Anesthesia Machine Overview

Question 1

What do the components of the anesthesia workstation function to do?

Answer 1

deliver known concentrations of inhaled anesthetics to the patient

Question 2

What does the anesthesia work station consist of?

Answer 2

anesthesia machine, vaporizers, ventilator, breathing system, scavenging system, respiratory and physiological monitors

Question 3

What are the benefits and disadvantages of having everything in one workstation?

Answer 3

benefits: reduces chances of disconnections
disadvantages: variety of machines; learning curve for each one

Question 4

What is something you have to do with a computerized AW?

Answer 4

power it down q24h

Question 5

What is the common gas outlet?

Answer 5

where the AW provides delivery of medical gases and vapors of volatile anesthetics

Question 6

What is the common place for disconnect at the AW? Where do gases mix prior to going to the patient?

Answer 6

common gas outlet

Question 7

After the common gas outlet, where do the gases go?

Answer 7

they enter the anesthetic breathing system

Question 8

How are the gases delivered to the patient?

Answer 8

via spontaneous or mechanical ventilation

Question 9

How are exhaled gases removed?

Answer 9

scavenger; from the breathing system

Question 10

What groups set the standards for AWs? What standards do they specifically set?

Answer 10

American Society for Testing and Materials (ASTM)= year 2000 and newer
American National Standards Institute (ANSI)= earlier than 2000

Question 11

What are 5 pathways for O2 in the anesthesia machine?

Answer 11

1. flow to fresh gas flowmeters
2. powers the O2 flush valve
3. activates the failsafe mechanisms
4. activates the O2 low pressure alarm
5. compresses the bellows of the vent

Question 12

The pneumatic system is a _________pressure system. It has 3 levels, what are they?

Answer 12

air
high
intermediate
low

Question 13

What does the high pressure system do?

Answer 13

reduces pressure from cylinder pressure to pressure suitable for use in the machine

Question 14

What is the DISS? What does it provide?

Answer 14

Diameter Index Safety System; provides noninterchangable connections for the medical gas lines

Question 15

What does the DISS consist of? Why is this important?

Answer 15

body, nipple and nut connection; only properly mated parts will fit together and allow the threads to engage

Question 16

Is a DISS required or optional part of the anesthesia workstation?

Answer 16

required

Question 17

What is involved in the intermediate pressure system?

Answer 17

pipeline sources of O2, N2O, air
pressure regulators (2nd stage)
Oxygen pressure failure device
flow meter control valves
flush valve

Question 18

What is part of the low pressure system?

Answer 18

flow meter tubes
hypoxia prevention safety device
unidirectional valves (outlet check valve)
pressure relief devices
common gas outlet
vaporizers/manifold

Question 19

What is the pressure level of the low pressure system?

Answer 19

slightly higher than atmospheric

Question 20

What is the O2 pressure sensor shut off valve?

Answer 20

safety valve downstream from the N2O supply source

Question 21

What is the purpose of having the O2 pressure sensor shut off valve?

Answer 21

shuts off N2O or proportionally decreases the supply of N2O allowed into the machine if O2 supply pressure decreases to a predetermined threshold value (ie 25psi)

Question 22

What are 2 different types of O2 pressure sensor shut off valves?

Answer 22

threshold: either on or off

proportioning type: OFPD responds proportionally to changes in O2 supply pressure

Question 23

What types of cylinders are typically used for the AW?

Answer 23

E

Question 24

What system allows only the correct tank to be attached to the correct hose on the AW? How does it work?

Answer 24

PISS: Pin Index Safety System

holes on the tank only allow specifically placed pins to fit in; #ed from left to right 1 to 6

Question 25

What are the PISS settings for O2, N2O and air?

Answer 25

O2: 2 & 5 N2O: 3 & 5 air: 1 & 5

Question 26

When is an E cylinder of oxygen considered full?

Answer 26

at 2000psi or approximately 625-650 liters of O2

Question 27

What happens to the pressure of the O2 tank as O2 is used up?

Answer 27

pressure falls in proportion to amount of O2 left in tank

Question 28

If a tank starts out at 2000psi and 625L of O2, then drops to 1000psi, how much O2 is left?

Answer 28

312.5L

Question 29

If your O2 tank is half full and you are running O2 at 2L/min, how many hours do you have left before the O2 runs out?

Answer 29

2.6 hours (156minutes)

Question 30

What does the number on the O2 pressure gauge on the cylinder reflect?

Answer 30

the volume of O2 stored as a gas

Question 31

What is the volume of O2 in a cylinder if the psi is 2200, 1100, 550, 225, and O?

Answer 31

``` 2200psi=625L 1100psi=312.5L 550psi=156.25 225psi=78L 0psi=0L ```

Question 32

What is the psi of a full N2O tank?

Answer 32

745psi

Question 33

What does a pressure regulator do?

Answer 33

reduces the pressure to a constant 45psi

Question 34

What is a type of pressure regulator not in all machines?

Answer 34

second stage

Question 35

What does a second stage regulator do? Where is it found?

Answer 35

reduces the pressure even more (14psi for O2, 26psi for N2O) found downstream from pressure regulator

Question 36

What is the purpose of a flow meter?

Answer 36

to measure gas flow to the common gas outlet

Question 37

What are 2 types of flow meters?

Answer 37

Thorpe tubes; electronic flow sensors

Question 38

What are some safety features of flow meters?

Answer 38

color coded; O2 flow knob is distinct; location of O2 flow knob

Question 39

What are the color codes of the gases?

Answer 39

O2=green N2O=blue air=yellow

Question 40

How is the O2 flow knob distinct?

Answer 40

distinctively fluted; projects beyond control knobs of the other gases; larger in diameter

Question 41

Why is the O2 flow meter positioned downstream?

Answer 41

downstream from N2O prevents hypoxic mxture if leak is present: NOT FAILSAFE

Question 42

What can happen if there is a leak in the O2 flow meter?

Answer 42

hypoxic mixture

Question 43

What is the flow rate of the O2 flush?

Answer 43

35-75L/min

Question 44

Where does the O2 flush go to?

Answer 44

directly to machine outlet-->patient circuit

Question 45

What is a potential adverse effect of using the O2 flush?

Answer 45

potential for barotrauma

Question 46

What is the only reasonable use for using the O2 flush?

Answer 46

aid in machine check; fill bellows on expiratory phase of respiration

Question 47

What is a safer way to fill the bellows?

Answer 47

turn up O2 flow meter

Question 48

What does using the O2 flush not replace?

Answer 48

a good mask fit

Question 49

When is the anesthesia machine checked?

Answer 49

1. complete and thorough daily check | 2. circuit check before each new case

Question 50

What is the best monitor at your disposal?

Answer 50

VIGILANCE

Question 51

What are monitors effective in doing?

Answer 51

detecting problems with or adequacy of ventilation and oxygenation

Question 52

What are common monitors you will see?

Answer 52

EKG, SBP, temp, O2 sats, CO2, anesthetic gases and vapors, alarm systems

Question 53

What monitor is the best for detecting a disconnect? What else may show this?

Answer 53

ETCO2 | low pressure alarms

Question 54

What is the most important monitor on the machine? What does it do?

Answer 54

Oxygen analyzer | detects if machine is getting correct FIO2

Question 55

What do you want to calibrate the O2 analyzer to?

Answer 55

21% O2; room air

Question 56

What monitor provides ongoing monitoring of exchange?

Answer 56

SpO2

Question 57

What are you checking in a machine check?

Answer 57

gas line connections; vent check; flow meter controls; vaporizer levels; O2 analyzer; low pressure circuit leak check; circle system test; work station self tests

Question 58

What is the only monitor that detects problems downstream from the flow control valves?

Answer 58

oxygen analyzer

Question 59

What is the process of checking the O2 analyzer?

Answer 59

expose O2 sensor to room air for given amount of time

Question 60

What is the purpose of checking the low pressure circuit test?

Answer 60

checks the integrity of the machine from flow control valves to the common gas outlet

Question 61

What parts of the machine are most vulnerable to breakage?

Answer 61

components in the low pressure circuit

Question 62

Is there 1 specific way to check the low pressure circuit?

Answer 62

no; differs w/ machine depending on whether or not the machine has a check valve

Question 63

For a 1993 FDA negative pressure leak test, what switches must be turned off or on?

Answer 63

machine master switch, flow control valves, and vaporizers: all must be in OFF position

Question 64

What is the suction bulb attached to for a leak test?

Answer 64

common gas outlet

Question 65

Why is the suction bulb squeezed several times in a leak test? How do you know if the machine is leak free?

Answer 65

squeeze until it is fully collapsed: this creates a vacuum in the low pressure circuit bulb remains collapsed for at least 10 seconds

Question 66

What is the purpose of a circle system check?

Answer 66

evaluate the integrity of the circle breathing system

Question 67

Where does the circle breathing system extend from?

Answer 67

the common gas outlet to the Y piece

Question 68

How do you perform a leak test of the circle system?

Answer 68

occlude the Y piece, close off APL valve, pressurized the circuit to 30 cm H2O using the O2 flush valve

Question 69

What are you looking for on the leak test of the circle system?

Answer 69

sustained positive pressure reading on the airway pressure gauge

Question 70

What does a leak test of the circle system not test?

Answer 70

the integrity of unidirectional valves

Question 71

What does test the unidirectional valves?

Answer 71

flow test

Question 72

How do you perform a flow test of the circle system?

Answer 72

attach breathing bag to Y piece, turn on ventilator and assess integrity of unidirectional valves

Question 73

What will dilute the anesthetic if you use it on the patient?

Answer 73

O2 flush valve

Question 74

What prevents backflow of gas?

Answer 74

outflow check valve

Question 75

What is the main component of the high pressure system?

Answer 75

tanks

Question 76

What is the psi that the gas in the tanks is reduced to?

Answer 76

45psi

Question 77

What is the psi that the gas from the pipeline is reduced to?

Answer 77

50psi

Question 78

What is the main component of the intermediate pressure system?

Answer 78

pipeline

Question 79

What is the symbol for the Oxygen flush valve?

Answer 79

O2+

Question 80

The flow meters are part of the _________pressure system but the knobs are part of the __________ pressure system.

Answer 80

low | intermediate

Question 81

Describe the hypoxic prevention device.

Answer 81

oxygen is always downstream from N2O (O2 is closest to vaporizer) this way if there is a crack in the system, O2 will still be pumped to patient If you turn on N2O before O2, O2 will turn up to 30% before N2O turns on Also, if you turn O2 down, N2O will decrease as well

Question 82

If the O2 pressure shut off alarm goes off, what will the workstation do? What will it not do?

Answer 82

it will turn off N2O and air and only give patient O2 | It won't turn off the anesthetic

Question 83

What does the O2 pressure shut off valve not respond to?

Answer 83

FiO2

Question 84

If the O2 fail safe alarm goes off, what should you do?

Answer 84

disconnect the pipeline and use the cylinder

Question 85

If your patient is on O2 and you want to decrease your FiO2 from 100% at 10L/min to 50% @ 10L/min, how do you adjust your gases if you are using O2 and N2O?

Answer 85

give 5L/min of both O2 and N2O