Exam 3 Compressed Gases and Vaporizers (Mix of Grayson/Cooper) (7/1/24) Flashcards

1
Q

Which gasses are non-liquefied gasses?

A
  • Oxygen
  • Nitrogen
  • Helium
  • Air
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2
Q

Which gasses are liquefied?

A
  • Nitrous Oxide
  • Carbon Dioxide
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3
Q

At what pressures does a liquefiable gas become liquefied?

A

25 - 1500 psi

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4
Q

What aspect of the goverment regulates gas purity?

A

FDA

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5
Q

What aspect of the goverment regulates marking, labeling, storage, & handling?

A

DOT

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6
Q

What aspect of the goverment regulates employee safety?

A

OSHA

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7
Q

The base of a gas tank has what shape?

A

Flat or Concave

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8
Q

What material are gas tank valves made from?

A

Bronze or brass

These allow refilling and discharge of gas

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9
Q

What should be attached to every single gas cylinder?

A

Handle

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10
Q

What vents cylinder contents to the atmosphere if the pressure increases to a dangerous level?

A

Pressure relief device

disc or plug

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11
Q

What is the PIS system?

A

Pin Index Safety System = Holes and cylinder valve that only work with the correct pins on the yoke/pressure regulator.

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12
Q

What is the smallest cylinder size?
What is the biggest?
What cylinder size is used for anesthesia machines?

A

A = smallest
H = Largest
E = Anesthesia
D = Transport

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13
Q

What is the approximate PSI from the cylinder supplying gas to the machine?

A

45 psi

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14
Q

Why must the gas cylinders on the back of our machines always remain closed?

A

As a safety mechanism so that if the wall pressure fails, we will have an audible alarm to alert us that we are switching from wall pressure to tank pressure and we only have minutes of oxygen left.

(Kane talked about this on slide 8)

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15
Q

What is the pressure-volume relationship of a non-liquefied stored gas?

A

As pressure decreases, so does volume

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16
Q

Approximate psi of full non-liquified gases in a cylinder:
What about the volume in a full tank?

A

1900 or 2000 psi (Range)
Approximately 600 L

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17
Q

What is the relationship between pressure and volume for a liquefied gas?

A
  • Pressure dependent on vapor pressure so pressure is not an indicator of remaining volume.
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18
Q

For a tank of nitrous, almost all of the time the tank psi will read ___. Except for when the tank is almost completely empty, when it will read ___.

A

745 psi

350 psi

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19
Q

What are some DOT regulations for what has to be placed on a gas tank?

A
  • Service pressure
  • Test Date
  • Caution label (Diamond shape)
  • Manufacturer info
  • Expiration date
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20
Q

How often should the gas cylinder valves, regulators, and gauges be lubricated?

A

Trick question. Never.

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21
Q

A gas cylinder should never be exposed to temperatures above _____.

A

54° C (130° F)

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22
Q

What are standards for storage rooms for gas cylinders?

A
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23
Q

Which of the following statements are true regarding checks/safety standards prior to use of oxygen cylinders?
(Select 3)

A. Open the tank valve quickly to ensure rapid flow.
B. Open the valve after bringing the cylinder to the patient.
C. Inspect the pin index holes, label and regulator prior to use.
D. Face the valve outlet toward the patient/operating field.
E. Ensure there are at least 2 washers in place.
F. Remove the tamper seal.
G. Check the service pressure.

A

C. Inspect the pin index holes, label and regulator prior to use.
F. Remove the tamper seal.
G. Check the service pressure.

Rationale: We want to open the tank slowly. We are supposed to open the valve before bringing the cylinder to the patient. We want to face the valve outlet away from people. There should only be one washer in place.

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24
Q

What is used to deliver non-flammable gasses (O₂ , N₂O, medical air) to anesthetizing locations and other patient care areas?

A

Pipeline systems

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25
Q

What are the 3 components to the “Pipeline Systems”?

A
  1. Central Supply
  2. Piping (Received at 50 psi)
  3. Terminal units (approx. 50 psi)
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26
Q

How many days of oxygen should a central supply for a hospital “bank” for emergencies?

A

2 days worth

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27
Q

What are the benefits of a liquid supply/storage of gas?

A
  • less expensive & convenient to store
  • refilled via supply trucks
  • no interruption to service
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28
Q

What are the three classes of piping?

A
  • Main - connect gas source to risers
  • Risers - vertical pipes connecting mainline w/ branch lines on each level of hospital.
  • Branch - section supplying rooms on one level of facility.
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29
Q

What permits specific areas of a piping system to be isolated for problems and maintenance?

A

Shut-off Valves

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30
Q

Area alarm systems are found in _______ areas.

A

critical life support

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31
Q

Should the area alarm systems alarm in the following circumstances?

Normal Line Pressure: 45 psi –> New Pressure –> 61 psi
Normal Line Pressure: 50 psi –> New Pressure –> 42 psi
Normal Line Pressure: 60 psi –> New Pressure –> 46 psi

A

Normal Line Pressure: 45 psi –> New Pressure –> 61 psi
* YES ( > 20% Change)

Normal Line Pressure: 50 psi –> New Pressure –> 42 psi
* NO (< 20% Change)

Normal Line Pressure: 60 psi –> New Pressure –> 46 psi
* YES (> 20% Change)

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32
Q

Where are the places where the area alarm is supposed to sound off at?

A
  • Maintenance
  • Engineering
  • Affected unit

AT LEAST 2 PLACES!

33
Q

What connection system is used in terminal units?

A

DISS (Diameter Index Safety System)

“quick connects”

34
Q

What is the point in a piped gas distribution where the user connects and disconnects by hose?

A

Terminal units

35
Q

What are the advantages and disadvantages of quick connectors?

A
  • Convenient and allow connection w/o tools
  • Leak more
36
Q

Modern volatile anesthetics exist in a liquid state below ____°C.

A

20°C

68°F

37
Q

Is vapor pressure dependent on atmospheric pressure?

A

No, Vapor pressure is independent of atmospheric pressure.

38
Q

Which law corresponds to the sum of partial pressures?

A

Dalton’s Law

Partial pressures are dependent on temperature

39
Q

How do we calculate Volume’s Percent?

A

Partial pressure / Total pressure

40
Q

What is the term for when the gas phase above a liquid contains all the vapor it can hold?

A

Saturation.

Pressure exerted by this vapor is SVP (Saturated Vapor Pressure).

41
Q

What is the trade name and vapor pressure of halothane?

A

Fluothane

243 mmHg

42
Q

What is the trade name and vapor pressure of Isoflurane?

A

Forane

238 mmHg

43
Q

What is the trade name and vapor pressure of Desflurane?

A

Suprane

669 mmHg

44
Q

What is the trade name and vapor pressure of Sevoflurane?

A

Ultane

157 mmHg

45
Q

________ ______ is the temperature at which vapor pressure equals atmospheric pressure.

A

Boiling point

46
Q

_______ ___ _________ is the number of calories necessary to convert 1g of anesthetic liquid into vapor.

A

Heat of vaporization

47
Q

______ ____ is the number of calories required to raise the temperature of 1g of a substance by 1°C.

A

Specific Heat

48
Q

Materials with a _____ specific heat will minimize temperature variations.

A

higher

49
Q

This term describes the “speed” at which heat flows through a substance.

A

Thermal conductivity

50
Q

True or False:
The lower the thermal conductivity, the worse the substance conducts heat

A

TRUE

51
Q

What will metals with a high thermal conductivity do?
Which metals are examples of this?

A
  • ↑ thermal conductivity = minimize temperature swings w/ vaporization
  • Copper & aluminum
52
Q

What does it mean when we say a vaporizer is “concentration-calibrated, variable bypass”?

A
  • Concentration-calibrated = calibrated to give via a concentration (ex. 6% desflurane, won’t give in mg of des)
  • Variable bypass refers to the wicking chamber
53
Q

Vaporizers cannot be past the _________ ________ _______.

Specifically where should they be located?

A

Common gas outlet.
Vaporizers are not calibrated for the high flows of the oxygen flush button

Between the flow meter and the common gas outlet

54
Q

What type of vaporizer is depicted below?

A

Old style “bubble-through” vaporizer

55
Q

What type of vaporizer is depicted below?

A

New style “Flow-over” vaporizer

56
Q

Aside from manually changing the splitting ratio to deliver more or less gas, what is another way in which the splitting ratio can change?

A

Automatic Temperature Compensation:
* Splitting ratio changes as temperature changes

57
Q

What would be the fix if a vaporizer were to run the wrong gas through it?

A
  • Completely drain & discard liquid
  • FGF until no more vapor is detected
58
Q

How do we avoid filling a system with an incorrect anesthetic agent?

A

Filling systems should be agent specifc (Keys/color codes are different)

59
Q

Super-crazy scenario that will definitely never happen but stay with me

A patient comes into the OR and has a crazy allergy to iso, sevo and des but the surgeon says we ABSOLUTELY HAVE to use gas for this case and he knows we keep bottles of halothane on hand. But we do not have an actual halothane vaporizer… What can we do to keep Dr. Douchebag happy and safely administer gas to the patient?

A

Technically, because both isoflurane and halothane have very similar vapor pressures, you could put the halothane into the isoflurane vaporizer cannister.

Still a bad idea but Kane mentioned it is possible.

60
Q

What occurs with vaporizers at high flow (>15L/min) rates?

A

Failure to saturate carrier gasses

61
Q

What occurs with vaporizers at low flow (<250mL/min) rates?

A

High density of VAA prevents movement onward through the anesthesia machine (gas fails to saturate).

62
Q

What are the causes of intermittent back pressure (pumping effect) on vaporizers?

A
  • Positive pressure ventilation
  • Oxygen flush valve use
63
Q

What factors make a pumping effect in vaporizers more pronounced?

A
  • Low flow rates
  • Low dial settings
  • Low levels of liquid in the vaporizing chamber
64
Q

Whats done to anesthesia machines to decrease the occurence of the pumping effect?

A
  • Smaller vaporizing chambers
  • Baffle systems
  • Longer tube for the inlet of vaporizing chamber
  • Addition of check valve
65
Q

T/F. A higher FGF results in more exhaled gas being rebreathed.

A

False. ↑ FGF = ↓ rebreathing

66
Q

What two factors would cause significant rebreathing?

A
  • ↓ FGF
  • ↑ V̇T
67
Q

Technically, when may be a good time for our patient to experience some rebreathing?

A

During induction = rebreaths some of the volatile

68
Q

Vapor pressure is dependent/independent of barometric pressure.

A

Independent

69
Q

What occurs with anesthetic depth at high altitude?
Why is this?

A

No changes vs sea level. Volume % may change but partial pressures and solubility to brain won’t change.

70
Q

What could cause excessively high vaporizer output?

A

Tipping

71
Q

How do modern vaporizer’s prevent overfilling?

A

Overflow holes

72
Q

What occurs when overfilling happens?

A

Liquid enters bypass chamber → excessive dose delivered to patient.

73
Q

What causes VAA leaks?

A
  • Loose filler caps
  • Drain valves
  • Faulty vaporizer mounting bracket interface
74
Q

How would a leak in the vaporizer present?

A
  • Gas odor
  • Lower than expected inhaled concentration
75
Q

What occurs to the patient with vaporizer leaks?

A

Patient awareness

76
Q

A vaporizer standard average concentrations must be +/- ___% of setting.

A

20

77
Q

What is the output of a vaporizer when turned off?

A

< 0.05%

78
Q

What prevents more than one vaporizer from being turned on at a time?

A

Interlock Device