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ANES 513B - Anesthesia Equipment > Midterm > Flashcards

Flashcards in Midterm Deck (71)
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1
Q

What is PSIg?

A

Pounds per square inch gauge

  • Diff b/t measured pressure and surrounding atmospheric pressure
  • Most gauges read 0 at atmospheric pressure
2
Q

What is PSIa?

A

Pounds per Square Inch Absolute

  • Based on reference point of 0 pressure for a perfect vacuum
  • PSIg + local atmospheric pressure (14.7 psi)
3
Q

What regulatory agency enforces medical gas purity?

A

FDA

4
Q

What agency regulates how gas cylinders are manufactured, labeled, filled, transported, stored & disposed of?

A

Dept. of Transportation (DOT)

5
Q

What are the 5 regulatory agencies associated with anesthesia gas?

A

FDA

DOT

United States Pharmacopoeia (USP)

Nat’l Fire Protection Agency (NFPA)

Compressed Gas Associated (CGA)

6
Q

What gases are used in anesthesia?

A

Oxygen (O2)

Air

Nitrous Oxide (N2O)

Helium (He)

Nitrogen (N2)

Nitric Oxide (NO)

Carbon Dioxide (CO2)

7
Q

What are the gases in the atmosphere (air)?

A
  • Nitrogen N2 - (28.01 - 78%)
  • Oxygen O2 (32 - 21%)
  • Argon Ar - (40 - 0.934%)
  • Carbon Dioxide CO2 - (44 - 0.031%)
  • Neon Ne - (20 - 0.0018)
  • Helium He - (4 - 0.000524%)
  • Krypton Kr - (84 - 0.000114)
  • Hydrogen H2 - (1.0079 - 0.00005)
  • Xenon Xe - (131 - 0.0000087)
8
Q

For what gases are cylinders the primary source of gas?

A

Helium

Heliox

CO2

9
Q

Are index pins located on the yoke or the cylinder?

A

The yoke

The cylinder contains the pin holes

10
Q

What are the steps to install an E cylinder?

A
  • Place cylinder gasket over the yoke inlet
  • Align holes in the cylinder valve with the pins on the yoke
  • Push the cylinder forward and into the yoke
  • Rotate the yoke arm upwards and over until thearm engages w/ the other side of the yoke
  • Turn the T-handle clockwise until it is tight and holds the cylinder firmly in place
  • To open cylinder, turn valve at least 1-2 turns counterclockwise using a cylinder wrench
11
Q

Where are the pipeline’s regulators located?

The cylinder’s regulators?

A
  • Pipeline: in the wall
  • Cylinder: in machine (behind yokes)
12
Q

What is the primary regulator?

A

The cylinder regulator (located in the machine behind the yoke)

13
Q

What is the pressure of the primary regulator?

A

45 psi

14
Q

What is the pressure of the pressure relief valve?

A

75 psi

15
Q

What is the E-cylinder capacity (L) and pressure (PSIg) of:

Air

CO2

He

HeO2

N2

N2O

O2

A

Air: 625 / 1900

CO2: 1590 / 838

He: 500 / 1600

HeO2: 500 / +

N2: 610 / 1900

N2O: 1590 / 745

O2: 660 / 2200

16
Q

What are the phases and US & Internat’l color codes for:

O2

Air

N2O

He

Heliox

CO2

N2

A

O2: Gas; Green / White

Air: Gas; Yellow / White & Black

N2O: Gas/Liquid; Blue / Blue

He: Gas; Brown / Brown

Heliox: Gas; Brown & Green / Brown & White

CO2: Gas/Liquid; Gray / Gray

N2: Gas; Black / Black

17
Q

How do you calculate total O2 consumption?

A

Total O2 consumption = Fresh Gas Flow (FGF) + Minute Ventilation (VE)

Ex:

FGF: 2 L/min

Tidal Vol: 0.7 L

RR: 10 bpm

VE = Tidal Vol. x RR = 0.7 L x 10 bpm = 7 L/min

Total O2 consumption: 2 L/min + 7 L/min = 9 L/min

18
Q

How do you calculate time left in an E-cylinder?

A

O2 Time Remaining = Residual / Consumption

Ex:

Residual: 225 L

Consumption: 9 L/min

Time remaining = 225 / 9 = 25 mins.

19
Q

What is pipeline pressure?

A

50 PSIg

20
Q

What are pipeline supply sources?

A

Oxygen

medical air

N2O (held in tanks)

21
Q

What is the cylinder’s index safety system?

What is the pipeline’s index safety system?

A

Cylinder: PISS (Pin Index Safety System)

Pipeline: DISS (Diameter Index Safety System)

22
Q

Where are the connectors for the DISS?

A

DISS connector is on the side going to the machine.

Quick connect or DISS (variable) is on the side going to the wall.

23
Q

What is the purpose of shutoff valves in the pipeline?

What are the types of shutoff valves?

A

Isolate specific piping system areas w/o turning off the entire system

Types: Manual (for a room)

Service (for an area)

24
Q

What is the master alarm system in a pipeline?

A
  • Monitors the central supply & distributiion system for all gases
  • Signals changes in pressure, supply changeovers & supply/reserve depletion
25
Q

What is the area (local) alarm system in a pipeline?

A
  • Monitors a specific area
  • Signals pressure changes 20% above/below normal operating pressure
26
Q

What are the functions of the anesthesia machine?

A
  • Receive gases from central supply system or pressurized cylinders
  • Control the flow of desired gases & reduce their pressure
  • Measure a precise amount of gases & load them with anesthetic vapors
  • Provide gas to patient for breathing
  • Provide monitoring & safety features
27
Q

What are the Datex-Ohmeda machines?

A

Excel

Aestiva

Aisys

Avance

28
Q

What are the Drager medical machines?

A

Apollo

Fabius GS

29
Q

What are the anesthesia machine standards from 1979, 1988, and 1999?

A
  • 1979 - ANSI Z79.8
    • Est. minimum standards for design, performance, safety
  • 1988 - ASTM F1161.88
    • Added pre-use checkout, calibrated vaporizers, O2 analyzer, prioritized alarms, alarms enabled by a master switch, airway pressure monitoring, volume monitoring, & capnography
  • 1999 - ASTM F1850-00
    • Addressed workstation of the future
30
Q

What are the high pressure components in the machine?

A

Hanger yoke (incl. filter and unidirectional valve)

Yoke block

Cylinder pressure gauge

Cylinder pressure regulators

31
Q

What are the intermediate pressure components in the machine?

A
  • The intermediate pressure system receives gases from the pipeline inlet or the pressure regulator (cylinder)
  • Intermediate pressure = 37-55 psi
  • This is pipeline pressure or the pressure after cylinder regulator
  • Components:
    • Pipeline inlets and pressure gauges
    • Gas power outlet
    • Master switch (pneumatic component)
    • O2 flush valve
    • O2 pressure failure device (fail-safe) & alarm
    • O2 and N2O 2nd stage pressure regulators
    • Flowmeter valves
32
Q

What is the function of the gas power outlet?

A

It is a gas source for the ventilator.

One or more gas power (auxiliary gas) outlets may be present on an anesthesia machine. It may serve as the source of driving gas for the anesthesia ventilator or to supply gas for a jet ventilator. Either oxygen or air may be used.

33
Q

What parts of the machine are still active when the machine is turned OFF?

A

O2 Flush

Gas Power Outlet

Electrical Outlets on the back of the machine

Battery recharging circuitry

Suction

Auxiliary O2

34
Q

What happens when the machine is in STANDBY?

A

In the STANDBY position:

  • No gas can flow to the patient
  • No electrical power goes to the Ventilator, Display, or CPU
  • O2 Flush is still available provided an oxygen supply is connected
  • Electrical outlets (if equipped) are still active
  • Battery will recharge
35
Q

What happens when the machine is in the ON position?

A

When the Switch is turned to the ON position ( l ) the following occur:

  • Oxygen is allowed to flow from the Main Output Manifold to the oxygen flowmeter
  • Air is allowed to flow from the Main Output Manifold to the Air flowmeter
  • Electricity flows to the components of the machine requiring electrical power, such as the ventilator, the display, & the CPU
36
Q

O2 Flush Valve

A
  • Directs a high unmetered flow (35-75 L/min) directly to the common gas outlet
  • Receives gas from the pipeline inlet or cylinder pressure regulator
  • Required by standards to be operable w/ 1 hand

Caution: pressure may be transmitted to other parts of the machine

37
Q

O2 Fail Safe Device / Alarm

A
  • Device that shuts off or proportionally decreases all gases except oxygen or alarms when oxygen pressure has fallen to a dangerous level (usually <30 psig)
  • Depends on pressure, not flow
  • 2 separate components, 2 sep. pressures
  • Relief valve is 75 psi
38
Q

How does the O2 Fail-Safe Device / Alarm work on the Datex-Ohmeda machines?

A
  • Alarm activated when O2 pressure < 30 psi
  • Gas flows stopped if O2 pressure <20 psi
  • If alarm starts, turn on cylinder b/c it goes off if you don’t have enough or have run out of O2
  • The Excel whistles when you turn it on b/c pressure is going from 0 to 30. It whistles when you turn it off b/c pressure is going from 30 to 0. Excel will turn off other gases (air, N2O) if O2 supply goes out
39
Q

How does the O2 Fail-Safe Device / Alarm work on the Drager?

A

N2O flow is decreased proportionally with O2 pressure

40
Q

When is the O2 Fail-Safe Device / Alarm activated?

A

When O2 pressure < 30 PSIg

41
Q

What is the secondary pressure regulator?

A
  • Reduce intermediate pressure to low pressure (from 50 –> 20 psiO2 and 38 psiN2O)
  • Decrease pressure fluctuations from the pipeline
42
Q

How does the flow control valve operate?

A
  • Turning the flow control knob counterclockwise moves the needle valve back & away from its seat to open a channel for the flow of gas into the flowtube.
  • Turning the knob clockwise closes the space between the needle valve & its seat.
  • O2 knob must be fluted and be as large or larger than other knobs. It must look and feel different than the other knobs
43
Q

What are the low pressure components in the machine?

A
  • Hypoxic guard / proportioning systems
  • Flowmeter tubes
  • Vaporizers
  • Check valves (if present)
  • Common gas outlet
  • Starts just after the flow control valves. Pressure is slightly above atmospheric
44
Q

What are the mechanical and pneumatic components of the hypoxic guard system?

A
  • Pneumatic:
    • Secondary Regulators
  • Mechanical:
    • Chain
  • The kick-in tab makes the clicking sound
  • The kick-in tab must engage with the stop tab to work properly
  • If you get above the 25% and turn down just N2O, you will disengage the stop screw
  • Only on the Excell machine
45
Q

What is the function of the common gas outlet?

A
  • Receive all gases and vapors from the machine
  • Deliver them to breathing system
  • This is a frequent place for circuit disconnection
46
Q

What was the first anesthesia delivery system?

A

Ether soaked rag

Done by Dr. Crawford Long March 30, 1842

47
Q

What is pipeline pressure? Cylinder Pressure?

A

Pipeline: 50 PSIg

Cylinder: 45 PSIg

48
Q

Which gases have the highest and lowest Blood/Gas ratio?

Blood/Brain ratio?

A

Blood/Gas:

  • Highest: Iso - 1.4
  • Lowest: Des - 0.42
  • The higher the #, the longer it takes to work

Blood/Brain:

  • Highest: Iso - 2.6
  • Lowest: Des - 1.3
  • The higher the #, the more potent
49
Q

What is the purpose of the gas reservoir bag?

A

Provides a place for gas to accumulate

50
Q

What is the purpose of the APL valve?

A

Provides ability to generate positive pressure in circuit

51
Q

What drives the bellows up and down?

A

Drive gas pushes bellows down

Expired gas from pt. pushes bellows up

52
Q

What are the types of CO2 absorbers?

What are the indications that they need to be changed?

A

Soda Lime and Baralyme

CO2 in inspired gases, color change and heat in canisters

53
Q

What is the most common type of scavenging?

A

Closed interface w/ active scavenging

54
Q

What are the required safety features in an anesthesia machine?

A

DISS

PISS

Low O2 pressure alarm

Hypoxic Guard

O2 failure safety device

O2 enters common manifold downstream to other gases

O2 concentration monitor and alarm

Automatically enabled essential alarms and monitors

Vaporizer interlock device

Capnography and anesth. gas measurement

O2 flush that doesn’t pass through vaporizers

Breathing circuit pressure monitor and alarm

Exhaled volume monitor

Pulse ox, EKG, and BP monitoring

Mechanical Ventilator

Scavenging system

55
Q

Step 1 of machine checkout

A

Verify backup ventilation equipment (AMBU bag) is available and functioning

AMBU bag is the only way of continuing positive pressure ventilation

56
Q

What are the steps and reasons of the machine checkout?

A
  1. Verify backup ventilation and equipment
    • AMBU bag is only way to deliver pos. press. vent.
  2. Check O2 cylinder supply
    • It is the backup supply
    • Also, so low O2 supply alarm alerts you
  3. Check central pipeline supplies (50 PSI)
    • Ensure adequate gas supply
  4. Check initial status of low press. system (everything OFF)
  5. Perform leak check of low pressure system
    • Creates vacuum to see if there are cracks in flowmeter tubes / vaporizers
  6. Turn on machine
  7. Test flowmeters
    • Ensure floats don’t get stuck
    • Hypoxic guard mechanism working
  8. Adjust and check scavenging system
    • Loose or improperly adjusted vacuum will release waste gases into OR
    • Broken neg. pressure valve will allow excessive vacuum and create subatmospheric press.
    • Broken pos. pressure valve will cause buildup of waste gases.
  9. Calibrate O2 monitor
    • Don’t want hypoxic gas mixture
    • Test alarm
  10. Check initial status of breathing system
    • Improperly attached circuit can cause vent. problems
    • Exhausted CO2 absorbent causes rebreathing
    • Absorbent change may cause circuit leak
  11. Perform breathing system leak check
    • Closing APL valve allows pressure to build up in circuit while using O2 flush creates high pressure
    • Gas will escape thru leak under high press.
    • You can measure amt of leak using FGF
  12. Test ventilation systems and unidirectional valves
    • High gas flows will hide a leak
    • Stuck insp. valve increases press. in machine
    • Stuck exp. valve increases press. in pt’s lungs
  13. Check capnometer
  14. Check final status of machine
57
Q

What is Peak Insp. Pressure (PIP) / Peak Airway Pressure (PAP)?

A

The pressure measured by the ventilator in the major airways.

Should be kept under 40 cmH2O

Strongly reflects airway resistance

58
Q

What is plateau pressure?

A

Positive press. applied to small airways and alveoli

Goal is to keep <30 cmH2O b/c excessive alveoli stretch is thought to be a cause of ventilator-induced lung injury

Usually 25% of insp. time

59
Q

What is peak flow?

A

Determines the rate of tidal volume delivery to the patient during mandatory volume control breaths

Affects I:E ratio adn peak pressure

60
Q

What is Volume Control Vent.?

What are the Independent and Dependent Variables?

A

Tidal volume is preset and the resultant airway pressure is a function of lung compliance and other factors

Independent Variables:

  • Tidal Vol.
  • RR
  • I:E ratio
  • FiO2
  • PEEP

Dependent Variables:

  • PIP
  • Plateau Press.
61
Q

What are the advantages and disadvantages of VCV?

A

Advantages:

  • Guaranteed min. vent.
  • May help lung compliance in certain surgeries

Disadvantages:

  • Pt. doesn’t trigger breath, but can see patient effort in capnogram
  • May need to reduce tidal vol. if you get high PIP/ PAP
62
Q

What is Pressure Control Ventilation?

What are the independent and dependent variables?

A

PAP is preset and the delivered tidal vol. is a product of lung compliance and other factors

Independent Variables:

  • Insp. Pressure
  • RR
  • I:E ratio
  • FiO2
  • PEEP

Dependent:

  • Tidal Vol.
63
Q

What are the advantages and disadvantages of PCV?

A

Advantages:

  • Reduced vent.-induced lung injury b/c able to limit PIP
  • Improved gas distribution b/c uses decelerating flow
  • More rapid improvement in lung compliance and oxygenation compared to VCV
  • Better method to use if you’re having problems ventilating the patient

Disadvantages:

  • Does not guarantee minute vent.
64
Q

PIP vs. Plateau Pressure in VCV and PCV

A

VCV:

  • PIP is determined from tidal volume set
  • Plateau Press. determined by applying an inspir. hold

PCV:

  • PIP usually the same as Plateau Press. b/c of how breath is delivered
  • There is an inherent inspir. pause
65
Q

What is Pressure Support Ventilation?

What are the independent and dependent variables?

A

Spontaneous vent. mode that provides constant pressure once patient inspir. effort is sensed.

Independent:

  • Support Press.
  • Inspir. Time
  • Flow Trigger
  • FiO2
  • PEEP

Dependent:

  • Tidal Vol.
  • RR
66
Q

What are the advantages and disadvantages of PSV?

A

Advantages:

  • Able to have patient breathe spontaneously and not fight the ventilator
  • Able to augment tidal vol.
  • Able to adjust ETCO2 w/ support press.

Disadvantages:

  • Requires pt. to be breathing spontaneously
  • Can’t control RR
67
Q

What is SIMV?

What are the independent and dependent variables?

A

Breaths given at preset time intervals.

Pt. can breathe spontaneously b/t the ventilator breaths

Ventilator will not give a breath if the pt. inspires at the same instant

Independent Variables:

  • Tidal Vol.
  • RR
  • I:E ratio
  • FiO2
  • Pressure Support Level
  • PEEP

Dependent Variables

  • PIP
  • Plateau Press.
68
Q

What are the advantages and disadvantages of SIMV?

A

Advantages:

  • Can be used as a way to start building up CO2
  • Back up mode for PSV

Disadvantages

  • May confuse pt’s brain b/c not physiological
69
Q

Ventilator Settings for:

Tidal Vol.

RR

VE

A

Tidal Volume:

10-15 mL/kg (adults)

6-10 mL/kg (infants, children, COPD)

RR: 10 initial

Minute Ventilation: Tidal Vol x RR

Men: 4 x BSA

Women: 3.5 x BSA

70
Q

In what ventilator setting can you use Inspiratory Pause?

A

VCV

Takes time from inspiration

71
Q

What is auto-PEEP and what are the indications?

A

Air trapping in the lungs b/c of insufficient exhalation time

Signs:

Non-zero end expiratory pressure

Increasing PIP/PAP