3/4: Inhalant Anesthesia Equipment Flashcards
(133 cards)
1
Q
What are 4 purposes for the anesthetic machine and breathing circuit?
A
- Deliver oxygen
- Deliver inhalant anesthetic
- Remove CO2
- Provide means for intermittent positive pressure ventilation (IPPV)
2
Q
What are the 5 main components of the anesthetic machine?
A
FROGS:
- Flowmeter
- Regulator
- VapOrizer
- Gas supply
- Scavenger
3
Q
What are the parts of the high pressure system?
A
- Oxygen cylinder
- High pressure hoses
- Cylinder pressure gauge
- Regulator for cylinder
4
Q
What are the parts of the intermediate pressure system?
A
- Flowmeter
- Oxygen flush valve
5
Q
What are the parts of the low pressure system?
A
- Vaporizer
- Breathing system
- Common gas outlet
- Common gas inlet
- Inspiratory and expiratory valves
- Breathing tube
- Reservoir bag
- Y-piece
- Pop-off valve
- Scavenging tubing
6
Q
What is the pressure of the high pressure zone? Intermediate pressure? Low pressure?
A
High = 1900-2200 psi
Intermediate = 37-55 psi
Low = <30 cm H2O
7
Q
What can be used to determine the volume of gas contained within the oxygen cylinder?
A
Pressure indicated on the cylinder pressure gauge
8
Q
T/F: You can tell how much nitrous oxide is left in the tank by reading the pressure gauge.
A
False;
Nitrous oxide is partially stored in liquid form; P gauge reads 745 until all liquid is gone, and then you just have the gaseous form.
9
Q
What are the possible cylinder sizes for oxygen?
A
E and H
10
Q
What is the color for oxygen in the U.S.?
A
green
11
Q
What is the capacity and pressure of an H tank?
A
6900 L
2200 psi
12
Q
What is the capacity and pressure of an E tank?
A
660 L
1900 psi
13
Q
What gas is denoted by yellow?
A
medical air
14
Q
What gas is denoted by blue?
A
nitrous oxide
15
Q
What is the diameter index safety system (DISS)?
A
Each plug has a different diameter and different thread to keep you from plugging in the wrong line.
16
Q
What is the pin index safety system (PISS)?
A
2 holes on the cylinder stem, 2 holes on the yoke;
Unique pin location for each medical gas
17
Q
What are the pin locations for oxygen? Air? Nitrous oxide?
A
Oxygen = 2, 5
Air = 1, 5
Nitrous oxide = 3, 5
18
Q
Where is the regulator located?
A
Between high and intermediate pressure systems
19
Q
What does the regulator do?
A
Reduces pressure from gas cylinder (1900-2200 psi) to working pressure (37-55 psi).
20
Q
What does the flowmeter do?
A
Controls rate of medical gas passing through the vaporizer
21
Q
Why is the flowmeter tube narrow at the bottom and wider at the top?
A
As the float moves up the tube, more gas can flow around the float, producing higher flow rates.
22
Q
Flow rate is determined by position of _____.
A
the float
23
Q
How is the flowmeter calibrated?
A
As a unit: flow tube, scale, and float
24
Q
How would you read this?
A
At the center of the float = 2 L/min
25
How would you read this?
At the top of the float = 3 L/min
26
What is the flush valve used for?
Rapidly delivers large volumes (35-75 L/min) of oxygen to common gas outlet/breathing circuit;
Fills depleted reservoir bag, flushes out anesthetic gas in circuit
27
What area is the oxygen flush valve located in?
intermediate pressure
28
What does the oxygen flush valve bypass?
flowmeter and vaporizer
29
When is it never okay to use the oxygen flush valve?
When the patient is connected to the breathing circuit
30
What does the vaporizer do?
Converts liquid anesthetic into vapor and adds measured amount of the vapor to flow of gases going to patient
31
What two ways can gas go?
1. Can bypass liquid anesthetic
2. Can go into vaporizing chamber and pick up vapor molecules --\> meets with bypass chamber --\> common gas outlet
32
Where in relation to the breathing circuit is the vaporizer located in modern systems?
Outside the circuit (high-resistance)
33
What is the method of regulating output concentration in a modern vaporizer?
Precision/concentration-calibrated, variable bypass
34
What is the method of vaporization in a modern vaporizer?
Flow-over the wick
35
Vaporizers have _____ filling systems.
keyed
36
Where is the vaporizer in this system?
Out of circuit (VOC)
37
Where is the vaporizer in this system?
In the circuit (VIC)
38
VOC have a _____ construction.
complex
39
VOC have a _____ resistance to breathing.
high
40
What provides the carrier gas in a VOC?
fresh gas inflow
41
T/F: In a VOC, vaporizer output is not affected by patient's ventilation
True
42
Which vaporizer is a precision vaporizer?
VOC
43
VOCs are inhalant agent \_\_\_\_\_.
specific
44
VOCs are _____ flow rate compensated.
temp/oxygen
45
Where are VICs located?
On inspiratory arm of the circle system
46
VICs have _____ construction.
simple
47
VICs have _____ resistance to breathing.
low
48
What provides the carrier gas in a VIC?
Inspiratory patient air flow
49
What inhalants can be used with a VIC?
multiple
50
Which vaporizer is a non-precision vaporizer? What does this mean?
VIC;
Anesthetic [] is unknown
51
What is the common (fresh) gas outlet?
Receives all gases and vapors from the machine and delivers mixture to breathing system.
52
The common gas outlet is a common location for \_\_\_\_\_; machines should be checked for _____ before each procedure.
disconnection, leaks
53
What are the functions of a breathing system?
1. Allows fresh gas and inhalant to be delivered from the machine to the patient
2. Eliminates the patient's expired CO2 to scavenger
54
What does a breathing system consist of?
Breathing hose, reservoir bag, pressure relief valve
55
What are the 2 types of breathing systems?
Rebreathing and non-rebreathing (NRB)
56
What is the purpose of one-way valves in a circle system?
Used to produce unidirectional flow of gas through system
57
Where does expired gas go in a circle system?
It is recycled back into system
58
Where does expired CO2 go in a circle system?
Removed by CO2 absorbent
59
What is the resistance in a circle system vs. a NRB?
It is higher in a circle system
60
What is the ideal oxygen flow rate in a circle system?
30 mL/kg/min
61
What is the Y-piece?
Connects endotracheal tube to breathing hoses of the rebreathing system
62
Gases in the inspiratory tube are directed _____ patient on inspiration.
toward
63
Gases in expiratory tube are directed _____ patient on expiration.
away from
64
What happens to air flow if one of the valves in a circle system do not work?
Gas will not move in a circular fashion
65
What is the fresh gas inlet?
Site of delivery of oxygen and anesthetic gas from common gas outlet of machine to the breathing system.
66
Where is the fresh gas inlet located?
After CO2 absorbent and before inspiratory one-way valve
67
What does the breathing circuit pressure manometer indicate?
P within breathing circuit
68
Peak inspiratory pressure should not exceed _____ in small patients.
15-20 cmH2O
69
What can the breathing circuit pressure manometer be used for?
To check for leaks in the machine and around the endotracheal cuff
70
How is a leak test performed?
1. Make sure all gas flows are set to 0
2. Close pop-off valve and occlude Y-piece
3. Turn flowmeter on and pressurize breathing system to 30 cmH2O
4. Turn flowmeter off
5. Do not use oxygen flush valve to completely inflate the reservoir bag
6. P should not fall more than 10 cmH2O within 30 sec
7. Open pop-off valve
71
Where are common areas for leaks?
Reservoir bag, breathing hose, CO2 absorbent canister, vaporizer
72
What is the recommended volume for a reservoir bag?
5-10 times patient's tidal volume;
10-15 mL/kg
73
What can happen if the reservoir bag is too large?
Can be difficult to observe respiration, and result in slower rates of change in anesthetic [] when vaporizer output changed (circle system)
74
What can happen if the reservoir bag is too small?
Inadequate gas supply to meet peak inspiratory volume, unable to provide safety margin against P buildup within breathing system
75
The pop-off valve is on the _____ side of the circuit.
expiratory
76
What is the purpose of the pop-off valve?
Allows exhaled gases, waste gas, unused fresh gas to exit the circuit --\> scavenger system
77
What is the P required to open the pop-off valve?
1-2 cmH2O
78
What can a completely closed pop off valve lead to?
Patient barotrauma or death
79
What does the scavenging system do?
Removes waste gases from the immediate workspace
80
In a passive system, where are waste gases diverted to and how?
To vent leading to outside work area by a hose connected to the APL
81
What is used to inactivate halogenated anesthetics in a passive scavenging system?
Activated charcoal canister
82
When are activated charcoal canisters changed?
When they gain 50g since before the first use
83
How does an active scavenging system work?
Vacuum pump creates negative pressure to collect waste gas
84
Active scavenging systems are more _____ and _____ to set up than passive systems.
complicated, expensive
85
What is the most common CO2 absorbent?
Soda lime
86
What is the makeup of soda lime?
80% calcium hydroxide
15% water
4% sodium hydroxide
87
How does a soda lime absorbent work?
CO2 passes thru soda lime --\> forms calcium carbonate --\> ethyl violet in absorbent changes color as the pH changes
88
When should absorbent be changed?
Observe at end of surgery and change if 1/3 violet
89
How is CO2 eliminated in a NRB?
By high fresh gas flows
90
What is the ideal oxygen flow rate in a NRB?
200 mL/kg/min
91
Where does inhaled gas pass through in a NRB?
Inner tube
92
Where does exhaled gas pass through in a NRB?
outer tube
93
What is the purpose of an endotracheal tube?
Transfers oxygen and inhalant from anesthetic machine into patient's lungs
94
ET tubes help to maintain a _____ airway.
patent
95
ET tubes help facilitate _____ \_\_\_\_\_ ventilation.
positive pressure
96
ET tubes protect the lungs from \_\_\_\_\_.
aspiration
97
ET tubes help prevent _____ of work environment.
contamination
98
What are the main parts of an ET tube?
Murphy eye, radiopaque marker line, pilot balloon, adapter
99
What is the purpose of the Murphy eye?
It is useful if the tube is obstructed against tissue or something else;
Provides another way for the gas to flow in and out
100
What size ET tube should be used?
Largest that will fit without causing trauma
101
ETT size can be based on width of _____ \_\_\_\_\_.
nasal septum
102
Other than the nasal septum width, how else can you estimate ETT size?
Palpate the cervical trachea
103
How many ETTs should you have available?
min of 3
104
How is the length of the ETT measured?
From tip of patient's shoulder to tip of the nose (minimize mechanical dead space)
105
What is a high-volume, low-pressure cuff?
Tracheal wall pressure is similar to intracuff pressure
106
What is a low-volume, high-pressure cuff?
Better protection against aspiration; intracuff pressure does not equal tracheal wall pressure
107
What do tracheal pressures \>48 cmH2O do?
impede capillary blood flow
108
What do tracheal pressures \<15 cmH2O do?
Increase risk of aspiration
109
When are guarded tubes useful?
In procedures where the ETT is likely to be compressed/kinked
110
What are disadvantages that occur when there is a leaky cuff?
Airway not protected from aspiration, difficult to keep patient anesthetized, pollutes environment
111
How is a cuff tested for proper inflation?
Administer least amount of air to inflate cuff and provide airtight seal so there is no leak when manual breath is given at 15-20 cmH2O
112
What can an excessive pressure in the cuff lead to?
tracheal necrosis
113
What does SGAD stand for?
supraglottic airway device
114
What does LMA stand for?
laryngeal mask airway
115
What are 2 alternatives to tracheal intubation?
SGADs and LMAs
116
What spp can SGADs and LMAs be used in?
cats and rabbits
117
SGADs and LMAs do not enter _____ or \_\_\_\_\_.
larynx, trachea
118
SGADs and LMAs form a seal around the \_\_\_\_\_.
glottis
119
Where should a laryngoscope be positioned?
At the base of the tongue, under the epiglottis, push down and pull forward
120
What is a ventilator?
Device designed to provide/augment patient ventilation;
Controls rate, volume/pressure, inspiratory/expiratory time of each breath
121
What replaces the rebreathing bag in a ventilator?
Bellows
122
What respiration phase occurs when the ventilator bellows collapse?
inspiratory
123
What respiration phase occurs when the ventilator bellows expand?
expiration
124
What is the suggested ventilator setting in small animals? Horses?
SA = 8-15 bpm with inspiratory time \<1 second
Horses = 6-10 bmp with inspiratory time 1-2 seconds (peak P 20-30 cmH2O)
125
What are CV effects of IPPV?
Decreased venous return/CO/BP
126
What type of system do induction chambers connect to?
NRB
127
What is the FIO2 provided by masks?
35-60%
128
Why should you not force a face mask onto a struggling patient?
It increases patient's metabolic oxygen consumption
129
What is a disadvantage of using a face mask?
Do not have an airway
130
What is a closed circle breathing system?
Uses absolute minimum oxygen flow rate to meet patient's metabolic oxygen requirements
**We don't use this**
131
What is the flow rate for a closed system?
3-5 ml/kg/min
132
What is the flow rate for a semi-closed system?
50-100 ml/kg/min initially;
20-30 ml/kg/min maintenance
133
What is the flow rate for a NRB system? Why is this necessary?
200 mL/kg/min;
High rate necessary to ensure expired gases not re-breathed
