Anesthesia Machine Flashcards
(83 cards)
1
Q
State purpose of Hanger Yoke Assembly
A
- Ensures gas tight seal
- orients cylinder (PISS)
2
Q
Purpose of PISS
A
prevents misconnection of a cylinder to the wrong yoke
3
Q
Purpose of a Hanger Yoke check valve
A
- free floating valve (opens & closes w/ press)
- prevents retrograde gas flow
- allow change of cylinders during use
- minimize gas leaks to atmosphere if a yoke is empty
- minimize trans-filling of gases
4
Q
Purpose of minimizing trans-filling of gases
A
- prevents a full cylinder from emptying into an empty cylinder
- prevents wall O2 from entering an empty cylinder
5
Q
How is cylinder pressure measured?
A
Bourdon press gauge
6
Q
What is the PSI of O2?
A
2000-2200
7
Q
What is the PSI of N2O
A
750 PSI
8
Q
Purpose of cylinder press regulator
A
converts cylinder press to a constant press of 45 PSIG downstream of regulator
9
Q
N2O will read what PSIG?
A
It will read 745 PSIG until all the liquid in the cylinder has vaporized to gas
10
Q
What can be assumed with a N2O reading < 745 PSIG
A
That 75% of N2O cylinder gas has been exhausted
11
Q
Can the volume of N2O cylinder be determined based on the PSIG?
A
No
12
Q
What happens if a pressurized gas falls below a critical value (critical temp)
A
The molecules will get close together and form liquid
13
Q
What happens if a pressurized gas rises above the critical value called critical temp
A
The molexules will not get close enough and stay in a gaseous state
14
Q
What the crtical temp of O2 an N2O
A
O2 -119 C
N2O 39.5 C
15
Q
Purpose of DOT
A
estabiling criteri for design, labeling and storage of tanks
16
Q
Who issus standards to protect the health and safety of workers?
A
NIOSH & OSHA
17
Q
PSIG of O2
A
2200
18
Q
PSIG of N2O
A
745
19
Q
PSIG of Air
A
1900
20
Q
What is the sequence of the O2 flowmeter tube?
A
O2 is always to the right or downstream of all other gases and closest to the manifold outlet
21
Q
Why are flow valves linked mechanically or pneumtically?
A
- So O2 cannot be set below 25%
- ensures adequate % of O2 delivery
- O2 flow control spindle is connected to the N2O spindle
22
Q
Result of O2 spindle being connected to N2O spindle
A
- If you increase N2O flow, O2 flow will increase
- if you increase O2 flow, N2O will not increase
- If you decrease N2O flow, O2 fow wll not decrease
23
Q
What is heat of vaporization?
A
The # of calories required at a specific temp to convert 1G of liquid to vapor
24
Q
Why does relief gas valve exist?
A
It will open if gas flow exceeds that which is required for delivery of gas concentration on dial
25
Why does the temp compensating bypass valve exist?
It will open and allow gas to bypass vaporizer chamber
26
The vaporizer should not be tilted beyond how many degrees and why?
45 degrees. If it does the vaporizer must be drained and dried or can deliver uncertain % of anesthetic agent
27
The vaporizer interlock ensures that...
- Only 1 vaporizer is turned on
- Gas enters only the one which is on
- Trace vapor output is minimized when the vaporizer is off
- vaporizers are locked into the gas circuit , ensuring they are seated correctly
28
Purpose of vaporizer interlock mechanism
Safety mechanism that allows only one vaporizer at a time to be opened
29
What happens if the wrong agent were placed in a vaporizer? and what must you do if this occurs?
It will deliver an unknown concentration of agent to pt
| -Must empty, flush w/ 100% O2 and dry
30
What is HLH?
Higher VP agent in lower VP vaporizer chamber
| - higher concentration will be delivered
31
What is LHL?
Lower VP agent in higher VP vaporizer chamber
| -lower concentration delivered
32
What is the function of any breathing system?
To deliver O2 an anesthetic gases and eliminate CO2
33
How is CO2 washout accomplished?
Either with adequate FGF or by soda lime absorption
34
Purpose of APL valve (pop-off valve)
Limits amt of pressure inside the pts lungs during manual ventilation
- if pressure reaches the setting of the APL knob, the valve opens and allows excess gas to escape to the scavenging system
35
What direction would you turn the APL valve to increase or decrease the pressure?
Turning knob to right (closing) increases the pressure
| - Turning knob to left (opening) decreases the pressure
36
What is th mesh size of soda lime?
4-8
37
What is the mesh size of baralyme?
4-8
38
What is the method of hardness of soda lime?
silica added
| -minimize dust formation
39
What is the method of hardness of baralyme?
Bound water of crytallization
40
What are the contents of soda lime?
NaOH 4%
KOH 1%
CaOH 95%
41
What are the contents of baralyme?
CaOH 80%
| BaOH 20%
42
What is the absorptive capacity (L of CO2/100G granules) of soda lime?
14-23
43
What is the absorptive capacity (L of CO2/100G granules) of baralyme?
9-18
44
Characteristics of AMSORB
- CaOH
- CaCL
- doesn't form compound A or carbon monoxide
45
What are the final products of CO2 neutralization?
Carbonates + water + heat
| CaCO3+2 H2O + Heat
46
List factors increasing compound A
- total gas flow rates below 1L/min
- use of baralyme rather than soda lime
- high absorbent of sevoflurane
- drying of the CO2 absorbent
- length of anesthetic
47
Which gases produce carbon monoxide?
Desflurane>Enflurane>Isoflurane with absorbents produces carbon monoxide
-high concentrations w/ absorber that haven't been used for 24 hrs or more
48
factors increasing Carbon monoxide
- use of baralyme rather soda than soda lime
- higher temps in absorber
- dry absorbent
- higher anesthetic concentrations
- increasing length of time
49
Purpose of selector valve
Allows the selecton of manual or mechanical ventilation
| -isolates APL valve from rest of system
50
what is TV?`
volume of gas entering or leaving the pt during inspiratory or expiratory phase time
51
what is MV?
sum of tidal volumes in one minute
52
What is ventilatory frequency?
number of respiratory cycles per minute
53
what is inspiratory pause time
period from the end of inspiratory flow to the start of expiratory flow
54
what is inspiratory phase time?
period of time b/w the start of inspiratory flow and the beginning of expiratory flow or it is the sum of the inspiratory flow time and the inspiratory pause time
55
what is the expiratory pause time ?
interval from the end of expiratory flow to the start of inspiratory flow
56
What is the expiratory phase tijme?
time b/w the start of expiratory flow and the start of inspiratory flow or it is the sum of the expiratory flowtime and the expiratory pause time
57
what is the inspiratory and expiratory phase time ratio?
I:E ratio is the ratio of inspiratory phase time to expiratory phase time
58
what is the inspiratory flow rate?
volume of gas per unit time that passes from th pt connection of the breathing system to the pt
59
what is the expiratory flow rate?
volume of gas per unit time returned from the pt during the expiratory phase
60
What is resistance?
pressure diff per unit flow across the airway
| -it usally increases as flow increases
61
what is compliance?
ratio of a change in volume to a change in pressure
62
Purpose of bellows
separates breathing system gases from driving gas
63
Describe Ascending (standing) bellows
- most commonly used
| - rise (fill) during expiration and fall (empty) during inspiration
64
Describe Descendin (hanging) bellows
- unrecognizable pt disconnection
| - bellows will continue to fill and empty even when the pt is disconnected from the vent
65
Name two sets of gases in the ventilator
- Driving gas - outside the bellows
| - Patient gas - inside the bellow
66
Normal range of tidal volume
10-15 ml/kg (dependingon th ETCO2 and PIP)
67
Describe I:E ratio
uses 1 for the inhalation time and an appropriate # expressing the relative length of exhalation time
68
Purpose of scavenging systems
- removes gasses vented from the breathing system
| - minimizes venting of waste gases into the OR
69
NIOSH recommends limiting room concentration of gases to be?
- N2O - 25 ppm
- Halogenated agents - 2 ppm
- Halogenated agents with N2O - 0.5 ppm
70
List the pressure systems of anesthesia machines
- High
- Intermediate
- Low
71
List components of high press system
Consists of those parts that rcv gas at cylinder pressure
- hanger yoke
- hanger yoke check valve
- cylinder pressure regulator
- cylinder pressure gauge
72
List components of internedite pressure system
receives gas at relatively low and constant press (35-55 PSIG/pipeline press)
- pipeline inlets and press gauges
- vent power outlet accessory
- O2 flush valve
- supply failure alarm system
- second stage press regulator
- flowmeter valves
73
List components of low press system
components distal to the flowmeter needle
- flowmeter tubes
- vaporizers
- temp compensating bypass valve
- common gas outlet
74
When must a high priority alarm sound?
- if user adjustable limits are exceeded
- if continuing high pressure alarm is sensed
- for negative pressure
75
What are disconnect alarms based on?
- low pressure
- exhaled volume
- carbon dioxide
76
List the required monitors
- exhaled volume
- inspired O2 - w/ a high priority alarm w/in 30 sec of O2 falling below 18% (or a user adjustable limit)
- O2 supply failure alarm
- a hypoxic guard system must protect aganst less than 21% inspire O2 if nitrous is in use
- Pulse ox, BP, and EKG are also required
77
What is th PSI of O2 when it enters the anesthesia machine from the central supply source?
45-55 PSI
78
Where should check valves on the machine be located?
Downstream from the pipeline inlet to prevent reverse flow of gases thereby avoiding flow of gas from the machine to wall supply
79
What occurs when O2 from the E cylinder passes through the hanger yoke check valve and cylinder pressure regulator?
the pressure from the cylinder (2000 psi) is reduced to 40-50 PSI
80
Describ the wood's metal cylinder
a safety device that melts under excessive heat (>200 F) to allow the gas to escape preventing an explosion
81
what is the joule thompson effect?
a cooling effect once compressed gas is allowed to escape in open spaces
82
what is adiabatic heat of compression?
compression of cylinder contents into a small space generates heat and may cause combustion1
83
who develops the purity specs of gases?
US pharmacopecia and national formulary
