Breathing Sys/CO2 absorbent/Scaveging Flashcards
(113 cards)
1
Q
What is dead space?
A
The space occupied by gases that are rebreathed without any change in composition - area of no gas exchange
2
Q
What 2 things make up anatomical dead space?
A
- patient’s conducting airways
- conducting zone of respiration
3
Q
What structures are included in the conducting airways?
A
nose
mouth
4
Q
What structures are included in the conducting zone of respiration?
A
nose
trachea
bronchi
5
Q
How to approximate anatomical dead space using IBW?
A
2 ml/kg
6
Q
Is anatomical dead space the majority of physiologic dead space?
A
Yes
7
Q
What is alveolar dead space?
A
The alveoli are ventilated with little or no perfusion - ventilation with no perfusion
8
Q
What structures is alveolar dead space comprised of?
A
Alveoli
9
Q
What is physiologic dead space?
A
Anatomical dead space + Alveolar dead space
10
Q
What is mechanical/apparatus deadspace?
A
dead space created by the patient circuit
11
Q
What increases mechanical dead space?
A
- masks
- ETT
- adding items between ETT and Y piece
12
Q
What things could be added between ETT and Y piece to increase dead space?
A
- gooseneck extenders
- humidifier filter
- straight connector
13
Q
What accounts for a majority of physioligc dead space DURING anesthesia?
A
mechanical dead space
14
Q
What decreases mechanical dead space?
A
tracheostomy
15
Q
Do ETT increase or decrease mechanical dead space?
A
They decrease because the entire Vt enters the dead as opposed to the mouth
16
Q
What does VT stand for?
A
Tidal volume
17
Q
What does VA stand for?
A
Alveolar volume
18
Q
What does VD stand for?
A
Dead space volume
19
Q
What 2 components make up VT?
A
VT = VA + VD
20
Q
With each breath, tidal volume (VT) is made up of ______ + gas that is ______
A
With each breath, tidal volume (VT) is made up of ALVEOLAR VENTILATION (VA) + gas that is DEAD SPACE (VD)
21
Q
What is the normal alveolar:dead space ratio? How would you see this ratio written?
A
- 2:1
- VA/VD
22
Q
What is the approximate dead space:tidal volume ratio? How would you see this ratio written?
A
- 1:3
- VD/VT
23
Q
For each breath, 1 ml/lb (lean body weight) becomes ___, 2 mlxlb-1 becomes ____, 3 mlxlb-1 constitutes the ____
A
For each breath, 1 ml/lb (lean body weight) becomes VD, 2 mlxlb-1 becomes VA, 3 mlxlb-1 constitutes the VT
24
Q
What is minute ventilation?
A
The total flow expired over 1 min
25
What is the algebraic expression for minute ventilation?
VT x f
- where f is RR
26
VE is synonymous with what?
- minute ventilation
- VT x f
27
What are the 2 equations for VE?
VE = VT x f
VE = VA + VD
28
When is rebreathing DESIRED? Why?
- when the patient is breathing previously ehaled gases and agents (O2, N2O, Air, sevo..)
- prevents waste
29
When is rebreathing NOT DESIRED? Why?
- when the patient is breathing previously exhaled CO2.
- Causes CO2 retention & dilutes gases/agents
30
What are 2 ways that CO2 is removed?
CO2 absorber/scrubber
Scavenger system
31
Does rebreathing CO2 dilute gases & agents? What does this do to speed of induction and emergence?
Yes, it can delay the speed of induction & emergence
32
What 3 factors influence rebreathing?
- FGF
- Mechanical dead space
- Design of breathing system (circle v mapleson)
33
If the volume of FGF is equal to or greater than patient's minute volume, is there rebreathing/CO2 retention?
No
34
If the volume of FGF is equal to or greater than patient's minute volume, must there be unobstructed expiration to atmosphere or a scavenging system?
Yes
35
In regards to apparatus dead space, increasing or decreasing the dead space decreases or increases the risk of rebreathing CO2?
In regards to apparatus dead space, INCREASING the dead space INCREASES the risk of rebreathing CO2?
36
At what 2 points during the case do we want higher flows?
- On induction during denitrogenation
- on emergence to blow off CO2
37
Do you want your flows higher or lower during maintaence phase of the case?
lower
38
Circle circuits are also known as what 2 names?
semi closed systems
closed systems
39
In a circle circuit, is rebreathing expected or not expected?
Rebreathing of inhaled agents/gase is expected, not CO2
40
Non rebreathing circuits are also known as what 3 names?
- semi opened system
- Bain
- mapleson D
41
In a non rebreathing circuit, is rebreathing desreable?
No, rebreathing is not
42
How is CO2 eliminated in circle circuits?
CO2 absorbent that scrubs exhaled CO2
43
In non rebreathing circuits, calculating _____ may be necessary to prevent rebreathing CO2
In non rebreathing circuits, calculating VE (MINUTE VENTILATION) may be necessary to prevent rebreathing CO2 - provided on circuit
44
Does rebreathing CO2 raise CO2 blood levels?
Yes
45
What are the 5 goals of the circle system?
- Deliver gas
- Remove co2
- Ace humidity
- Condition temperature
- Exclude room air
46
What are the 2 unidrectional resp valves in a circle system?
- inspiratory
- expiratory
47
What are the 2 overall purposes of the unidirectional resp valves?
- direct gas flow
- decrease dead space
48
When does the inspiratory valve open? When does it close?
- opens during inspiration
- closes during expiration
49
When does the expiratory valve open? When does it close?
- opens during expiration
- closes during inspiration
50
What size connecters is circle circuit tubing?
22 mm connecters
51
Is the scavenger system tubing the same as the circuit tubing? Does it have the same connector sizes?
No, different tubing, different connector sizing
52
What size connecters is the scavenging system tubing? What color?
- 30 or 19 mm connecters
- black or yellow
53
Why are the connecter for the circuit and scavenger different size/colors?
For safety, to prevent accidental inappropriate connections - leading to patient breathing CO2 and other gases out to scavenger
54
How would you describe the circle tubing appearnace?
It is corrugated.
55
What does corrugated mean?
flexible and prevents kinking
56
Approximately how long is the inspiratory and expiratory limbs of the circle circuit?
1 meter
57
Is dual limb circle tubing frequently used today? Which is type is considered standard?
No, universal F (single limb) is standard
58
What volumes are associated with dual limn circle tubing? What adult size connecters?
- 400-500ml
- 22 mm
59
What is a universal F or single limb tubing?
- breathing limb where there is a divider or tube inside a tube - both limbs in one
60
Which has higher volumes, single or dual limb?
dual limb
61
With 20 cmh20, which expand more, single limb or dual limb?
Dual
62
In the single limb, which is insp? Which is exp?
inner most is insp
outer most is exp
63
What does co-axial mean?
dual insp & exp limbs within 1 single corrugated tubing
64
Are inspired gases still warmed and humidified if using universal F tubing?
yes
65
What are 2 disadvantages to universal F circuits?
- increased insp resistance to breathing
- difficult to recognize if the inner tube/wall is intact
66
What 2 connectors are considered standard by ISO - all things related to airway
15 mm
22 mm
67
What are 3 types of airway filters that have 99.99% viral filtering efficiency between Y & ETT?
- HMEF w/ gas sampling port
- Airway filter with no humidification
- COVID/TB filters
68
Do airway filters between the Y and ETT add dead space? Which patient population should you be cognizant of with this?
Yes, peds patients
69
Should airway filters between the Y and ETT be used with a filter on the exp limb?
Yes
70
On which limb is it recommended you put the breathing circuit filter? Is placing one on insp and exp better than just exp?
- expiratory
- no
71
In what 2 circumstances might we see the use of electronically heated humidifiers in anesthesia?
- HFJV
- HFNC
72
What are the 2 names for the anesthesia breathing bags?
- reservoir bag
- rebreathing bag
73
What material is the reservoir bag made of?
Neoprene
74
What are the 3 main purposes of the reservoir bag?
- reservoir for anesthesia gases/agents
- means of manual/assisted ventilation
- visual assessment of spont ventilation (helps approx. volumes)
75
What are the 3 optimal sizes of reservoirs bags? Which is used for adults?
- 1, 2, 3 L
- 3 L
75
Should the vol of the reservoir bag exceed that of the insp capacity?
Yes
76
What is the max pressure of the reservoir bag?
60 cmH2O or 4x their stated capacity
77
What does APL valve stand for? What is it also known as?
- Adjustable pressure limiting valve
- Pop off valve
78
What is the purpose of the APL valve? What is it measured in?
- Permits excess volume of gas to exit circuit and on to scavenging system
- cmH2O
79
APL Valve: Which direction is open? Does that provide minimum or maximum pressure?
- counterclockwise
- minimum pressure
80
APL Valve: Which direction is closed? Does that provide minimum or maximum pressure?
- clockwise
- maximum (pressure remains in circuit)
81
APL Valve: While closing, when do you feel a click? At what pressure is the valve fully closed?
- above 30 cm h2o
- at 70 cm h2o
82
APL Valve: What does the term "adjusted" mean?
When the valve is in ANY position above open/minimum
83
What are the 2 types of APL valves? Which type are most APL valves?
- spring loaded (pressure regulated) and stem & seat (needle valve)
- most are spring loaded (pressure regulated)
84
What is manual mode of the APL?
Adjusted position where the pressure from the circuit needs to be high enough to lift valve open or forceful exhalation by patient to permit gases to exit to scavenger
85
What is spontaneous mode of the APL?
The valve is in the fully open position & gases easily go to scavenger - only taking 1cm h2o from exhalation of FGF
86
During spont breathing, is the APL open, adjusted or closed?
open
87
During Machine checkout - scavenger system check - and
after morning check of machine, is the APL open, adjusted or closed?
open
88
While placing mask on an awake and spontaneously breathing patient for induction and during emergence emergence, is the APL open, adjusted or closed?
open
89
During assisted ventilation, is the APL open, adjusted or closed?
adjusted
90
During machine check, is the APL open, adjusted or closed?
adjusted
91
During valsalva – brief positive pressure to lungs during case, is the APL open, adjusted or closed?
adjusted
92
During Machine check- circuit positive pressure check, is the APL open, adjusted or closed?
closed
93
During very, very brief positive pressure to lungs during case, is the APL open, adjusted or closed?
closed
94
What happens to the APL valve when the bag/ventilator switch is flipped?
Switching to Vent mode automatically isolates APL in traditional circle systems (Piston vents are different)
95
What can a manual PEEP valve on the inspiratory limb result in
Negative pressure pulmonary edema
96
What do oxygen analyzers measure? Where are oxygen analyzers found?
- inspired O2 concentration
- at the inlet to circle before insp valve
97
Where are flow and pressure sensors located?
on insp & exp limbs
98
Are CO2 absorbent canisters only found in circle systems?
Yes
99
What breathing system is most commonly used in anesthesia today?
circle/closed circuit systems
100
In open systems, is there a resevoir/rebreathing?
No
101
In semi opened systems is there a reservoir? Is there rebreathing?
- Yes, there is a resevoir
- No there is no re breathing
102
In open and semi opened systems, is there inspiration from atmosphere?
Yes
103
In open and semi opened systems, is there expiration to atmosphere?
Yes
104
In semi closed and closed systems, is there a reservoir?
yes
105
In semi closed systems, is there rebreathing? Can there be partial rebreathing?
- No there is no rebreathing but there can be partial at times
106
In semi closed systems, is there inspiration from atmosphere? Is there expiration to atmosphere?
- No, there is not inspiration to atmosphere
- Yes, there is expiration to atmosphere
107
In closed systems, is there a reservoir? Is there rebreathing?
Yes
Yes, complete rebreathing
108
In closed systems, is there inspiration from the atmosphere? Is there expiration to the atmosphere?
No
109
Is HFNC considered an open system? Is it a circle or non circle system?
It is considered an open, non circle system
110
Does HFNC cause minimal dead space, little resistance, use RA or O2, and not have rebreathing?
Yes
111
Does HFNC waste gas/increase pollution, have unpredicatable gas concetrations, cause a loss of heat/moisture, cause corneal abrasions, and have the inabilty to assist ventillation?
Yes
112
