Anesthesia Systems Flashcards
Requirements of breathing system 4
- deliver gas to alveoli in same concentration as set at shortest time possible
- eliminate co2
- minimal apparatus dead space
- low resistance
Desirable for breathing system to: 8
Economy of fresh gas, conserve heat, humidify inspired air, light weight, convenient, efficient in spontaneous and controllent vent, adapt to adults and peds, reduce pollution
How machines minimize resistance
Short tubing, large diameter, avoid sharp bends, caution w valves, minimize connections
Rebreathing
Why its good and bad
Reduces cost, adds humidification
Bad to rebreath co2
Higher fresh gas flow associated with what
Less rebreathing of any circuit
Dead space- increases chance of what
Where it is
Rebreathing co2. Where inspiratory and expiratory gas streams diverge
How to minimize dead space in system
Separate ins and exp limbs as close to pt as possible
Open systems characterized by 3
2 types
No: gas reservoir bag, valves, or rebreathing of exhaled gas
Insufflation/blow by, open drop
Ex of insufflation
Nasal cannula, head drape, steal induction (mask), bronchoscope port
Advantages of insufflation 4
Simple, avoids direct pt contact, no co2 rebreathing, no reservoir bags or valves
Disadvantages of insufflation 4
No ability to assist/control ventilation, may have co2/o2 accumulation under drapes, no control of anesthetic depth or fio2, environmental pollution
Schimmelbusch mask
What it is
Problems
Open circuit, cloth saturated with anesthetic over mask
Can cause hypoxia or too much drug
Open drop method
Example
Advantages 3
Ether mask
Simple, low cost, portable
Open drop method
Disadvantages 5
Poor control of inspired anesthetics, accumulate co2 under mask, hypoxia risk, spontaneous vent only, OR pollution and HCP risk
Semi open systems: 5 components
Face mask or ETT Pop off valve (APL) Reservoir tubing Fresh gas inlet Reservoir bag
Examples of semi open systems
Mapleson A-F
Bain
Circle
Group 1 maplesons
Which letters
Where stuff located
A
Pop off valve near face mask, FGF at opposite end
Group 2 maplesons
Which
Where stuff is
B and C
Pop off valve and FGF near face mask
Group 3 maplesons
Letters
Where stuff is
Opposite of what
D, E, F
FGF near face mask, pop off valve at opposite end
Mapleson A
Co2 rebreathing depends on 3
Fresh gas inflow rate
Minute ventilation of pt
Type of ventilation (spontaneous or controlled)
APL ___ to exhale w less resistance. ___ APL for positive end pressure
All the way open
Somewhat closed
Mapleson A best for what
Spontaneously breathing pts, dont need as much fresh gas flow, only need 1-2x minute ventilation of gas flow
`
Mapleson d best for what
Controlled ventilation
Mapleson D
Can be used for
FGF x mv what
Most __ mapleson during ___ ventilation
Spontaneous and controlled ventilation
2-3 spont, 1-2 controlled
Efficient, controlled
Mapleson E (__ __)
Most commonly used where
No __ __ and no __ __ __
If spontaneous, fgf what
T piece
Icu and pack
No reservoir back or apl valve
2-3
Mapleson f (__ __)
Modification of mapleson __
Difference
Popular for who
Jackson reese
E
Pop off valve and reservoir bag
Peds
Bain circuit
Modification of which mapleson
FGF tubing is where and allows what
D
Fgf inside of large corrugated tubing
Exhaled gas warms inspired gas, preserves heat and humidity
Bain circuit
Used for 2
FGF reqs
Disadvantage
Controlled or spontaneous vent
Same as mapleson d
Potential for tube leaks, kinking, disconnection
Ambu bag Modified mapleson \_\_ which what Capable of delivering what Reservoir is \_\_ \_\_ Requires \_\_ fresh gas flow Depends on \_\_ \_\_
A, non rebreathing valve High fio2 Self filling High Minute ventilation
Advantages of maplesons
6
Simple, lightweight, can provide positive pressure, low resistance, portable, more predictable and less room pollution w anesthetics
Disadvantages mapleson Requires: Control of what is variable: Possibility of what if fgf not maintained: Poor conservation of what 2
Calculation of fgf which varies with type of circuit and vent mode Anesthetic depth Co2 build up Heat and humidity Costly, special assembly
Circle system
Can be used as: depends on what, what varies for each
Prevents what
Allows what
Semi open, semi closed, or closed. Apl valve adjustment and fgf
Rebreathing of co2
Rebreathing of other exhaled gases
Circle system components: 7
Fresh gas flow source
Ins and exp unidirectional valves
Ins and exp limbs/corrugated tubing
Y piece, Apl, reservoir bag, co2 absorber
Order of circle system path 7
Y piece, ins limb, inhalation check valve
Fresh gas inlet, co2 canister, apl valve
Reservoir bag
Reservoir bag
Made of what
Neck is what
Tail is what
Neoprene or rubber
22 mm female fitting into male system
End opposite neck
Reservoir bag
Functions 4
Accumulation of gas during exhalation
Assist/control vent
Visual/tactile monitor to see breathing
Protects against excessive pressure
Breathing tubes
Material 2
Size, what fits to machine
Pt end is what
Plastic or rubber
22 mm female fits w machine
T piece 22 mm male 15 mm female coaxial fit
Breathing tubes
Functions 4
Reservoir, flexible, lightweight connection, low resistance
APL valve
Releases gas where
Clockwise does what
Provides control of what in system, where gauge is
Scavenge or atmosphere exhaust port
Closes valve and increases pressure
Pressure, on absorber
Apl valve:
spontaneous resp- Valve should be what
What for assist vent
Mechanical vent
Spont: fully open, partially closed only if reservoir bag collapses
Assist: partially open, bag squeeze on ins
Mech: valve closed
Peak airway inspiratory pressure
15-20 mmhg
If unidirectional valve working properly only dead space in circle system is where
Between y piece and patient
Adding extensions where increases dead space
Beyond y piece near pt
Circle system must follow rules:
Unidirectional valves between what on what
FGF cant enter system where
APL cant be located where
Pt and reservoir bag on ins and exp limbs
Between exp valve and pt
Pt and ins valve
Semi open circle system When used What doesnt occur What it requires No conservation of what APL is
Not often, for sedation Rebreathing High flow of gas, 10-15 to eliminate re breathing Gases and heat All the way open
Semi closed circle system \_\_ \_\_ breathing system Requires what kind of flow rate \_\_\_ heat and gas Some \_\_ \_\_ of agents Apl valve what
Most common Low flow rate, 1-3 lpm Conserves Re breathing Partially closed, can be adjusted
Closed circle system Where its used Inflow gas matches what Rebreathing is what Conservation is what Apl valve is
3rd world countries Metabolic needs of pt Total rebreathing after co2 absorbed Total of exhaled gases Closed
O2 consumption how to calculate
10 x kg ^3/4
Advantages circle system
Stability of inspired gases, conserves moisture and heat, prevents or pollution, can be used for closed system anesthesia, can be used w low flows w no rebreathing co2, economy of anesthetics and gases, can scavenge waste gases
Disadvantages circle system
Complex, 10 connections (leak potential), malpractice claims, potential malfunctioning valves, increased resistance of breathing, less portable than mapleson
Circle system leak test, how to
Set gas flows to zero, occlude y piece, close apl, pressurize circuit to 30 cm h20 using flush valve, make sure p holds 10 seconds, listen for sustained pressure alarm, open apple valve and make sure pressure decreases
Circle leak test doesnt do what
Assess integrity of unidirectional valves
Circle system test: flow test
Attach breathing bag to y piece, turn on vent, assess integrity of unidirectional valves
Do which circle system check every case
Flow test
