Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Nurse Anesthesia Summer 19 > Anesthesia Delivery Systems > Flashcards

Anesthesia Delivery Systems Flashcards

You may prefer our related Brainscape-certified flashcards:
NCLEX-RN® flashcards NCLEX-PN® flashcards
1
Q

Types of Open System

A
  1. insufflation
  2. open drop
  3. blow by
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Types of Semi Open Systems

A
  1. Mapleson (A-E)
  2. Brain
  3. Jackson Rees
  4. Circle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Types of Semi Closed Systems

A

Circle System

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Closed System

A

Circle System

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Basic Functions of a Breathing circuit

A
  1. connects anesthesia machine to pt
  2. delivers C02 and other gases
  3. eliminates C02
    - circle system = C02 absorber
    - other circuits = fresh gas flow for C02 elimination

**C02 absorber recycles gas, saves money and keeps gas warmed and humidified

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

3 Essential Components of a Breathing circuit

A
  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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Peripheral Components of Breathing circuit

A
  • humidifier (provide warmth and moisture)
  • spirometer (measure ventilation
  • pressure gauges
  • filters (bacterial filters, placed on expiratory limb)
  • gas analyzer (sampling sites for gas analysis)
  • PEEP
  • waste gas scavenge (keep OR from being contaminated with waste gas)
  • mixing/ circulating device.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Requirements of a Breathing circuit

A
  1. deliver SET CONCENTRATION of gases from machine to the alveoli in SHORTEST possible time
  2. effectively eliminate C02 (high C02 = dilated vessels = hypotension tachycardia, increased ICP)
  3. minimal apparatus dead space (space from end of tube to y connector)
  4. low resistance to gas flow
  5. allow rapid adjustment in gas concentration and flow rate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Desirable Breathing system features

A
  1. economy of fresh gas (least amount possible)
  2. conservation of heat (warm gases)
  3. adequate humidification of inspired gas
  4. light weight
  5. convenience during use
  6. efficiency during spontaneous and controlled ventilation
  7. adaptability for adults, children and mechanical vents
  8. provision to reduce environmental pollution- safe disposal of waste gas
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Consideration of Breathing Circuit

A
  1. Want low Resistance (short tubing, large diameter tubing, corrugated tubing, no sharp bends, minimize connections, caution with valves
  2. Rebreathing benefits
    But NOT rebreathing C02
    (reduces cost, adds humidification/heat to gas)
    *higher FGF less rebreathing C02**
  3. Increased Dead space increased chance of rebreathing C02 (dead space ends at the Y connector; where insp and exp gas separate)
  4. Dry gases/ humidification
  5. Manipulate inspired content
    (concentration of inspired gas most closely resembles the common gas outlet when rebreathing is absent/ minimal)
  6. Bacterial Colonization;
    but filters add weight and can clog
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Y connector

A
  • where inspiratory and expiratory gas streams diverge/ separate
  • dead space ends at the y connector
  • minimize dead space by have y connector; separation of ins. and exp. streams as close to the pt as possible
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Bacterial Filters

A

American Association of Anesthesiology recommends a “bacterial filter with an efficient rating of more than 95% for particle sizes of 0.3 μm should be routinely placed in circuit where it will protect the machine from contamination with airborne infectious disease

*standard filters are placed on the EXPIRATORY limb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

HME

A

bacterial filter that both filters and performs heat and moisture exchange

*placed at y piece and serve as BOTH Inspiratory and Expiratory barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Classifications of Anesthesia Delivery Systems

A

Is a Reservoir used and does rebreathing occur

  1. Open;
    no reservoir 🚫
    no rebreathing 🚫
  2. Semi- open;
    Reservoir ✔️
    no rebreathing 🚫
  3. Semi- closed;
    Reservoir ✔️
    partial rebreathing ⭕️
  4. Closed- reservoir;
    Reservoir ✔️
    complete rebreathing ✔️
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Circle system

A

*has to have a reservior

semi-open; reservoir, no rebreathing

semi-closed; reservoir and partial rebreathing

closed- reservoir; reservoir and complete rebreathing

*type of circle system is determined by type of fresh gas flow (FGF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Open system

A

NO gas reservoir bag
NO rebreathing of exhaled gas
NO valves

Types;
open drop
insufflation (blow by, NC, simple face mask)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Semi- open system

A

Reservoir
NO rebreathing

ex. non rebreather face mask
mapleson circuit (FGF depends on design)
circle system (FGF > minute vent)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Semi- closed system

A

Reservoir
PARTlAL rebreathing

ex. Circle system (FGF > MV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Closed- Reservoir

A

Reservior
NO rebreathing

ex. circle system (FGF > MV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Insufflation

A

ex. blow by, NC, tent, bronchoscopy port, insufflation under OR drapes and “steal induction”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Insufflation Advantages

A
  1. No direct pt contact
  2. No rebreathing of C02
  3. Nothing to break; No reservoir bag or valves
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Insufflation Disadvantages

A
  1. No ability to assist or control ventilation
  2. May have C02 or 02 accumulation under drapes
  3. No control of anesthetic depth/ Fi02
  4. Environmental pollution (think of blow by flying al over the room
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Steal Induction

A

pediinhalation induction

  • child is naturally asleep upon arrival to OR
  • breathing circuit s primed with N20 and 02, with high flows you hover the mask near their face and gradually bring it closer and closer, once truly asleep, place mask on face
  • after child get 1-2 min of breathing N20, sevoflurane is administered inna single increase to 8% (adequate monitoring ASA) and child tx to OR table

**once mask on face it becomes semi open; reservoir and partial rebreathing

**child is not touched or disturbed, technique is traumatic and avoids exposing child to strange OR surroundings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Mapleson Systems Components

A
  1. connect to facemark or ETT
  2. Reservoir tubing
  3. Fresh gas inflow tubing
  4. expiratory pop off valve
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Mapleson system types

A

A, B, C, D,
E (T piece)
F (Jackson Rees)

**difference in each type:
1. location of the pop- off valve
2. position of FGF input
3. presence of reservoir bag
^in relation to pt connection

Spontaneous breathing pt:
A>D>C>B
all dogs can bit
A is best for spont breathing bc of location of pop off valve right neat facemark and with spont breathing you have an end expiratory pause, so everything you inhale is fresh gas bc excess. goes out through pop off

Controlled ventilation
D>B>C>A
dog bites can ache

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Uses of Mapleson systems.

A
  1. Pedi
  2. transport of pt
  3. procedural sedation
  4. weaning tracheal intubation
  5. Pre-02 during out of OR airway management (ex: in radiation with pt but can’t be in room with them)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Endtidal C02. relationship with rebreathing

A

loss of return to baseline on etC02 wave = rebreathing

increase FGF to eliminate rebreathing

**best measure of optimal FGF to prevent rebreathing

28
Q

Advantages of Mapleson System

A
  1. simple design
  2. ability. to rapid change depth of anesthesia
  3. Portability
  4. 🚫 rebreathing of exhaled gas with adequate FGF
29
Q

Disadvantages of Mapleson System

A
  1. 🚫 conservation of heat/ moisture
  2. limited ability to scavenge waste gases
  3. Not efficient require high FGF (to prevent rebreathing of exhaled gas)
30
Q

3 functional groups of Mapleson Systems

A

Mapleson A: pop-off near facemark, FGF located at opposite end (opposite of D)
*best for. spont breathing

Mapleson D,E,F: FGF near facemark, pop-off located at opposite end (opposite of A)
*best for controlled vent

Mapleson B & C: pop-off and FGF located near facemark *least efficient (wasteful, EVERYTHING leaves through pop-off on expiration

31
Q

Mapleson best for Controlled Ventilation

A

D>B>C>A
Dog bites can ache

(D, E, F are the same)

32
Q

Mapleson best for Spont breathing

A

A>D>C>B
All dogs can bite

ranked in order by efficieny

33
Q

Dependent factors of C02 rebreathing

A
  1. FGF rate
  2. Minute Vent of pt
  3. Mode of ventilation
    (spontaneous vs controlled)
  4. C02 production of pt
    (increased with fever, catabolism)
  5. respiratory waveform characteristics (inspiratory flow, I:E ratio, expiratory pause)
  • adjusting vent pattern;
  • slow iTime and low inspiratory flow allows FGF to constitute a larger portion of the inspired gas

-long expiratory pause or slow rate more completely rids exhaled gases and reduces rebreathing

34
Q

Mapleson A

A

“Magill”

  • most efficient for Spontaneous ventilation
  • least effective for CV requires up to 20L/min of FGF
  • impractical design for OR
  • proximal location of pop-off valve makes scavenging difficult
  • hard to adjust during head/ neck surgery
  • heavy valve can dislodge small ETT
  • NO rebreathing with SV when FGF is at least 1x MV
  • Requires large FGF to eliminate rebreathing during CV
35
Q

Mapleson B

A
  • Rarely used
  • Requires high FGF to prevent rebreathing
  • inefficient/ impractical for SV or CV

-corrugated tubing connecting rest of system to reservoir bag
(blind limb where fresh gas, dead space and alveolar gas mix)

*close proximity of APL valve and FGF provides potential for mixing of inspiratory and expiratory gases

36
Q

Maplseon C

A

‘Water’s circuit without absorber’

  • used in resuscitation situations and pt transfer
  • same as B, rarely used, requires high FGF to prevent rebreathing
  • close proximity of APL valve and FGF provides potential for mixing of inspiratory and expiratory gases
37
Q

Mapleson D

A

‘Brain’ system; inner tubing that delivers the FGF directly to pt, and exhales down outer corrugated tubing to reservoir bag and APL valve
(inner tubing not visible make sure to perform test to check for disconnect)

  • Most efficient for Controlled Ventilation and second best for Spont. ventilation
  • FGF close to facemark and pop-off valve located on opposite end (reverse of mapleson A)

*Controlled vent
FGF = 1-2 x MV

*Spont. vent
FGF = 2-3 x MV

38
Q

How to test for disconnect on ‘Brain’ circuit

A
  1. occlude the inner tube at the pt end using finger or end of 2ml syringe, if connected back pressure is created on the FGF and flowmeter bobbins dip
  2. Rapid flushing of FGF through an intact system causes reservoir bag to collapse (Venturi effect)
    * if disconnect present reservoir bag will inflate with rapid flush because it will cause an increased pressure in the expiratory limb
39
Q

Mapleson D controlled ventilations considerations

A
  • more efficient system
  • factors affecting rebreathing (Minute Vent & Flow rate) are controlled by anesthetist

allows for a lower FGF = more efficient

FGF 70mL/kg/ min = 𝑉˙𝐴V˙A

*higher FGF >100 ml/kg/min
PaC02 dependent on MV

*lower FGF <90 ml/kg/min
PaC02 independent of MV

  • increasing RR to eliminate PaC02 decreases the expiratory pause and increases rebreathing which increases inspired C02 (FiC02) and no change to PaC02
  • adjustments to vent that reduce rebreathing
    1. slower iTime or lower inspiratory flow = larger proportion of FGF in inspired gas
    2. long expiratory pause or slow RR = more wash out of exhaled gases
40
Q

Brain circuit

A
  • modification of Mapleson D
  • FGF enters circuit near reservoir bag BUT fresh gas delivered at pt end of circuit
  • FGF tubing within large bore corrugated tubing
  • *this allows exhaled gas to warm inspired gas (preserves heat and humidity with no added weight to circuit)

Risk for inner tube leaks, kinks, disconnections

41
Q

Mapleson E

A

T-piece

  • open ended corrugated tubing acts as inspiratory reservoir, length of tubing must exceed pt tidal volume
  • NO reservoir bag - expiratory tubing acts as reservoir
  • NO POP-OFF valve
  • on expiration tubing fills with dead space and alveolar gas which is then flushed out by FGF
  • commonly used to administer 02 in ICU and PACU settings

** SV: FGF = 2-3 x MV

42
Q

Mapleson F

A

Jackson-Rees most used
(modification of mapleson E ‘T- piece’)
-unofficial 6th mapleson

  • commonly used for controlled ventilation during transport of intubated pt
  • adjustable pop-off valve at the end of reservoir bag
  • flow inflating
  • allows application of continuous positive airway pressure or hand ventilation
  • provides visual indictor of respiration with reservoir bag
  • degree of rebreathing depends on ventilation (spontaneous versus controlled) and adjustment of the pressure-limiting overflow valve (venting).
  • FGF = 2-3 x MV to prevent rebreathing of exhaled gases
43
Q

Advantages of Mapleson F

A
  • minimal circuit dead space
  • minimal resistance
  • can be used for SV and CV
  • inexpensive
  • used with facemark or ETT
  • lightweight
  • easily repositioned
  • scavenging systems can be added to reduce pollution of anesthetic gas into atmosphere
44
Q

Disadvantages of Mapleson F

A
  • high FGF to prevent rebreathing.
  • risk of occlusion of popoff valve creating high airway pressures increasing risk of barotrauma to pt
  • lack of humidification (offset it by allowing. FGF to pass through in-line heated humidifier)
45
Q

Ambu bag

A

‘manual resuscitator’
critical piece of equipment and part of morning check

  • non rebreathing valve
  • self inflating bag
  • can deliver high Fi02 w/ 02 reservoir attached
  • reservoir self fills w/ intake valve
  • elimination of C02 depends on MV
46
Q

Safety features incorporated into manual resuscitator

A

biggest risk is barotrauma

-ambu adult Mark IV; uses elasticity of outer cover go bag to limit the pressure developed
7kPa = 70 cmH20)

  • pedi versions uses pressure limited valve (4kPa = 40cm H20)
  • Laerdal range also used pressure limiting features
47
Q

Non rebreathing valve of Ambu bag

A
  • located at opposite end of bag from gas inlet
  • have PEEP valve

JOB

  • ensures gas flows out of bag and ONLY into pt port on inhalation
  • exhaled gas escapes through expiratory port without mixing with fresh gas stored in bag on exhalation
48
Q

Gas inlet on ambu bag

A
  1. one- way flap valve
  2. small bore nipple
  3. wide bore inlet
  4. reservoir system
49
Q

reservoir system of gas inlet on ambu bag

A
  • final concentration of 02 delivered is dependent on added 02 and how diluted it is from room air in the self inflating bag
  • store the oxygen brought into system from nipple
  • must have overflow valve to prevent overfilling of 02
  • must have entrainment valve to allow access to room air for when 02 not available or need lower concentration of 02
  • when minute vent (TV x RR) is greater than volume given bag will expand and supply all the gas for ventilation (100% 02)
50
Q

small bore nipple of gas inlet on ambu bag

A
  • allows admixture of 02

* mounted on gas inlet

51
Q

wide bore inlet of gas inlet on ambu bag

A

-supplies bulk of gas entering bag (usually air)

52
Q

one-way flap valve of gas inlet on ambit bag

A

-fitted to inlet of self inflating bag

-bag squeezed, increased pressure inside bag, valve closes
(prevents gas going to back through inlet)

-bag released, bc its self inflating fresh gas from gas inlet it drawn in (can be air or 02 or mixture of both)

53
Q

Circle system

A
  • almost all anesthesia machines use some form a circle system
  • C02 absorption during low flow (semi closed & closed system dependent on APL valve)
  • C02 elimination via pop off valve during with FGF during high flow anesthesia (semi open system aka NO rebreathing)
  • minimizes environmental pollution
  • lower FGF than mapleson
  • conserves heat/ humidity and anesthetic agent (rebreathing other exhaled agents)
  • circular flow (unidirectional)
54
Q

Similarities between Mapleson and Circle system

A
  1. accept FGF (with semi-open circle system)
  2. eliminate C02
  3. give pt enough volume of gas from reservoir to meet inspiratory flow and volume needs
  4. both can be semi open systems
  5. both low resistance (mapleson a little lower)
55
Q

Difference between Mapleson and Circle system

A

circle system =unidirectional flow
mapleson = bidirectional flow

circle system uses C02 absorber
mapleson uses FGF to rid C02

circle system can be be semi- closed or closed system
circle system bulkier and more complex design

56
Q

7 commonest of Circle System

A
  1. FGF source
  2. unidirectional valves
  3. inspiratory and expiratory limbs (with corrugated tubing)
  4. Y- piece
  5. APL valve/ Pop-off/ Over-flow
  6. Reservoir bag
  7. C02 absorber
57
Q

Breathing circuit tube characteristics

A

-large bore 22mm, non rigid, 1 meter long corrugated tubing
(resistance to gas flow very small < 1cm H20/ L/ min of flow)

  • internal volume 400-500 mL/m of length
  • clear plastic (used to be rubber)
  • 22 mm female fitting w/ machine
  • patient end – T-piece 22 mm male and 15 mm female coaxial fitting
58
Q

Breathing circuit tube functions

A
  • flexible
  • low resistance
  • lightweight connection
  • reservoir
59
Q

dead space

A

from y- connector to terminal bronchioles

60
Q

Semi- open circle system

A

No rebreathing with very high FGF (10-15L/ min) to eliminate C02 and rebreathing
*C02 absorber not doing much, will last longer

  • no conservation of waste gases
  • no conservation of heat and moisture
  • APL valve open all the way or vent in use
61
Q

Semi- closed circle system

A

**most commonly used breathing system

  • PARTIAL rebreathing of agents and exhaled gases (not C02 bc of absorber)
  • relatively low flow rate (1-3L/ min)
  • FGF less than minute vent
  • conserves some heat and gases
  • APL valve PARTIALLY closed, adjust as needed, or vent in use
62
Q

Closed circle system

A
  • used for LONG surgical cases
  • third world countries (conserves gas)

-inflow gas EXACTLY matches metabolic demands
02 consumption of pt using very low flow rates

  • complete rebreathing of all exhaled gases after C02 absorption
  • APL valve closed
  • change in gas concentration is VERY SLOW (increase volatile again and FGF)
63
Q

Advantages of the Circle system

A
  1. stable concentration of inspired gas
  2. conservation of heat and moisture
  3. saves money on anesthetics and gases
  4. low resistajnce (mapleson lower)
  5. fairly low FGF with no rebreathing of C02
  6. can be used for closed- system anesthesia
  7. can scavenge waste gases
    preventing OR pollution
64
Q

Disadvantages of Circle system

A
  1. complex design
  2. ATLEAST 10 connections
    (risk of leaks, obstruction, disconnect)
    **1/3 malpractice claims are r/t disconnects or misconnects of circuit
  3. Risk of malfunctioning valve
    stuck open = hypercarbia
    stuck closed = airway obstruction
  4. increased resistance to breathing ( > than mapleson)
  5. Bulkier; less portable/ convenient than mapleson
  6. increased dead space; which ends at end of y-piece where insp and expiratory separate
65
Q

Circle system Leak Test

A
  • set all gas flows to zero
  • occlude y- piece
  • close APL valve
  • pressurize circuit to 30 cm H20 by using 02 flush valve
  • ensure pressure hold for 10 seconds and activates sustained pressure alarm
  • open APL valve and ensure pressure decreases
  • does NOT assess unidirectional valves separate test)
66
Q

Circle System Flow test

A
  • assess integrity of unidirectional valves
  • attach breathing bag to y-piece
  • turn vent on
  • assess integrity of valves
67
Q

Breathing Circuit issues

A
  1. misconnections and disconnections
  2. leaks
  3. valve failure
  4. C02 absorber defect
  5. bacterial filter occlusion

Nurse Anesthesia Summer 19 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions