gauge on a G cylinder of O₂ reads 400 psig. Approximately how long would the contents of this cylinder last, until completely empty, at a flow of 5 L/min?

A) 2 hr 40 min
B) 3 hr 10 min
C) 4 hr 30 min
D) 9 hr 15 min

Question 32

The gauge on an E cylinder of O₂ reads 800 psig. Approximately how long would the contents of this cylinder last, until completely empty, at a flow of 3 L/min?

A) 1 hr 15 min
B) 1 hr 45 min
C) 2 hr 10 min
D) 2 hr 40 min

Question 33

A cylinder of N₂O has a gauge pressure of 750 psig when full. What will be the pressure in this cylinder when it is half full?

A) 375 psig
B) 750 psig
C) 1500 psig
D) 2200 psig

Question 34

What is the usual method of monitoring the remaining contents in a gas-filled cylinder?

A) Weigh the cylinder.
B) Read the pressure gauge.
C) Compute the gas density.
D) Read the cylinder label.

Question 35

The measured pressure in a gas-filled cylinder is equivalent to which of the following?

A) Its filling density divided by the cylinder gas factor.
B) Gas temperature times its coefficient of expansion.
C) Gas density divided by the density of air at standard temperature, standard pressure, dry (STPD).
D) The force required to compress its volume within the cylinder.

Question 36

Which of the following mechanisms do all compressed gas cylinders use to avoid excessively high buildup of cylinder pressure?

A) Internal convection cooling mechanism
B) Pressure-relief mechanism on the valve stem
C) Automatic cylinder breech mechanism
D) Pressure-relief mechanism on the cylinder body pressure relief valves.

Question 37

Under what conditions will the gauge pressure of a cylinder of N₂O accurately represent its contents?
1) When the liquid in the cylinder has completely vaporized
2) When the ambient temperature exceeds the critical temperature
3) When the filling density is less than 1.0 (water-filled)

A)1 and 2 only
B)1 and 3 only
C)2 only
D)1, 2, and 3

Question 38

To accurately determine the remaining contents of a liquid-filled CO₂ cylinder, what would you do?

A) Multiply the pressure by the cylinder factor.
B) Divide the pressure by the cylinder factor.
C) Weigh the contents of the cylinder.
D) Empty the cylinder while timing its flow.

Question 39

Cylinders of liquid gases are filled according to what specification?

A) Filling density
B) Critical weight
C) Elastic expansion
D) Filling pressure

Question 40

The gauge on an H cylinder of O₂ reads 2000 psig. Approximately how long would the contents of this cylinder last, until completely empty, at a flow of 6 L/min?

A) 1 hr 30 min
B) 17 hr 30 min
C) 18 hr 10 min
D) 21 hr 50 min

Question 41

During inspection of the shoulder of a compressed gas cylinder, you note an asterisk (*) next to the test date. This indicates what about the cylinder?

A) It is made of spun aluminum, not steel.
B) It only requires a 10-year DOT testing.
C) It can be filled to 10% above its service pressure.
D) It has a high coefficient of elastic expansion.

Question 42

What is the primary purpose of indexed connector systems?

A) To prevent inadvertent misconnections between equipment
B) To speed making connections between equipment
C) To allow U.S. equipment to "mate" with foreign equipment
D) To provide universal connections among all equipment

Question 43

Unlike CO₂ or N₂O, O₂ cannot be stored as a liquid at room temperature but must be kept in special cryogenic containers. Why is this so?

A) O₂ is 20 times less diffusible than CO₂, N₂O, or cyclopropane.
B) O₂ has a critical temperature well below room temperature.
C) O₂ has an extremely high gas solubility coefficient.
D) O₂ has a boiling point below well below room temperature.

Question 44

You are planning a patient transport that will take approximately 1 hr. The patient requires manual ventilation with 10 L/min of O₂. What is the minimum number of full E cylinders you would take with you?

A) 2
B) 3
C) 4
D) 5

Question 45

The pressure of O₂ or air in a bulk supply system is reduced to what standard working pressure?

A) 10 psig
B) 14 psig
C) 25 psig
D) 50 psig

Question 46

What is the pin index hole position for O₂?

A) 1 and 5
B) 2 and 5
C) 1 and 6
D) 4 and 6

Question 47

Which of the following statements is FALSE about PISS standards?

A) The exact positions of pins and pinholes do not vary for each gas.
B) In order to work, the yoke nipple has to seat in the recessed valve outlet.
C) They apply only to cylinders using a yoke connection.
D) They have six pin positions and 10 possible pin/hole combinations.

Question 48

Why are zone valves incorporated into a hospital's central gas piping systems?
1) To terminate O₂ delivery to an area in case of fire
2) To allow selective maintenance without shutting the system down
3) To allow variable pressure reduction throughout the system

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1, 2, and 3

Question 49

What safety system is designed to prevent accidental interchanging among low-pressure (<200 psig) connectors such as those found on flowmeters and ventilators?

A) PISS
B) ASSS
C) DISS
D) CGA

Question 50

What is the indexed safety system for threaded high-pressure connections between large compressed gas cylinders and their attachments?

A) Pin-Indexed Safety System (PISS)
B) Diameter-Index Safety System (DISS)
C) American Standard Safety System (ASSS)
D) CGA System

Question 51

What is the greatest potential problem with quick-connect DISS systems?

A) Increased cost of flowmeter equipment
B) Decreased accuracy in flowmeter equipment
C) Difficulty in training new personnel
D) Incompatibility among different manufacturers

Question 52

One cu/ft of liquid O₂ is the equivalent to approximately how many cu/ft of gaseous O₂?

A) 28
B) 244
C) 360
D) 860

Question 53

You must connect a large-volume nebulizer to a bedside compressed-air outlet through a flowmeter. You have only standard O₂ flowmeters available. Which of the following actions is appropriate?

A) Connect the O₂ flowmeter to the air outlet with piping tape.
B) Use an O₂-to-air DISS adapter to join the flowmeter and outlet.
C) Connect the O₂ flowmeter to the air outlet with a petroleum jelly seal.
D) Try to cross-thread an O₂ flowmeter directly on the air outlet.

Question 54

Which of the following components are common to a standard compressed gas cylinder manifold system?
1) Automatic switch-over control
2) Pressure-reducing valves
3) Primary and reserve bank
4) Alarm system

A)1, 2, and 3 only
B)2 and 4 only
C)3 and 4 only
D)1, 2, 3, and 4

Question 55

What do the components of a liquid O₂ bulk storage tank include?
1) Inner and outer steel shells, separated by a vacuum
2) Safety system that vents O₂ if warming occurs
3) Vaporizer system that converts liquid O₂ to gas
4) Pressure-reducing valves to lower pressure to 50 psig

A)1, 2, and 3 only
B)2 and 4 only
C)1, 2, 3, and 4
D)3 and 4 only

Question 56

The NFPA standard for bulk liquid O₂ systems requires that the reserve supply be which of the following?

A) Fixed cylinder bank of 75 H cylinders
B) At least one large liquid O₂ cylinder
C) Equal to the average gas use of 1 day
D) At least 3000 cu/ft of gaseous O₂

Question 57

Which of the following are true about ASSS standards?
1) They provide specifications for more than 60 gases and mixtures.
2) They apply only to cylinders sizes F through H/K.
3) They apply to high-pressure connections.
4) They provide a separate connector for all gases.

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 58

Where do respiratory therapists typically find DISS connections?
1) At the outlets of pressure-reducing valves attached to cylinders
2) At the nurse station
3) At the station outlets of central piping systems
4) At the inlets of blenders, flowmeters, ventilators, and other pneumatic equipments

A)1 and 2 only
B)1, 2, and 3 only
C)1, 3, and 4 only
D)3 and 4 only

Question 59

Which device is used to reduce the pressure and control the flow of a compressed medical gas?

A) Bourdon gauge
B) Regulator
C) Flowmeter
D) Reducing valve

Question 60

Structural requirements for the central piping systems that are used in hospitals to distribute gases are established by whom?

A) American National Standards Institute (ANSI)
B) Department of Transportation
C) National Fire Protection Association (NFPA)
D) Compressed Gas Association (CGA)

Question 61

Which of the following are advantages of using a flow restrictor to control the delivery of medical gases to a patient?
1) Preset metered flow
2) Low cost and simplicity
3) Gravity independence
4) Wide range of utility

A)1, 2, and 3 only
B)1, 2, and 4 only
C)2 and 4 only
D)3 and 4 only

Question 62

When used to control the flow of medical gases to a patient, how is a flow restrictor classified?

A) Variable-orifice, constant-pressure flowmeter device
B) Fixed-orifice, variable-pressure flowmeter device
C) Variable-orifice, variable-pressure flowmeter device
D) Fixed-orifice, constant-pressure flowmeter device

Question 63

You are preparing to conduct a complex transport of a patient receiving O₂, and you expect to have to alter O₂ flows during the transport. Which of the following devices would best meet your needs?

A) Uncompensated Thorpe tube
B) Flow restrictor
C) Compensated Thorpe tube
D) Bourdon gauge

Question 64

When minimal fluctuations in pressure and flow are critical factors, which of the following pressure-reducing valves would be the best choice?

A) Single-stage preset pressure-reducing valve
B) Multiple-stage pressure-reducing valve
C) Uncompensated Thorpe tube flowmeter
D) Bourdon adjustable pressure regulator

Question 65

If you have to deliver medical gas to a patient from a compressed gas cylinder, which of the following devices would you select to control gas flow?

A) Regulator
B) O₂ blender
C) Reducing valve
D) Flowmeter

Question 66

Which of the following is true about an uncompensated Thorpe tube?

A) Flow lower than actual if downstream pressure increases
B) Fixed-orifice, variable-pressure flowmeter device
C) Flow-control needle valve placed distal to the flow tube
D) Accuracy unaffected by changes in downstream resistance

Question 67

Which of the following are true about a Bourdon gauge?
1) It is always used with an adjustable high-pressure reducing valve.
2) It actually senses pressure but is calibrated to display flow.
3) It reads a flow higher than actual if downstream pressure increases.
4) It will register zero flow when the outlet is completely blocked.

A)1 and 3 only
B)1, 2, and 3 only
C)3 and 4 only
D)2, 3, and 4 only

Question 68

You are called by a nursing home to help set up O₂ for a patient, delivered through a jet nebulizer. Unfortunately, all that is available is an old uncompensated Thorpe tube flowmeter. When set to 8 L/min, the nebulizer creates an additional 30 psig of downstream pressure. Approximately what flow of O₂ will the patient now receive?

A) 4 L/min
B) 6 L/min
C) 8 L/min
D) 12 L/min

Question 69

What is the only major factor limiting the use of pressure-compensated Thorpe tube flowmeters?

A) Downstream resistance
B) Effect of position (gravity)
C) DISS connector availability
D) Use with gases other than O₂

Question 70

Helium must always be combined with at least how much O₂?

A) 20%
B) 30%
C) 40%
D) 50%

Question 71

When used to control the flow of medical gases to a patient, how is a Thorpe tube classified?

A) Variable-orifice, constant-pressure flowmeter device
B) Fixed-orifice, constant-pressure flowmeter device
C) Variable-orifice, variable-pressure flowmeter device
D) Fixed-orifice, variable-pressure flowmeter device

Question 72

To clean a cylinder valve outlet of foreign material, what should you do?

A) Wipe the valve outlet with a light oil.
B) Quickly open and then close the valve.
C) Blow into the valve outlet a few times.
D) Wipe the valve outlet with an alcohol swab.

Question 73

If you have to deliver O₂ to a patient directly from a bedside outlet station, which of the following devices would you select?

A) Thorpe tube flowmeter
B) Bourdon-type gauge
C) Pressure-reducing valve
D) Medical gas regulator

Question 74

Which of the following is false about a compensated Thorpe tube?

A) Variable-orifice, constant-pressure flowmeter device
B) Calibrated in liters per minute at atmospheric pressure
C) Flow-control needle valve placed distal to the flow tube
D) Accuracy unaffected by changes in downstream resistance

Question 75

How can one determine whether a pressure-reducing valve uses multiple stages for pressure reduction?

A) By noting the number of gauges attached to the valve
B) By noting the DISS code
C) By noting the ASSS code
D) By noting the number of pressure relief vents

Question 76

When used to control the flow of medical gases to a patient, how is a Bourdon gauge classified?

A) Fixed-orifice, variable-pressure flowmeter device
B) Fixed-orifice, constant-pressure flowmeter device
C) Variable-orifice, variable-pressure flowmeter device
D) Variable-orifice, constant-pressure flowmeter device

Question 77

A very common application of the adjustable pressure-reducing valve is in combination with which of the following?

A) Flow restrictor
B) Thorpe tube flowmeter
C) Bourdon gauge
D) Uncompensated flowmeter

Question 78

Which of the following devices would you select if the goal was to accurately meter the flow through a jet nebulizer?

A) Bourdon gauge
B) Flow restrictor
C) Uncompensated Thorpe tube
D) Compensated Thorpe tube