APEX: Breathing Circuits and Review Test Flashcards
Breathing circuits and Reservoir: Semi-open
No rebreathing and no reservoir
Breathing Circuit and Reservoir: Open
NO rebreathing with a reservoir
Breathing Circuit and Reservoir: Closed
Complete rebreathing with a reservoir
Breathing Circuit and Reservoir: Semi-Closed
Partial rebreathing with a reservoir
What is the primary function of the breathing circuit?
Deliver oxygen and anesthetic agent to the patient, while eliminating CO2 to prevent rebreathing.
How is CO2 removed from the breathing circuit?
Washout with a fresh gas flow or through chemical reaction with the CO2 Absorbent.
What do you call a non contained system where th patient exchanges gas with the atmosphere?
Open
Semi open system explain
Does not allow rebreathing of exhaled gas.
Semi-closed system explain
Allows rebreathing of exhaled gases
Semi open system : FGF vs MV
FGF is greater than MV
Semi-closed system : FGF vs/ MV
FGF is less than MV
In semi-closed system what does the unidirectional valve do?
Increases resistance
Closed system: Explain
in terms of rebreathing, FGF , scavenger, APL
Completre rebreathing
very low FGF
Gas does not exist to scavenger
APL is closed
2 ways to fix when the monitor shows that the patient is rebreathing CO2
Replace the CO2 absorbent
CONVERT the breathing system to a SEMI-OPEN system by increasing the FGF
Does increasing the MV prevent rebreathing?
NO. Pt will continue to rebreathe, at a faster rate.
Trick to diagnose unidirectional valve malfunction is to
Look at the beta angle during inspiratory phase.
Advantages of circuit system in terms of gas concentration , heat and humidity
Consistent inspired gas concentration. Maintains heat and humidity
Advantages of circuit system in terms of OR pollution
MInimizes OR pollution
Disadvantages of circuit system
Multiple places where disconnetion can occur.
Less portable
Unidirectional valve may be stuck open or stuck close
Dead space at ends of Y piece
CO2 exhaustion in the middle of the case and you cannot change the granules, first, what do you do about the system you are using
a closed or semi-closed system should be converted to a semi open circuit by increasing FGF to 5-8L/min.
CO2 exhaustion in the middle of the case and you cannot change the granules, first, you convered to semi open circuit and the problem isnt fix what do you do?
Check unidirectional valve competence
If you have an incompetent unidirectional valve , first what is the purpose of the valve
To ensure gas moves in the forward direction
When the unidirectional valve is incompetent, what will happen? What is the definite fix?
the patient will rebreathe exhaled gas.
Correct the valve. if you cant’ , convert to semi open
2 signs that you will see when the EXPIRATORY VALVE FAIlLS
- The beta angle becomes wider during the inspiratory phase
- Baseline does not return to zero .
What is the best configuration for spontaneous ventilation
Mapleson A
Bag is at beginning of circuit with the shape of a “T”
What is the purpose of the BAIN CIRCUIT?What is it tested with?
Tested with Pethick test
Delivers fresh gas through the inner tube.
Why is the PETHICK test performed for the bain system?
Because the inner tube is a risk for kinking and disconnection.
The Bain is a modified ______. Can it be used for spontanous or controlled ventilation ?
MAPLESON D. Can be used for both spontaneous and controlled ventilation .
For the BAIN circuit what do you do to prevent rebreathing,
FGF should be 2.5x the minute ventilation
Bain CIRCUIT explains
FGF enters circuit through the thin inner tubing and exhaled gas exits via the corrugated tubing
Outer tubing in Bain circuit should be
Transparent.
Pitfall of the bain circuit
INner tubing can become kinked or disconnnected. which will convert the tubing into dead space, putting the patient at risk for hypercarbia
Explain how you do the PETHICK TEST For the bain which is modified mapleson D
Occlude the elbow at the patient end of the circuit
Close the APL valve
Use the Oxygen flush valve to fill the circuit
Remove the occlusion at the elbow while flushing the circuit.
Interpreting the results of the PETHICK test: If the inner tube is patent, what will happen and meaning?
Venturi effect will cause the reservoir bag to collapse. The circuit is SAFE
Interpreting the results of the PETHICK test: If the inner tube is occluded what will happen and meaning?
The reservoir bag will remain inflated, CIRCUIT NOT SAFE
All Maples circuits lack _________ and a _________
Unidirectional valves
CO2 ABSORBER.
Resistance in mapleson circuit?
LOW, no valves no absorbent
Because low resistance in mapleson , it is attractive for what population
Pediatric
Only mapleson design with no APL or reservoir
Mapleson E
Worst configuration for controlled ventilation is the______why?
Mapleson A because there is no FGF and risk for hypercabia. Structure: FGF enters far from the patient and THE APL is close to the patient.
Mapleson from best to worst for CONTROLLED VENTILATION
DFE>BC>A
Mapleson A is the worst because what is needed at least to prevent rebreathing
FGF as high as 20L/min
The design that make the MAPLESON A worst for controlled ventilation also makes it the best for
SPONTANEOUS ventilation
Mapleson from best to worst for SPONTANEOUS VENTILATION
A>DFE> CB
Which circuit configuration as far as open or close does not have dead space?
Open , because it is open to the atmosphere.
What are the most common Mapleson circuits ?
D, E , F, also known as the “T”Piece group
In MAPLESON D, E,F where does the FGF enter and where is the APL located
FGF enters at the proximal end of the circuit and the APL is located distally near the reservoir bag.
Excellent choice for controlled breathing
MApleson D because it is the reverse of mapleson A.
The MAPLESON D is an example of
SEMI-OPEN
Bag reservoir = yes
Rebreathing = no
Semiopen circuit is
Mapleson A-F
Bain system
Circle system w/ FGF>Ve
Which circuit contains a reservoir bag but does not allow rebreathing of exhaled gases
Semiopen
A circle system with a FGF of 3L/min is an example of a
Semiclosed
Predecessor to BAIN system?
Mapleson D.
There is _______of exhaled gases if the _____is high enough. Can ventilation be controlled with that technique?
NO REBREATHING;FLOW;
cannot be controlled with that techniques atmospheric air is entrained unpredictably
Why should the APL valve be fully open during spontaneous ventilation?
So pressure remains negligible during both inspiration and expiration.
As far as FGF and MV what is sufficient to prevent rebreathing?
FGF= MV
Best Mapleson for spontaneous ventilaiton
A
Mapleson D is efficeint during? Why ?
Controlled ventilation because FGF forces alveolar air away from the patient and toward the APL valve
What is the role of silica for the soda lime?
If you increase the hardness of soda lime by adding sillica, it minimizes the risk of inhlation of sodium hydroxide dust and also decreases resistance of gas flow.
BEcause of this , dead space is limited to the distal area of the point of inspiratory and expiratory gas mixing at the Y-piece
Unidirectional valves
