Resp. equipment Chapter 3.

Question 1

Air

Answer 1

-At ATM cond. is colorless, odorless gas mixture that contains water vapor
-Air contain 78% nitrogen and 21% O2
- Trace gases in the AIR- argon, carbon dioxide, neon, helium, methane, Kryton, Nitrous oxide, xenon that make up the reamaining 1% of ATM air.
- Non- flammable gas but support combustion.
- Density of 1.29 kg/m^3 at 21.1C (70F) and 760mmhg.
- Air is used as a standard for measuring the SPECIFIC Gravity of to other gases, assigned value of 1 at 21.1C and 1 ATM.
- freezing point is -195.6C (-320F)
- Transparent liquid with a pale bluish cast.
- Compressed air is prepared synthetically from nitrogen and oxygen and shipped as a Gas in cylinders at high pressure.
-Liquid air can be obtained through process called Liquefaction
- shipped in bulk in specially designed Cryogenic containers.

Question 2

Oxygen

Answer 2

• is an elemental gas that is colorless, odorless, and tasteless at normal temp.
• It makes up 20.9% of the Earth’s ATM by volume and 23.2% by weight.
  -It constitutes approx. 50% of the earth’s crust by weight
• Density of 1.326 kg/m^3 at 21.1C and 760mmhg
• specific gravity = 1.105
  -At temp. less than -183C (-297.3 F) oxygen exists as pale bluish liquid that is slightly heavier than water.
• non-flammable but support
  -All elements except the inert gases combine with oxygen to form oxides; oxygen therefore is characterized as an oxidizer.
• The two methods most commonly used to prepare oxygen are the Fractional distillation of liquid air and the Physical separation of ATM air.
• Fractional distillation process is used commercially to produce bulk oxygen, which can be stored as liquid in cryogenic storage tanks or converted into a gas and shipped in metal cylinders
• Physical separation of ATM air accomplished with devices that use molecular sieves and semipermeable membranes to filter room air. These devices are called Oxygen Concentrators, are used primarily to provide enriched oxygen mixtures for oxygen therapy in the home care setting.

Question 3

(oxygen)_ Fractional Distillation of liquid Air

Answer 3

1. Room air is drawn through scrubbers to remove dust and other impurities
2. Air is cooled to near the freezing point of water ( 0C) to remove water vapor
3. Air is compressed to 200 ATM, causing the temp of gas mixture to increase.
4. Compressed air is cooled to room temp. by passing nitrogen through coils surrounding the gas mixture.
5. As the temperature drops, the gas mixture expands. The temperature achieved is less than the critical temperature of nearly all gases in air, and a liquid gas mixture is produces
6. The liquid air is transferred to a distilling column, where it is warmed to room temp. As the air warms, various gases boil off as their individual boiling points are reached.
7. liquid oxygen is obtain by maintaining the temperature of the gas mixture just below the boiling point of oxygen (-183C) (-297.3) at 1 ATM
8. The process is repeated until the liquid oxygen mixture is 99% pure with no toxic impurities
9. The liquid oxygen is transferred to cold converters for storage and later transported wither in bulk as liquid or in compressed-gas cylinders as a gas.

Question 4

Carbon Dioxide (Co2)

Answer 4

• Colorless, odorless at normal atm.
• Density of 1.833 Kg/m^3 at 21.1C and 1atm
• 1.5 times heavier than air ( specific gravity = 1.522)
• Exist as solids, liquid and gas at temp. of - 56.6C (-69.9F) and a pressure of 60.4 psig ,carbon dioxide’s triple point.

Question 5

Carbon dioxide as Solids

Answer 5

temp. and pressure below its triple point, carbon dioxide exist as solid (dry ice) or gas depending on the temperature.

Question 6

Carbon dioxide as liquid

Answer 6

temp. and pressure above its triple point but below its critical temperature ( 31.1C or 87.9 F)
- when carbon dioxide is stored at these temp. in a pressurized container, such as metal container, the liquid and gaseous forms of carbon dioxide exist in equilibrium.
Above 31.1C, carbon dioxide cannot exist as liquid.

Question 7

Unrefined carbon dioxide can be obtained from

Answer 7

combustion of coal, natural gas, or other carbonaceous fuels.
- by product in the production of ammonia, lime, and kilns, among other products.
purified carbon dioxide is prepared through the liquefaction and fractional distillation processes.

Question 8

Solid carbon dioxide

Answer 8

is used to refrigerate perishable materials while in transport.

Question 9

Liquid carbon dioxide

Answer 9

can be used as an expendable refrigerant and is used extensively as a fire-extinguishing agent

Question 10

Gaseous carbon dioxide

Answer 10

is use in food processing ( carbonation of beverages ) and water treatment, and as a growth stimulant for plants.

Question 11

Carbon dioxide - oxygen mixtures

Answer 11

• Combining 5% to 10% carbon dioxide with 90-95% oxygen.
• It is important to recognized that breathing carbon dioxide-oxygen mixture can have adverse effect on other medication such as bp medications, muscle relaxant, chemotherapy drugs, and antibiotic.

Question 12

carbon dioxide is also used in

Answer 12

pulmonary diagnostic testing as a standard calibration gas for blood gas analyzer, transcutaneous partial pressure of carbon dioxide ( PCO2) electrodes, and capnographs

Question 13

Helium (HE)

Answer 13

-second lightest element
-density of 0.165 kg/m^3 at 21.1 C and 1 atm ( specific gravity=0.138)
- It is an inert gas that has no color, odor, or taste.
- slightly soluble in water and is a good conductor of heat, sound , electricity.
- Helium combined with oxygen to deliver oxygen therapy to Pt with severe airway obstruction. ( decrease the work of breathing by decrease turbulent airflow)
- It also used in pulmonary function testing to measure residual volume and diffusing capacity.

Question 14

Nitric oxide (NO)

Answer 14

-Diatomic molecule that exists as colorless gas with a slight metallic odor at room temp.
- Density of 1.245kg/m^3 and specific gravity of 1.04
-Nitric oxide is highly unstable in the atmosphere and can exist in three biologically active forms in tissues Nitrosoium (NO^+), Nitroxyl anions (NO^-) and as free radical (NO^.)
- In presence of air nitric oxide combines with oxygen to form brown fumes of nitrogen dioxide (NO2), a strong oxidizing agent. (not corrosive)
- In presence of moisture, it can form nitrous and nitric acids, both of which can cause corrosion.
-Nitric oxide and nitrogen dioxide combine form a potent irritant that can cause chemical penumonitis and pulmonary edema.
- Although nitric oxide is toxic in high concentration, experimental results indicate that low doses are a powerful pulmonary vasodilator.
very low concentrations combined with oxygen have been used successfully to treat persistent pulmonary hypertension of the newborn and hypoxic respiratory failure in term and near-term newborn in whom conventional ventilator therapy has failed.

Question 15

Nitrous oxide (N20)

Answer 15

• colorless gas at normal temp. ,
  odorless, tasteless, and nonflammable but will support combustion.
• slightly soluble in water, alcohol, and oils.
• oxidizing agent it will react with oils, grease, and other combustible materials.
• Nitrous oxide is prepared commercially by the thermal decomposition of ammonium nitrate and as a by-product of the adipic acid manufacturing processes. At elevated Temp (>649C or 1200F) it decomposes into nitrogen and oxygen.
• Nitrous oxide is used primarily as a central nervous system depressant ( anesthetic). Inhalation of nitrous oxide without provision of a sufficient oxygen supply may cause brain damage or be fatal
• Long-term exposure of nitrous oxide has been associcated with adverse side effects including neuropathy and fetotoxic effects ( spontaneous abortion)

Question 16

Regulating Agencies

Answer 16

• (CDRH) Center for Devices and Radiological Health, an agency of the FDA that provides standard for medical devices

Question 17

Department of Health and Human Services ( DHHS)

Answer 17

Department of the federal government that oversees health care delivery in the United states. Formerly known as the department of Health, Education, and Welfare (DHEW)

Question 18

Department of transportation (DOT)

Answer 18

Provides regulations for the manufacture, storage, and transport of compressed gases.

Question 19

Environmental Protection Agency (EPA)

Answer 19

Government agency that establishes standards and administers regulations concerning potential and actual environment hazards

Question 20

Food and Drug Administration (FDA)

Answer 20

An agency of the DHHS that sets purity standards for medical gases

Question 21

Occupational Safety and Health Administration ( OSHA)

Answer 21

An agency of the department of labor (DOL) that oversees safety issues related to the work environment.

Question 22

Transport Canada ( TC)

Answer 22

Canadian government agency that administers regulation concerning the manufacture and testing of compressed -gas cylinders and their distribution.

Question 23

Recommending Agencies

Answer 23

American National Standard Institute (ANSI)
- Private, nonprofit organization that coordinates the voluntary development of national standards in the United States. Represents US interests in international standards

Question 24

American Society of Mechanical Engineers (ASME)

Answer 24

Issues information on the design, manufacture and structural standards for components of central piping systems

Question 25

Compressed Gas Association (CGA)

Answer 25

Comprise companies involved in the manufacture, Storage, and transport of all compressed gases. Provides standards and safety systems for compressed gas systems

Question 26

International Organization for Standardization (ISO)

Answer 26

International agency that provide standards for technology

Question 27

National Fire Protection Association ( NFPA)

Answer 27

Independent agency that provides information on fire protection and safety

Question 28

United State Pharmacopeia/The National formulary (USP-NF)

Answer 28

A not-for-profit private organization founded to develop officially recognized quality standards for drugs, including medical gases

Question 29

Z-79 committee

Answer 29

ANSI committee for establishing standards for anesthetic and ventilatory devices, including anesthetic machines, reservoir bags, tracheal tubes, humidifiers, nebulizers, and other oxygen-related equipment.

Question 30

The most commonly used cylinders for medical gas therapy

Answer 30

are the E and H types
E- frequently used as a source of oxygen in emergency situations and transport
H- primary source of oxygen and other medical gases in smaller hospital that doe not have bulk liquid systems.

Question 31

D - cylinders are used for

Answer 31

storage of nitric oxide.

Question 32

Direct-acting valves

Answer 32

Contain two fiber washer and a Teflon packing to prevent gas leakage around the threads.
The term direct-acting is derived from the arrangement of movements in the valve wheel. These movements are directly reflected in the valve seat because it is one piece moved by threads
- Direct acting valves can withstand high pressure ( more than 1500 pound per square inch)

Question 33

Diaphragm valves

Answer 33

use a threaded stem in place of the packing found on the direct-acting valves. The stem is separated from the valve seat and spring by two diaphragms, one made of steel and one made of copper. When the stem is turned counterclockwise and raised because of the threading, the diaphragm is pushed upward with the stem by the valve seated and spring causing the valve to open.
- Diaphragm valves have several advantages
1. the valve seat does not turn and therefore is resistant to scoring, which could cause leakage
2. no stem leakage can occur because of the diaphragm
3. the stem can be opended with a partial rotation rather than with two turns of the wheel
Diaphragm valves generally are preferable when pressures are relatively low ( less than 1500 psi)
Ideal for situations in which no gas leaks can be allow, such as with flammable anesthetics.

Question 34

Three types of pressure-relief mechanisms

Answer 34

Rupture disks- also called a frangible disk, is a thin metal disk that rupture or buckles when the pressure inside the cylinder exceeds a certain predetermined limit.
-usually incorporate in smaller cylinders

Question 35

Fusible plug

Answer 35

is made of a metal alloy that melts when the temperature of the gas in the tank exceeds a predetermined temperature.
Fusible plugs operate on the principle that as the pressure in a tank increases, the temperature of the gas increases causing the plug to melt.
commonly used metal alloy called Wood’s metal, melting temp of 98c to 104c or 208F to 220F.
-usually incorporate in smaller cylinders

Question 36

Spring-loaded devices

Answer 36

are designed to release excessive cylinder pressure and reseal, preventing further release of gas from the cylinder after the cause of the excessive pressure is removed.
- more susceptible to leakage around the metal seal.
-affected by changes in environment condition.
- usually found in larger cylinders

Question 37

Piping Systems

Answer 37

Gases stored in central supply units are distributed to various sites or zones
-Pressure- regulating devices located between the bulk and the main supply lines must be capable of maintaining a minimum delivery pressure of 50psi to all station outlets at the maximum delivery line flow.
- Pressure-relief valves should be installed downstream from the mainline pressure regulator.
- A pressure-relief valve should also be installed upstream of any zone valve to prevent excessive pressure in a zone where the shutoff valve is closed.
- All pressure-relief valves are set 50% higher than the system working pressure.

Question 38

Piping system are organized into zones

Answer 38

which allow for quick isolation of all independent areas if maintenance is required or in care of a fire, affected zones can be isolated

Question 39

Shutoff - valve

Answer 39

located at the point where the main line enters the hospital, at each riser, and between each zone and the main supply line.
- Zone shutoff valves for oxygen must be located outside of each critical care unit.
-Shutoff valves for every oxygen or nitrous oxide line must also be located outside of each surgical suit.

Question 40

Station outlets

Answer 40

provide connections for gas delivery device, such as flowmeters and mechanical ventilators. These outlets consist of a body mounted to the supply line, an outlet faceplate and primary and secondary check valves, which are safety valves that open when the delivery device’s adapter is inserted into the station outlet and close automatically when the adapter is disengaged from the outlet.
Two safety systems are currently available. Diameter index safety system ( DISS) and quick-connect adapters.

Question 41

Diameter index safety system ( DISS)

Answer 41

design by CGA, uses noninterchangeable, threaded fitting to connect gas- powered devices to station outlet.
-Delivery lines that serve anesthetic devices must have a backflow of gas into the system and the check valves must be able to hold a minimum of 2400 psi.

Question 42

Quick- connect adapters

Answer 42

Uses a plunger that is held forward by a spring to prevent gas from leaving the outlet. Insertion of the appropriate adapter pushes the plunger backward, allowing gas to flow into the striker and into the equipment attached to the adapter. When the adapter is removed, the spring resets the plunger and closes the outlet.

Question 43

1. Which of the following is classified as a nonflammable gas that does not support combustion?

Answer 43

B. Carbon dioxide

Question 44

2. Medical gas cylinders are color coded for easy identification. E cylinders of carbon dioxide are painted.

Answer 44

D. Gary

Question 45

3.A Respiratory therapist is having trouble attaching a regulator to an E cylinder. One possible cause might be

Answer 45

C. The pin positions of the regulator are not the same as those on the cylinder

Question 46

4.Bulk liquid oxygen supplies should not be closer than _____ to public sidewalk

Answer 46

D. 10 feet

Question 47

5.Calculate the duration of liquid oxygen supply if the liquid supply weights 30lbs and the oxygen demand is 4L/min

Answer 47

D. 43hrs

Question 48

6.What is the duration of oxygen flow from an H cylinder containing 1200 psi of oxygen when the flow to a nasal cannula is 4L/min

Answer 48

C. 15 hours, 42 mins

Question 49

7. Large piston air compressors used in bulk supply system typically can provide working pressure of

Answer 49

A. 50psi

Question 50

8. Alternating supply systems for medical gases that are used in hospitals should include a reserve supply for oxygen in case the primary system fails.
   How much reserve oxygen should be available

Answer 50

B. An average day’s supply

Question 51

9. Oxygen concentrators that use semipermeable membranes usually can provide what percentage of oxygen at flows of 1 to 10 L/min?

Answer 51

b. 40%

Question 52

10. The percentage of oxygen delivery provided by molecular sieve O2 concentrators depends on which of the following factors?

Answer 52

B. The rate of gas flow and the age of the sieve beds

Question 53

11. The pressure inside a cylinder increases dramatically when the cylinder is exposed to extremely high temperatures. What prevents cylinders with frangible disks from exploding when exposed to extremely high temperatures?

Answer 53

a. The frangible disk ruptures from the increased pressure, allowing gas to
escape from the cylinder

Question 54

12. A respiratory therapist is checking cylinder markings to determine whether any of the cylinders need to be tested. The labeling reads as follows:
    9 83+
    6 94+

Answer 54

(b) The time between the test dates shown exceeds recommendations.

Question 55

13.Before using an H cylinder of oxygen, a respiratory therapist opens it, and gas at high pressure comes out of the cylinder outlet. Which of the following
statements is true?

Answer 55

c. This action clears debris from the connector.

Question 56

14. A respiratory therapist is helping design a new hospital wing. Which of the following agencies should be contacted so that the piping system of oxygen
    and air is correctly installed?

Answer 56

a. NFPA

Question 57

15. A hospital uses a large air compressor system to supply air through its piped
    gas lines. This gas will be free of pollutants found in the local environment.
    True or false? Why?

Answer 57

False. The compressor will draw air in from the local environment and
therefore will contain pollutants that may contaminate the local environment

Question 58

Construction and maintenance of compressed-gas cylinders

Answer 58

• Type 3AA cylinder are produced from heat-treated, high-strength steel
• Type 3A are made of carbon-steel (none heated treated)
• Type 3Al cylinders are constructed of specially prescribed seamless aluminum alloys.
• Type 3 cylinders made of low-carbon steel, no longer produced.
  Note that steel used in the construction of cylinders must meet the chemical and physical standards set by the DOT ( in canada spec are set by Tranport canada.
• Compressed-gas cylinders should be capable of holding up to 10% more than the MAX. service pressure as marked, account for pressure occur with Ambient temp.
• Bureau of alcohol, tabacco, firearms, and explosives (ATF) requires that all cylinders contain a pressure-relief mechanism to prevent explosion
• Type 3AA and 3A cylinders must be hydrostatically tested every 10years to determine their expansion characteristic
• Type 3Al cylinders must be reexamined every 5 years to test their expansion characteristics

Question 59

Hydrostatic examination

Answer 59

involves measuring a cylinder’s expansion characteristics when it is filled to a pressure of five-thirds its working pressure.
- placing a cylinder filled with water in a vessel that is also filled with water
-when pressure is applied to the interior of the cylinder, the cylinder expands, displacing water from the jacket surrounding the cylinder.
- the volume of water displaced when pressure is applied equals the volume equals the total expansion of the cylinder.
- the permanent expansion of the cylinder equals the volume of water displaced when the pressure is released.
- this information is used to calculate the elastic expansion of the cylinder, which is directly related to the thickness of the cylinder.

Question 60

Filling of medical cylinders

Answer 60

regulated by DOT, FDA and USP-NF

Question 61

The process of filling and refilling gas cylinders involves four steps

Answer 61

• cylinder prefill inspection
  -cylinder filling
  -postfill procedure
• appropriate documentation

Question 62

oxygen pin position

Answer 62

2-5

Question 63

He/O2 (He < 80%) pin position

Answer 63

2-4

Question 64

He/O2 (He >80%) pin position

Answer 64

4-6

Question 65

Storage of compressed gas cylinders

Answer 65

1. storage room must be dry, cool, ventilated, should not exceed temp of 51.67C (125F)
   - fire resistant
   - must be group by content
   - store upright
   - store with protective caps

Question 66

transportation of cylinders

Answer 66

use protective valve caps.
-must not be dropped, dragged, slid or allowed to strike with.
-transport appropriate cart secured by chain or staps