Gas delivery Flashcards
1
Q
Most efficient Mapleson during controlled ventilation
A
Mapleson D
2
Q
During spontaneous respiration, FGF = 2-3 x MV
During controlled ventilation, FGF = 1-2 x MV
A
Mapleson D
3
Q
Mapleson D is also called
A
Bain System
4
Q
What is the order of effectiveness in controlled ventilation in the the Mapleson system
A
D > B > C > A (Dog bites can ache)
5
Q
What is the order of effectiveness in spontaneous ventilation in the Mapleson system
A
A>D>C>B(All dogs can Bite)
6
Q
What system consists of inner tubing that delivers FGF directly to the patient who then exhales down the outer corrugated tubing to the reservoir bag and APL valve
A
The Bain System
7
Q
Which Mapleson system eliminates rebreathing, where higher fresh-gas flows are needed during SV than during controlled ventilation
A
Mapleson D
8
Q
A patient has a fever of 103.5,what should be done with the FGF and whats the rational
A
Increase the fresh gas flow due to the increase in co2 production
9
Q
Adjustments to the ventilatory pattern that allow the fresh-gas flow to constitute a larger proportion of the inspired gas includes all of the following except: A.Slow inspiratory time B.Low inspiratory flow C.Long Expiratory Pause D.Slow Rate E.Fast Total cycle time
A
E
10
Q
What are the disadvantages of the Bain Circuit
A
Kinks,Leaks,Disconnection of the the Inner tubing
11
Q
What is the advantage of the Bain Circuit
A
- Exhaled gas warms the fresh gas flow in the inner tubing thereby preserving humidity and warmth
- Ease of Scavenging through the overflow valve.
- Useful for head and neck surgery.
- Conserves humidity due to partial rebreathing
- Low Resistance to breathing by the tubing or circuit
12
Q
The rapid flow of gas through the expiratory limb, resulting in a slight negative pressure and collapse of the breathing bag.
A
Venturi Effect and used to test for leaks in The Bain Circuit.
With a leak from the inspiratory limb into the expiratory limb, the pressure in the latter rises, tending to inflate the reservoir bag if there was a leak
13
Q
Mapleson E is a is used in ?
A
Ayre’s T piece.
14
Q
which system has NO RESERVOIR BAG (the expiratory limb is the reservoir) AND NO POP-OFF VALVE!!!
A
Mapleson E
15
Q
What is rate of FGF during SV in the Mapleson E system
A
MVx2-3
16
Q
Name the characteristics of the Mapleson E system
A
No reservoir
No pop-off-valve
limited resistance in the tubing
17
Q
SInce there is no reservoir bag in the Map E system.
What acts as a reservoir
A
The open end corrugated tubing acts as the reservoir and should be have a lenght that exceeds the Tidal Volume of the patient.
18
Q
What is the sole determinant of rebreathing occuring in the Map E system
A
The FGF is ultimately the sole determinant of whether rebreathing occurs and directly influences the O2 concentration of inspired gas – if the FGF is not equal to the inspiratory flow rate then air will be entrained creating a dilutional effect.
19
Q
In the Map E system the FGF should Be equal to the inspiratory flow rate.True or false
A
True.
20
Q
With what kind of patients is the Map E used with
A
Pediatric patients weigh less that 20kg
21
Q
A modification of the Mapleson E Ayre’s T piece with an adjustable pop-off valve at the end of reservoir bag is called?
A
MAP F or Jackson Reese.
22
Q
Which Mapleson system Allows the application of continuous positive airway pressure or hand ventilation
A
Map F
23
Q
what Mapleson system Provides a visual indicator of respiration with the reservoir bag
A
Map F
24
Q
FGF equal to 2-3x mve is recommended to prevent rebreathing of exhaled gases in the Map F system,true or false
A
True
25
Disadvantages of the Mapleson F system include the floowing except:
(1) the need for high fresh gas inflow to prevent rebreathing, (2) the possibility of high airway pressure and barotrauma should the overflow valve become occluded, and (3) the lack of humidification. Lack of humidification can be offset by allowing the fresh gas to pass through an in-line heated humidifier
4. Air liquefication.
4.
26
What are the Basic Functions of a breathing circuit
1) Interface between the anesthesia machine and the patient
2) Deliver O2 and other gases
3)Eliminates carbon dioxide
CO2 absorbents eliminate CO2 in circle systems
Other breathing circuits require fresh gas flow (FGF) for elimination of CO2
27
3 Essential components of a breathing circuit
1. low resistance conduit for gas flow
2. reservoir for gas that meets inspiratory flow demand
3. expiratory port or valve to vent excess gas
humidifiers,pressure gauges,spirometers,peeps,waste gas scavengers
28
Requirements of a breathing circuit.
1) Deliver the gases from the machine or device to the alveoli in the same concentration as set and in the shortest possible time.
2) Effectively eliminate carbon dioxide
3) minimal apparatus dead space
4) low resistance to gas flow
5) allow rapid adjustment in gas concentration and flow rate
29
Name the Factors that will eliminate resistance in a breathing circuit.
1. Short tubing,
2. large diameter tubing,
3. avoid sharp bends,
4. caution with valves,
5. minimize connections
30
Beneficial effects of Rebreathing
1. Cost reduction
| 2. Adds humidification/heat to gases
31
Higher FGF is associated with less re-breathing in any system. T/F
T
32
Increase Dead space increases the chances of rebreathing T/F
T
33
What size of filter should placed in the anesthesia circuit to protect the machine from bacterial contamination
0.3micrometre filter
34
What is the meaning of HME
Heat and moisture exchanger
35
where will the HME be placed in the circuit
In the Y piece
36
What is the function of the HME
Inspiratory and expiratory barrier
37
Where would a standard filter be placed
In the Expiratory limb of the circuit.
38
When rebreathing is absent or minimal the concentration of Inspired oxygen is equal to that from the common gas outlet.True or false
T
39
What are the classifications of anesthetic delivery system and their specifications.
Open system:No reservoir/No rebreathing
semi open:Reservoir/no rebreathing
semi close:Reservoir/partial rebreathing
close:Reservoir and complete rebreathing
40
Examples of Insufflation ..open system
Blow by
open drop
simple face mask
nasal cannula
41
components of open system
No gas reservoir
No valve
No rebreathing
42
What rate of MVE should FGF be to prevent rebreathing
1-1.5 MVE
43
Advantages of Insufflation
Avoid direct pt contact
No rebreathing
No valves
44
Disadvantages of Insufflation
No ability to assist or control ventilation
May have CO2/ O2 accumulation under drapes
No control of anesthetic depth /FiO2
Environmental pollution
45
Name Mapleson system components
connection point to a facemask or ETT
reservoir tubing
fresh gas inflow tubing
expiratory pop-off valve or port
46
Which Mapleson system has no reservoir bag>
Mapleson E
47
When are the Mapleson system used
pediatrics
transport of patients
procedural sedation
weaning tracheal intubation (the T-piece)
Pre-02 during out-of-the-OR airway management
48
Best measure of optimal FGF to prevent rebreathing
Etco2
49
Name the differences present in the Mapleson system
locations of pop-off valve, fresh gas input, and whether or not a gas reservoir bag is present
50
ADvantages of Mapleson are
simplicity of design
ability to change the depth of anesthesia rapidly
portability
lack of rebreathing of exhaled gases(With adequate fresh gas flow)
51
Disadvantages of the mapleson system
lack of conservation of heat and moisture
limited ability to scavenge waste gases
high requirements for FGF
52
Co2 rebreathing depends on
Fresh gas inflow rate
Minute ventilation of patient
Mode of ventilation (spont v controlled)
CO2 production of individual patient (increased with fever, catabolism, etc)
Respiratory waveform characteristics
e.g., inspiratory flow, inspiratory and expiratory times, I:E ratio, and expiratory pause
Type of ventilation (spontaneous or controlled)
53
what are the components of an Ambu Bags
1. Non-Rebreather Valve
2. Self Inflating Bag
3. Co2 Washout depends on MVE
4. Will deliver high Fio2 if o2 source is ATTACHED
54
Is Mapleson System a flow inflating device or a self inflating device?
Flow inflating device that needs oxygen source to function.
55
Is ambu bag a flow inflating device or a self inflating device
Ambu bag is a self inflating device
56
Differences between Mapleson and Circle system
Mapleson
1. Bi-directional flow
2. Depends on Fresh gas flow to Eliminate C02
3. No Co2 absorber used
57
Some characteristics of the Circle systems are
1. Changes in anesthesia concentration can take some time to reach equilibrium.Hence higher FGF use in needed.
2. Unidirectional valves can be stuck causing higher resistance.
3. Minimizes pollution
4. conserves heat,humidity and anesthetic agent.
58
The circle system eliminates CO2 in the following ways
1. Allows carbon dioxide absorption during low-flow anesthesia and
2. elimination through the pop-off valve during high-flow anesthesia
59
The open circuit system is useful in the case of CO2 absorbent failure because?
Expired gas does not return to the patient since fresh gas flow is sufficient to get rid of C02 and hence create an open circuit
60
The Inspired CO2 should Zero if a circle system is used properly.True or False
True
61
If the CO2 absorbent becomes saturated and can no longer absorb carbon dioxide, How can we tell that the inspired CO2 has increased?
The waveform Capnogram will indicate inspired carbon dioxide throughout inspiration and will not return to baseline.
62
If the Co2 absorbent material has become saturated and the inspired Co2 has increased.Name 2ways to fix the issue of breathing in more Co2
2. Change the saturated absorbent material
| 1. Increase Fresh gas flow to exceed the MVE...this will create an open system
63
What limb should the Co2 absorber be placed in the circle system
The inspiratory limb and on the side of the reservoir bag
64
What is the rational of placing the co2 absorber on the side of the reservoir bag
This is done so that the resistance to inspiration can be overcome with assist or controlled ventilation
65
What limb shoulf the Co2 absorber be placed in the circle system
The inspiratory limb
66
What is the rational of placing the co2 absorber on the side of the reservoir bag
This si done so that the resistance to inspiration can be overcome with assist or controlled ventilation
67
Name the two ways to get rid of co2 in anesthesia systems
1. Absorption
| 2. Dilution
68
In Low Fresh gas flow what technique can we use to get rid of co2
Absorption(Co2 absorber)
69
In High fresh gas state What technique can we use to get rid of co2
Dilusion(High FGF dilutes the concentration Of Co2)
70
Using Co2 absorber ,conserves humidy and heat.True or false
True
71
What is the preffered location for FGF inlet valve on the circle system
This location is after the co2 absorber on the Inspiratory Limb,before the Inspiratory valve
72
what is the optimal position for the pop off valve to be placed in the circle system
Placement should be after the expiratory valve and before the reservoir bag on the expiratory limb
73
What is the preffered location for FGF inlet valve
This location is after the co2 absorber on the Inspiratory Limb,before the Inspiratory valve
74
The essential characteristics of the unidirectional respiratory valves in breathing circuits are?
1. low resistance
| 2. high competence
75
The primary sources of resistance in an anesthesia delivery system are?
The valves
The Co2 absorber
The Tracheal tube
76
When expiratory valve is wet, A much higher resistance is exerted into the system.t/f
True.
77
Name the characteristics of the unidirectional valve material
1. Hydrophobic: so that water does not accumulate and cause it to stick to the knive edge and unable to open when needed.
2. light weight and thin
3. Should be able to lift the valve with 0.31cm of h20 pressure.
78
Fairlure for the unidirectional valves to seal will result in?
Co2 rebreathing
79
Characteristics of the reservoir bag
Made of rubber or neoprene
Means for manual ventilation
Reservoir for oxygen and anesthetic gases
Adult size 3L(range 0.5-6L)
80
What are the standards of pressure that the anesthesia reservoir bag must adhere to?
Anesthesia reservoir bags must adhere to pressure standards, which allow a minimal pressure of approximately 30 cm H2O and a maximal pressure of approximately 60 cm H2O
81
What is the purpose of the Apl valve/pop-off valve.
AKA: pressure relief, pop-off, safety-relief valve•Purpose: 1.permits PEEP during SV or allows for pressure- limited controlled respiration•
2. Releases gases to scavenge or atmosphere exhaust port•
3. User-adjustable: clockwise – closes valve & increases pressure within system•
4. Provides control of pressure in system – pressure gauge on absorber•
5. Spontaneous Respiration:•valve fully open•close partially only if reservoir bag collapses•
6. Assisted Ventilation:•valve partially open•bag squeezed on inspiration•careful & frequent adjustments necessary•
7. Mechanical Ventilation- APL left open
82
What is the position of the APl valve during spontaneous respiration
valve fully open
| close partially only if reservoir bag collapses
83
What is the position of the Apl valve during Assisted Ventilation
valve partially open
bag squeezed on inspiration
careful & frequent adjustments necessary
84
What is the position of the Apl Valve during mechanical Ventilation
APL left open
85
At what pressure should the Apl Open
Pressure < 1cm of water
86
What are the characteristics of a breathing tube
Large bore, non rigid corrugated tubing
Clear plastic (historically rubber was used)
22 mm female fitting w/machine
Patient end – T piece 22 mm male, 15 mm female coaxial fitting
I meter in lenght with 400-500 Ml/m of lenght per internal volume
87
Functions of breathing tube
Reservoir
88
What is the most common breathing circuit used in the usa
Semi closed circle
89
what are the characteristics of a semi-closed circle
1. Allows for some re-breathing of agents and exhaled gases (minus CO2 due to CO2 absorption)
2. Uses relatively low flow rates (about 1-3L/min)
3. FGF is less than minute ventilation
4. Conserves some heat and gases
5. APL valve is partially closed and adjusted as needed; or ventilator is in use
90
What is the most common breathing circuit used in the usa
Semi closed circuit
91
When is the close circle used
Used in long surgical cases and in third world countries
92
Characteristics of a closed system
Inflow gas exactly matches metabolic needs/ O2 consumption of the patient using very low flows (O2 flow rate ~ @ 250 mL/min)
Total re-breathing of all exhaled gases after absorption of CO2
APL is closed
Change in gas concentrations is VERY slow
93
If the Inspired Co2 level is high or the waveform does not return to baseline,name the 2 steps to resolve these.
Increase the Fresh gas flow.
check the unidirectional valve there may be a stucked valve.
Change the co2 absorber.
94
Disadvantages of the circle system are?
Complex design
Has at least 10 connections
This sets the stage for potential leaks, obstruction, or disconnection
A third of malpractice claims are related to disconnects or misconnects of the circuit
Potential of malfunctioning valves
Stuck open= rebreathing
Stuck closed= airway obstruction
Increased resistance to breathing (above Mapleson)
Less portable and convenient than the Mapleson systems due to its bulkiness
Increased dead space BUT dead space ends at the Y piece
95
If the Inspired Co2 level is high,name the 2 steps to resolve these.
Increase the Fresh gas flow.
check the unidirectional valve there may be a stucked valve.
Change the co2 absorber.
96
Explain the Leak test
Set all gas flows to zero, occlude the Y-piece, close the APL valve, pressurize the circuit to 30 cm of water pressure using the O2 flush valve, ensure pressure holds for 10 seconds, listen for sustained pressure alarm, open APL valve and ensure pressure decreases
97
Explain flow test
Attach breathing bag to Y- piece, turn on ventilator, and assess integrity of unidirectional valves
98
What are issues we have with circle delivery system
```
misconnections or disconnections
leaks
valve failure
carbon dioxide absorber defect
bacterial filter occlusion
```
99
Which of the mapleson system is wasteful for Gases
B and C
100
what are the Characteristics of the Breathing Tube in the circle system
Low resistance
Light weight connection
flexible...prevents kinking
101
Name the components of a circle system
1. FGF source
2. Inspiratory and expiratory unidirectional valves
3. Inspiratory and expiratory limbs/ corrugated tubing
4. Y-piece connector
4. Adjustable pressure-limiting valve (APL valve, over-flow valve, or Pop-off valve )
5. Reservoir bag
6. CO2 absorber
102
Name the Desirable breathing system features
economy of fresh gas
conservation of heat (adequately warm gases)
adequate humidification of inspired gas
light weight
convenience during use
efficiency during spontaneous as well as controlled ventilation
adaptability for adults, children and mechanical ventilators
provision to reduce environmental pollution- safe disposal of waste gas
103
disadvantages of map A
proximal location of the overflow valve makes scavenging difficult
difficult to adjust during head and neck surgery
heavy valve can dislodge a small tracheal tube
104
Using Map A(Magill),how can we prevent rebreathing during controlled ventillation
Requires high FGF
105
Which of the Mapleson system is used in rescucitation situations
Mapleson C(water's Circuit)
106
Map B and C need high Fresh gas flows thereby making them Impractical to use.True or False
True
107
Which Mapleson system should be choosed theat will be most optimal for both controlled and spontaneous ventillation
Mapelson D
108
What are the characteristics of the Circle system
1. unidirectional gas flow via unidirectional valves
2. Components are arranged in a circle
3. Can be used as a semi-open, semi-closed, or closed system
4. Depends on the adjustment of the APL valve
5. Depends on FGF rate
6. Prevents re-breathing of CO2 by chemical neutralization
7. Allows re-breathing of other exhaled gases
109
advantages of Circle system
Relative stability of concentration of inspired gases
Conservation of moisture and heat
Low resistance (but not as low as Mapleson)
Can be used for closed-system anesthesia
Can be used with fairly low flows with no rebreathing of CO2
Economy of anesthetics and gases
Can scavenge waste gases
Prevention of OR pollution
110
The Mapleson F system is used in what scenario
The Mapleson F system is commonly used for controlled ventilation during transport of intubated patients
111
what happens in The Mapleson E system If the Fresh Gas flow is not Equal to the Inspiratory flow rate
It will entrain room air and create a dilusional effect
112
What is the difference in Fresh gas content between Map A and other Mapleson devices
Map A has only new Fresh gas Flow and other Map devices have a mixture of gases.
113
Why does Map A have only fresh gas and not a mixture of gases?
The other gases ..alveoli gas,dead space gas was vented out end expiration.
114
Characteristics of a Semi-open Circle system
1. No re-breathing occurs; very high flow of FGFs (10-15L/min) are used and eliminates rebreathing of gases
2. No conservation of wastes gases and heat .
3. APL valve is open all the way or ventilator in use
