Medical Gas Systems Flashcards
1
Q
Medical Gas systems primary source is _______and _________
A
Central supply (primary source) Cylinders attached to the machine
2
Q
Tanks (cylinders) are _______with ______SS
A
Color coded, pin indexed
3
Q
What is the role of the valves
A
Attach cylinders to the hanger yoke with a T handle
4
Q
Some caution about Safety?
A
Gas stored at high pressure, use caution!!
Disconnect, supply failure
5
Q
What are the different types of Gases:
ONANCH
A
Oxygen N2O Air Carbon Dioxide Nitrogen Helium
6
Q
Oxygen Medical grade % of purety?
A
99 - 99.5% pure
7
Q
N2O
A
Anesthetic gas
8
Q
Air Medical Grade
A
Dehumidified
9
Q
Carbon Dioxide used in
A
Laparoscopic procedures
10
Q
Nitrogen
A
Provides power to equipment
11
Q
Helium
A
Used in laser surgery of the
airway to reduce fire risk
12
Q
What are the pipeline systems and which one is the most common?
A
Pipe line systems
Central supply
Pipelines (Most common)
Connectors
13
Q
Potential problems with Pipeline systems (CIEA)
A
- Contamination (particles, bacteria, viral, moisture,
Bioterrorism) - Inadequate pressure
- Excessive pressures
- Accidental crossover (switch between oxygen and some
other gas such as nitrous oxide or nitrogen)
14
Q
Tanks and cylinders Standards (FACNUQ)
A
Standards US Department of Transportation Compressed Gas Association National Fire Protection Association American Society of Mechanical Engineers Food and Drug Administration Quality and purity of contents.
15
Q
Tanks and cylinders Sizes most commonly used for anesthesia
A
Sizes most commonly used in anesthesia
E cylinder on back of machines
H cylinders chained to walls
D cylinders for transport
16
Q
Color coding
A
US colors
International colors
17
Q
Central supply is a
A
series of tanks connected by a manifold or pressurized vessels of liquid O2.
18
Q
Oxygen \_\_\_\_\_\_vs white Air \_\_\_\_\_\_vs black and white Nitrous Oxide is\_\_\_\_ CO2 is gray Nitrogen is\_\_\_\_\_\_
A
green
yellow
blue
black
19
Q
The definitive indicator is always
A
the label.
20
Q
Nonliquefied Compressed Gas
A
Do not liquefy at ordinary temperatures and pressures from 2000 to 2500 psi
Oxygen
Nitrogen
Helium
21
Q
Nonliquefied Compressed Gas
Do not liquefy at ______and _______from ______to ______psi
A
Do not liquefy at ordinary temperatures and pressures from 2000 to 2500 psi
Oxygen
Nitrogen
Helium
22
Q
Liquefied Compressed Gas
A
Becomes a LIQUID at pressures from 25 to 2500 psig
Nitrous oxide
Carbon dioxide
23
Q
PISS Air: Nitrogen: N20: Oxygen:
A
1-5
1-4
3-5
2-5
24
Q
Tanks must be inspected
A
every 10 years
25
What is the boiling point
Boiling point is (the temperature where gas turns to a liquid or liquid turns to a gas)
26
What is the boiling point of Oxygen
Bp for O2 = –183 C at atmospheric pressure (=760 torr STP = 0 degrees at 760 torr)
27
What is Critical Temperature?
– temperature below which a gas is converted to a liquid form by pressure.
28
Each gas changes to a ____at a known.
liquid ; critical temperature and critical pressure
29
Critical pressure
the pressure required at critical temp to keep the gas in its liquid form.
30
For example Critical temp for O2 is ______
| Pressure must be _____psia. This means that
–119C. 737; O2 can only be stored as a gas at room temp. Room temperature is about 20 C
31
Oxygen is Manufactured by_________
fractional distillation of liquefied air.
32
Oxygen is Stored as_________or -_________as _____ at ____ to _____C
compressed gas, or refrigerated as liquid at -150 to -175 °C.
33
What is the most widely used drug in the US.
Oxygen
34
Why is oxygen special property?
Strong oxidizing agent, supports combustion, labeled as a hazardous material.
Also used to power anesthesia ventilators
35
Volume of gas of O2
| ______ liters of gas and ______psig
660L;
| 1900 psig
36
What gas law governs tank pressures?
Boyle’s law – P1V1= P2V2
37
What is the internal volume of the oxygen tank?
5L
38
Empty weight?______
| Full weight _______ (O2 weighs _____)
Empty – 9-14 lbs (depending on material)
| Full- approx 15 ½ lbs (O2 weighs 1 lb, 6 oz)
39
O2 tank pressure when full is
1900 psig
40
Pressure gauges indicates the_________
| In the case of oxygen, this enables what ?.
pressure within each cylinder.
| the estimation of the contents since the amount of gas contained in the cylinder is proportional to the pressure
41
There is a range of values reported for E cylinders that goes from______ We want you to use
1900 to 2200.
| 1900.
42
For the H tank Volume of gas
Interval volum is ________
PSI is _______
Volume of gas
Internal volume = 43.6 liters
PSI 1900
Liters of Oxygen = 6900
43
How many liters of Oxygen in " H" tank
6900 Liters
44
Nitrogen is Stored as a______, at__________temperature in large tanks (_____, _ tank) connected to a manifold which _________to approximately
liquid ; ambient temperature; 745 psi – H tank) regulates the pipeline pressure; 50 psi
45
Molecular Weight of N2O
44
46
Boiling point of N2O
- 88 °C
47
Critical temperature of N2O
36.5 °C
48
Critical Pressure of N2O
1054 psig
49
N2O can exist
As a liquid in room temperature
50
N2O Weight when TANK Empty is _______, approx________
Stamped on side; 14 lb
51
Weight when TANK is Full : ______N2O and _______lbs =
Approx 6 lb 6 oz nitrous + 14 lb = 20 lb, 6 oz
52
N2O =____psi until
745 psi until all N2O is liquid
53
Nitrous oxide are liquified by the
high pressure within the cylinder.
54
About the Nitrous oxide tanks pressure
-Pressure remains relatively constant until all the liquid is evaporated, after which the pressure drops rapidly as the remaining gas is removed.
55
The contents of these Nitrous oxide cylinders can only be estimated by
weighing the cylinder.
56
N2O Tanks are filled tohe saturated vapor pressure of N2O is 745 psi.
90-95% capacity.
57
The area above the liquid is filled with N2O
vapor.
58
Use Avogadro’s Volume which states that
1 gram molecular weight of any gas or vapor occupies 22.4 L at STP.
59
Medical Air for breathing
No detectable liquid hydrocarbons
| Less particulates than in the atmosphere
60
Air Contains ____nitrogen, and_____ oxygen
| Usually supplied at pressure of
~79%; ~21%
| 1900-2200 psi
61
```
YOKE: Safety release devices needed for______and ________
FUSIBLE PLUG (Wood’s metal) has a_____________ which _________
```
Can use a combo ie the safety relief valve and fusible plug. The valve vents are filled with Wood’s metal
high tank pressures and overheated tanks
| low melting point which melts in a fire
62
Frangible Disc Assembly is a
metal disc that breaks when a certain pressure is exceeded
63
What is the safety relief valve
releases gas after set pressure is exceeded
64
Can use a combo ie _______
| the valve vents are filled with ______
he safety relief valve and fusible plug. The valve vents are filled with Wood’s metal
65
Oxygen Cylinder ValveSmall Tank 7 parts
1. The body
2. The port
3. The valve stem
4. The handle/key
5. Safety relief device
6. The conical depression
7. Noninterchangeable safety systems: prevent attachment of the incorrect cylinder to a yoke
66
What is the role of the oxygen cylinder valve BODY?
Forms the basic structure. Screws into the tank. DISS/hole size vary for safety
67
What is the role of the oxygen cylinder valve PORT?
where the yoke attaches to allow for exit of the gas.
68
What is the role of the oxygen cylinder valve VALVE STEM
when opened allows gas to exit tank
69
What is the role of the oxygen cylinder valve HANDLE KEY
turns the valve stem
70
What is the role of the oxygen cylinder valve SAFETY RELIEF DEVICE
allows discharge of the cylinder contents under certain conditions (do not confuse with the conical depression)
71
What is the role of the oxygen cylinder valve CONICAL DEPRESSION
(on small cylinder valves) receives the retaining screw of the yoke
72
What is the role of the oxygen cylinder valve NON INTERCHANGEABLE SAFETY SYSTEMS?
prevent attachment of the incorrect cylinder to a yoke
73
Gas specific connectors are used on large (G and H) cylinders that make it
impossible to attach a regulator or fitting to the wrong cylinder.
74
Connections for large cylinders
Varied thread connections
| Varied hole sizes for body of cylinder valv
75
```
Pin Index Safety System
Prevents ______
How many pins?
How many positions?
How many possible variations?
```
```
Prevents attachment of an incorrect cylinder to a yoke
Used on E tanks or smaller
2 pins on yoke
7 positions
13 possible variations
```
76
Small Cylinder Safety
Gas specific pin-index system
Pins on yoke of anesthesia machine mate with holes drilled in specific locations on valve of cylinder.
Provides a mechanical means of preventing incorrect connection.
77
Diameter Index Safety System (DISS)
Removable non-interchangeable connections for low pressure lines
78
DISS role
Prevents connection of gas-administering equipment to the wrong type of gas
79
DISS consists of
Consists of a body (female end), nut, and nipple (male end)
Each are varied in size
Threads widths are varied
Example: wall outlet connectors
80
Quick Couplers
Safety keyed to be gas specific
81
Safety considerations
aluminum cylinders
one washer
oil valve.
Protect the valve
Use only in an MRI suite.
Use only ________or PISS system will be defeated.
Do not _____the valve; when transporting.
82
For tanks NEVER STAND
Never stand upright without support.
83
To install
Check & remove labels
Hold valve away from face, and "crack" valve
Place in hanger yoke
Observe for appropriate pressure and lack of audible leak.
84
Leave cylinders on machine
closed.
85
Calculations of cylinder duration
(P1V1 = P2V2)
86
E cylinder reading 800 psi. Flow rate 15 l/min per ambu bag. How many minutes do you have before patient runs out of oxygen?
Calculate
87
Formula
Actual gauge reading (psi) X (known liters full) (total liter flow)
Initial filling pressure (psi)
88
Formula
Actual gauge reading (psi) X (known liters full) / (total liter flow) (Initial filling pressure )(psi)
89
For O2 tank use:
| To determine time left in tank:
PSI X constant / = minutes left before empty
| L/M
90
Constants: (for oxygen tanks only)
D= ___ (used for ____)
E=____
H=___
```
D = 0.18 (helicopter transportation)
E = 0.30
H = 3.14
```
