Exam 3 Compressed Gases and Vaporizers [7/1/2024] Flashcards
1
Q
What are the 2 ways cylinders are used?Give examples of each
A
-
Primary source
- tank: taking off the wall source and using tank for transport.
-
Emergency source:
- if pipeline fails, then tanks on back of anesthesia machine can be used.
S2
2
Q
Cylinders are marked by color in the US, what are the main colors?
A
- Green = Oxygen
- Blue = Nitrous
- Yellow = Air
- White = Suction
S2
3
Q
PSI stands for
A
Pounds per square inch
S3
4
Q
what is a non-liquifed gas?
A
a gas that does not liquefy at oridnary ambient temperatures regardless of the pressure applied
S3
5
Q
What were examples of non-liquifed gases?
A
- Oxygen
- Nitrogen
- Air
- Helium
S3
6
Q
What is liquifed gas?
A
- a gass that becomes liquid to a large extent in containers at ambient temperature and at pressures from 25-1500psi
S3
7
Q
A liquified gas can become a liquid at ambient temperature and at pressures from ____- _____psi
A
- 25 to 1500 psi
S3
8
Q
What were examples of liquified gases?
A
- Nitrous oxide
- Carbon dioxide
N2O is used more than CO2
S3
9
Q
What does the government do with gas cylinders?
A
They create:
* rules for building compressed gas
* building cylinders
* checking pressure in the cylinders, and
* cleanliness
S4 lecture
10
Q
What government agencies are involved with compressed gases used in the OR?
A
- FDA
- Department of Transportation [DOT]
- Department of Labor/OSHA
- National Fire Protection Association
S4
11
Q
What does the FDA do for gas cylinders?
A
puirty of substance
S4
12
Q
What does the DOT do for gas cylinders?
A
- marking
- labeling
- storage
- handling
Mark Handles Storage Label DOTS
| S4
13
Q
What does the dept of labor/OSHA do for gas cylinders?
A
- employee saftey
if tank explodes and hits someone they get involved
S4
14
Q
what does the national fire protection association do for gas cylinders?
A
- Gas combustion
Gasses [O2 esp] supports combustion [doesnt cause it]
S4
15
Q
Name the components of the cylinder/tank:
A
- Body
- Check valve
- Handle
- Pressure Relief Device
S5-6
16
Q
Body
What is the body of the cylinder made out of?
A
- Steel
- Steel Carbon Fiber
- Aluminum
S5
17
Q
The body of the cylinder has what kind of base?
A
- Flat Base
- Concave Base
S5
18
Q
Body
The body of the cylinder has a neck with what?
A
screw threads where tubing can be screwed on
S5
19
Q
The cylinder/tank has a check valve. What is this made out of?
A
- Bronze
- Brass
S5
20
Q
Where is the check valve located?
What is the function of the check valve?
A
- Location: The valve is attached to the neck of the cylinder.
- Function: allows refilling and discharge of gas
S5
O2 tanks are now refilled away from the facility.
21
Q
What is used to open/close the cylinder?
A
- Handle
- Handles should be attached to EVERY cylinder
S6
22
Q
What is another name for pressure relief device?
What is the function of the pressure relief device on the cylinder/tank?
A
- Another name: Safety Relief
- Function: It vents cylinder contents to the atmosphere if pressure increases to a dangerous level (overheating or filling)?
S6
23
Q
The pressure relief device [safety relief] allow excess pressure out of cylinder via 3 different methods. List the 3 methods.
A
- Disc that bursts
- Fusible plug melts
- Valve opens
S6
24
Q
How does the Pin Index Safety System (PISS) prevent the crossover of the wrong cable/tank into the wrong hanger?
A
- Holes on the cylinder valve positioned in an arc below the outlet part
- Pins on the yoke or pressure regulator are positioned to fit into these holes
S7
25
What is the purpose of the pin index safety system (PISS)?
* Prevents crossover of wrong cable/tank into the wrong hanger.
* Prevents turning on the wrong gas thinking it’s a different gas.
*Example: if we have a pin in 2,5 and thats oxygen. That’s the pin located for every O2 tank in the US.*
| S7 lecture
26
* How are cylinder sizes labeled?
* What is the most common cylinder size on anesthesia machines?
* A (smallest) to H (largest)
* Cylinder size E on anesthesia machines
| S8
27
What size cylinders are used for transport?
* Cylinder size D are used for transport
If we are **D**riving the pt somehwere, we need cylinder **D**
| S8
28
Cylinders supply gas to the machine at approximately what pressure? And In order to supply pressure, the cylinder must remain ____.
* Pressure from cylinder to machine is **approx 45 psi**
* must remain closed
| S8
29
with non-liqudiefied gas what happens to pressure as volume decreases?
* pressure decreases as volume decreases
| S9
30
What is the **content** and **pressure** of the oxygen tank on an anesthesia machine in the following scenarios:
1. Full Tank:
2. Half Full
3. Quarter Full
4. Empty
1. **Full Tank:**
* 600L
* 1900 PSI (1900-2200)
2. **Half Full**
* 330L
* 950 PSI
3. **Quarter Ful**l
* 165L
* 475 PSI
4. **Empty**
* 0L
* 0PSI
31
With nonliquified gases, know how to determine how much time is left in a cylinder.
A tank contains 300L, and is running at 2L/min. How many hours can this tank last?
MATH:
1. Figure out how much is used per hour.
2. 2L/min x 60 min = 120L/hr
3. Divide avalible by whats needed
4. 300L/120LperHr = 2.5 hours
| S9 lecture
32
For liquefied gases, what does the pressure depends on? What is the significance of this?
* Pressure depends on **vapor pressure**
* This makes pressure NOT an indication of remaining volume.
*In a liquefied gases there is no relationship between PSI and volume*
| S10
## Footnote
Note the full and half tank of Nitrous, but tanks have a pressure of 745 psi. Pressure is not an indicator of volume for liquefied gase.
33
# Nitrous
In Liquefied gases there is no relationship between PSI and volume. List the liquied gas PSI and volume [for math purpose]:
1. Full tank
2. Half tank
3. No liquid remaining
4. Near Empty
1. **Full tank**:
2. 1590L
3. 745 PSI
2. **Half tank:**
3. 745 PSI
3. **No liquid remaining**
4. 250L
5. 745 PSI
4. **Near Empty**
5. 125L
6. 350 PSI
| S10 lecture
34
* If the tank of nitrous has 1500L of volume, what is the PSI?
* A half full tank of nitrous, and giving 2L/min. How long will it last?
* PSI is 745 PSI
* Half Full is 750L.
* Using 120L/hr.
* 750L/120Lperhr = **6.25 hours**
## Footnote
Since nitrous is a liquified gas, we need more information per Kane that she will provide on the test. For example, a full tank has 1500L then from there we can assume half would be 750. But memorize the picture.
35
What are the Department of Transportation (DOT) regulations for cylinders?
* Diamond shaped label indicating hazard of gas…danger, warning, or caution
* Expiration date of contents
* Name and address of manufacturer
* Test date
* Service pressure
DOTS looks for **DENTS**
| S11
36
# Cylinder Standards:
Valves, regulators, gauges never come into contact with what?
* Oil
* Grease
* Lubricants
*Esp the neck, the safety relief, and on/off pin*.
| S12
37
# Cylinder Standards:
Never subject cylinder to temps above ______
* 54 C (130 F)
| S12
38
# Cylinder Standards:
Never cross use what?
* Hoses
* Regulators
* Gauges
| S12
39
# Cylinder Standards:
What must not be altered?
* Original Markings on Cylinder
* Original Labels
| S12
40
Other Cylinder Standards:
1. What should be ensured with connections?
2. What should not be done with a cylinder?
3. How should valve be kept?
4. properly secured to prevent what?
Other Cylinder Standards:
1. Connections are always tight
2. Cannot be dropped, drug, slid
3. Valve kept closed at all times
4. Properly secured to prevent fall
| S12
41
Describe the conditions of storage rooms for cylinder tanks.
* Wrapping, drapes undesireable
* Full tanks separated from empty tanks
* Adequate ventilation
* Not exposed to corrosive chemicals, fumes
* Signs: “No smoking,” or “No Combustibles”
* Stored upright in bins
Storage should be **W**/**FANSS**
| S13
42
Things to consider/do prior to using gas cylinders.
* Inspect: label, pin index holes, regulator, valve outlet
* Check if washer is in place
* Tampered seal removed
* Check service pressure
* Face valve outlet away from people
* Correct leaks
* Open the valve (slowly) to relieve excess pressure before bringing the cylinder to pt
* Open Slowly
Inspect Cylinder To Check For COO
| S14
## Footnote
sorry i removed the bolding, i was editing it and it got messed up.
43
What are **pipleline systems** used for?
* used to deliver non-flammable gases (O2, air, nitrous) to anesthetizing locations and other pt care areas*
| S15
44
What are the 3 main systems/pieces of pipeline system?
1. Central supply
2. Piping: recieved at 50psi
3. terminal units: maintaines approx 50 psi
| S15
45
Where are possible locations for the Central Supply?
* Outdoors in an enclosure
* Indoors in secure area
| S16
46
A Central Supply "bank" must contain gas for at least how many days?
* 2 days
| S16
47
Can the hospital have their 2 day bank of O2 supply in different locations?
* yes, can have primary and secondary bank
* may have reserve supply in secondary location
| S16
48
What are the 2 types of oxygen supply source?
1. Gaseous Supply
2. Liquid Supply
| S17
49
Differentiate between a gaseous and liquid oxygen supply source.
* Gaseous oxygen supply:
* contained in large G & H cylinders
* refilled on-site or transported
* Liquid oxygen supply:
* less expensive and more convenient to store
* refilled by supply trucks
* service can not be interrupted
| S17
50
What are the three classes of piping?
* **Main lines**: connect gas source to risers
* **Risers**: vertical pipes connecting main line with branch lines on each level of the facility
* **Branch**: sections supplying a room or group of rooms on one level of the facility
| S18
51
What is the purpose of Shut-off Valves?
* Permit specific areas of the piping system to be isolated for problems /maintenance.
* These are color coded.
| S19
52
* The area alarm system must be in at least how many places?
* The area alarm system must be labeled for what?
* What places will have the gas alarm system?
* Are area alarms color coded?
* 2 places
* Must be labeled for gas and area
* The affected unit, critical life support area, maintenance, engineering
* Yes, these are also color coded.
| S20
53
When does the area alarm trigger?
* The area alarm system will be triggered if pressure increases/decreases **20 %** from normal line pressure.
| S20
54
Area system alarm must be ____ AND ____.
* audible
* visible
| S20
55
What are terminal units?
* Point in piped gas distribution where user connects and disconnects by hose
| S21
56
What safety system does the terminal unit use?
* Diameter Index Safety System (DISS)
* DISS = Nipple and nut vary in bore and diameter
| S21
57
PISS is for?
DISS is for?
* PISS for cylinders
* DISS for wall units
| S21 lecture
58
* What allows convenient connection with one/both hands without tools to terminal units?
* Even though quick connected are convinient, what is the drawback to this?
* Quick Connectors
* Drawback: Quick Connectors leak more
| S22
59
Where are possible locations for Quick Connects?
* Wall
* Ceiling -mounted
* Ceiling column
| S23
60
What are the 2 functions of vaporizers?
* This is a device that changes a liquid anesthetic agents to a vapor
* adds a controlled amount of vapor to FGF in the breathing system
| S25
61
Modern volatile anesthetics exist in a liquid state below what temperature?
* 20C (68F)
| S26
62
In a closed container, VA molecules escape from a liquid to?
What is this dependent on?
* Vapor phase.
* dependent on characteristic of liquid and temperature.
| S26
63
Vapor molecules bombard container walls to create what?
Vapor Pressure
| S26
64
What is saturated vapor pressure (SVP)?
* When equilibrium is achieved b/w the liquid and vapor phases at a constant temperature from molecules hitting walls of container.
| S27
65
Saturated vapor pressure is dependent on what 2 things?
What is it independent of?
**Depedent on**:
* characterisitics of liquid
* temperature of liquid
**Independent**
* Of atmospheric pressure
| S27
66
* What is partial pressure?
* State Dalton's Law.
* **Partial pressure**: Part of the total pressure of any one gas in a mixture
* **Daltons Law**:
* Sum of Partial Pressure = Total Pressure
| S28
67
What is partial pressure dependent on?
* **Partial pressure depends on temperature**, not atmospheric pressure
| S28
68
Define volume percent
The concentration of a gas in a mixture expressed as a percentage
| S28
69
Volume percent is equal to
Partial Pressure / Total Pressure
| S28
70
**Halothane:**
* Trade name
* Vapor Pressure
* (Fluothane)
* 243 mmHg
| S29
71
**Isoflurane**:
* Trade name
* Vapor Pressure
* (Forane)
* 238 mmHg
| S29
72
**Desflurane**:
* Trade name
* Vapor Pressure
* Suprane
* 669 mmHg
| S29
73
**Sevoflurane**:
* Trade name
* Vapor Pressure
* Ultane
* 157 mmHg
| S29
74
The temperature at which vapor pressure equals to atmospheric pressure.
* Boiling point
| [idk where this FC is from]
75
The number of calories necessary to convert **1 gram of liquid into vapor** (or 1 mL of liquid to vapor).
* Heat of Vaporization
| S30
76
List the sequence of events that occur as carrier gas flows through the vaporizer.
* As carrier gas flows through the vaporizer, vapor molecules leave
* There will be an equilibrium shift, more molecules in a liquid state
* Liquid temperature drops, causing vapor pressure to drop
* Output of vapor will decrease
| S30
## Footnote
More heat will be needed to increase vapor output.
Vapor pressure is dependent on heat (temperature).
77
Number of calories required to raise the temperature of **1 g of a substance 1 degree C**
* Specific Heat
| S31
## Footnote
The higher the specific heat, the more heat required to raise the temp of the substance
78
Specific Heat of Water
* 1cal/g
* water is the standard.
| S31
## Footnote
The Standard
79
What do manufactures need to consider when choosing material for vaporizers and why?
* How much heat must be supplied.
* Material with higher specific heat minimizes temperature variation
| S31
80
The ‘speed’ at which heat flows through a substance
* Thermal Conductivity
| S32
81
The ____ the thermal conductivity, the better the substance conducts heat
The **higher** the thermal conductivity, the better the substance conducts heat
82
Why do we want metals with high thermal conductivity?
List exampls of metals with high thermal conductivity
* Metals with high thermal conductivity minimize temperature swings during vaporization.
* Examples: Copper and Aluminum
83
Modern vaporizers are ____-calibrated and have ____ bypass.
* Concentration
* variable
| S33
84
Where is the vaporizer located?
* Between flow meter and common gas outlet
| S33
85
What happens if the vaporizer is before the flow meter?
What happens if the vaporizer is after the common gas outlet?
* Carrier gas will be on the wrong side and will not be able to pick up adequate vapor molecules
* There will be less stability and flow of vapor molecules delivered to the patient
| S33 - Idk where this is from
86
Where should vaporizers not be located?
The vaporizer may not be past the **common gas outlet** because they are not calibrated for high flows of O2
| S33
87
# Variable bypass vaporizer
What regulates the concentration of the volatile in the vaporizer (variable bypass)?
* The concentration dial
| S34
88
How does a vaporizer dilute saturated vapor?
* Vaporizer dilutes saturated vapor by splitting gas flow.
* vaporizing chamber
* Bypass
* Ratio dependents on the size of the adjustable orifice
| S34
## Footnote
Higher splitting ratio means more flow will go through vaporizing chamber, higher anesthetic gas delivery.
89
What is splitting ratio dependent on?
* Ratio depends on the size of the adjustable orifice.
* Higher splitting ratio means more flow will go through vaporizing chamber, higher anesthetic gas delivery.
| S34
90
What are the two types of vaporizers?
* Flow-over (modern)
* Bubble through (older)
| S34
91
Why is desflurane heated in the vaporizer when its boiling point is at room temperature?
* There is a lot of variability at room temperature.
* Desflurane is heated to a precisely controlled temperature and stable vapor phase.
* The heated vapor is then “injected” into the fresh gas flow to deliver a precise anesthetic concentration.
| S35 [lecture?]
92
Modern vaporizers are automatic with tempetarure compensation. What does this mean?
* Modern vaporizers have a temperture sensing device. As the temperature increases and more vapor occurs, the vapor moves the temperature regulator.
* **Splitting ratio automatically changes as temperature changes**.
| S36
93
What factors can influence vaporizer output?
* **I**ncorrect agent in the vaporizer
* **P**umping Effect
* **F**GF Flow Rate
* **B**arometric Pressure
* **O**verfilling
* **T**ipping
* **L**eaks
* **E**ffects of Rebreathing
I Pump Fresh BOTLE
| S38-46
94
Why is placing the incorrect volatile agent in the vaporizer unlikely?
* Filling systems are agent-specific
* the monitor should detect 2 vapors if incorrectly filled.
| S38
95
How do you fix this issue if you somehow filled the wrong agent in the vaporizer?
* Vaporizer must be completely drained, and all liquid discarded
* Run FGF at 8-10 L/min until no vapor is detected
| S38
## Footnote
The monitor will detect 2 vapors if incrorect agent is added to the vaporizer
96
Since ____ and ____ have similar enough vapor pressures that you could use the same vaporizer, but filling would be difficult because they have different keys to fill with.
Halothane and Isoflurane
| S38 lecture
97
FGF flow rate can influence vapor ouput but its unlikely, why?
* Current variable-bypass vaporizer is constant at 250mL/min and 10L/min
| S39
98
What happens to the vaporizer output if the FGF flow rate is less than 250 ml/min?
* Output will be less than setting
* High density of volatile prevents upward movement of molecules
| S39
99
What happens to the vaporizer output if the FGF flow rate is greater than 15 L/min?
* Output will be less than setting
* Failure to saturate carrier gas because the carrier gas is too fast.
| S39
100
What are two common causes of the anesthesia machine's intermittent back pressure (pumping effect)?
* Positive Pressure Ventilation
* Oxygen Flush Valve
| S40
101
The pumping effect is more pronounced with:
* Low flow rates
* Low dial settings
* Low levels of liquid in the vaporizing chamber
| S40
## Footnote
These are things that could happen prior to uniderectional valve placement into the machine, tubing, and vaporizers.
102
What problem does the pumping effect have on vaporizer output?
* Inconsistency in maintaining alveolar pressure of anesthetic vapors
| S40 [lecture or ANDY not on slides]
## Footnote
Negate the pumping effect by maintain adequate flow rate and dial setting
103
What are some measures that help attenuate the pumping effect?
* Smaller vaporizing chambers
* Baffle systems
* Longer tube for the inlet of vaporizing chamber
* Addition of check valve
SLAB the pumping effect
| S41
104
What object in the anesthesia machine counters the pumping effect?
* Machine Outlet Check Valve
| S41 [idk where this is from]
105
Effects of rebreathing on vaporizers with high FGF
* Little exhaled gas rebreathed
* Inspired concentration = vaporizer setting
| S42
106
Effects of rebreathing on vaporizers with low FGF
* Significant rebreathing with low FGF.
* difference between vaporizer setting and inspired concentration.
| S42
107
In what scenario would we want rebreathing to occur? When would we want rebreathing to not occcur?
* We want rebreating during induction.
* Dont want rebreathign during emergence.
| S42 lecture.
108
* What are vaporizers calculated at?
* Vapor pressure is independent of?
* Calculated at sea level (760 mmHg)
* Independent of barometric pressure
| S43
109
Does an increase in altitude affect barometric pressure?
* This is contraversial
* Volume % of volatile increased significantly in vaporizers.
* Partial pressure of gasses chaneges lesser
* Anesthetic depth is partial pressuer in BRAIN
| S43
110
Why will an increase in altitude not affect the delivery of Isoflurane or Sevoflurane?
* Isoflurane and Sevoflurane are not pressurized. They operate as a function of atmospheric pressure.
* At sea level, atm = 760 mmHg. This pressure keeps molecules down in the liquid phase.
* So, in higher elevations, there will be less atmospheric pressure. Which means more molecules can escape as a gas.
* The decrease in atmospheric pressure and the increase in the volume percent of gas will equal the partial pressure of gas delivered at sea level.
* Refer to the math below or watch the YouTube link.
* https://www.youtube.com/watch?v=UgViWCNVgOA&ab_channel=CountBackwardsFrom10
| S43 [ANDY?]
111
What happens with tipping and how does it affect vaporizer output?
* Excessive liquid enters the bypass chamber
* Excessively high output
| S44
112
Tipping of the vaporizer can occur when what 3 thing are incorrectly done?
When incorrectly:
* removed
* transported
* replaced
| S44
113
What do you do when tipping occurs?
What is the purpose of a drager vaporizers?
* Manufacturers instructions
* Run on high flow and dry it up.
* Drager vaporizer have transport dials which isolates vaporizers and bypass chamber.
114
How does overfilling the vaporizer affect vapor output?
Liquid can enter the bypass chamber and excessive dose is then delivered to the patient.
| S45
115
What is in place to prevent overfilling over modern vaporizers?
* Designs to prevent overfilling by having an overflow hole
| S45
116
Vaporizer leaks can be caused by:
* Loose filler caps
* Drain valves
* Vaporizer/mounting bracket interface
Vaporizer Does Leak
| S46
117
What would be indicators of vaporizer leaks?
* Odor of gas
* Lower than expected inhaled concentration [Fi]
| S46
118
What will be the patient consequence of a vaporizer leak?
* Patient awareness
| S46
119
What are vaporizer safety standards?
* Filling levels displayed
* All control knobs counterclockwise
* Gas may not pass through more than 1 vaporizer
* Average concentrations +/- 20% of setting
* vaporizer interlock
* Output of vaporizer <0.05% in OFF
Fill All Gas Averages Out
| S47
120
What are the mounting standards of the vaporizer?
* Detachable
* standard on most machines
* Weight of vaporizer and "O" ring creates seal
* Locking lever on the back (front for cannisters)
* Easily removed and replaced (especially for MH)
| S48
121
What is the purpose of an interloack device?
* Prevents more than 1 vapor from being turns ON at a time.
| S49.
