Anesthesia Gas Machine Flashcards
What happens when the inspiratory unidirectional valve remains closed?
Airway obstruction
What happens when the unidirectional inspiratory valve remains open?
Dead space
What happens when the expiratory unidirectional valve remains closed?
Airway obstruction, breath stacking, barotrauma
What happens when the expiratory unidirectional valve remains open?
Dead space
When the unidirectional valves are working properly, where does dead space begin and where does it end?
Begins at the y-piece
Ends at the terminal bronchioles
When is the inspiratory unidirectional valve closed/open?
Closed during expiration
Open during inspiration
When is the unidirectional expiratory valve open/closed?
Open: during exhalation
Closed during inspiration
What are the two more common causes of inspired CO2?
Carbon dioxide absorbent exhaustion
Incompetent unidirectional valve
Which mapleson circuit is best for a spontaneously ventilating patient? Which is the worst?
All Dogs Bite
A: is the best
D: is ok
B: is the worst
Which mapleson circuit is best for controlled ventilation?
Don’t Be Arrogant
D: is the best for controlled
B: is ok
A: is the worst
Which mapleson circuit does not contain an APL valve or reservoir bag?
E
In the mapleson A circuit, where is the APL and fresh gas inlet?
APL: near patient
Fresh gas inlet: near bag
In the mapleson B circuit, where is the APL and fresh gas inlet?
Apl: near the patient
Fresh gas inlet: near the patient
(Very similar to C, just has corrugated tubing)
In the mapleson C circuit, where is the APL and fresh gas inlet?
APL: near patient
Gas Inlet: near patient
(Similar to B but does NOT have corrugated tubing)
In the mapleson D circuit, where is the APL and fresh gas inlet?
APL: away from patient
Gas inlet: near patient
(Opposite of A)
Which two mapleson circuits do not have a circuits do not have an APL valve?
E and F
What are the advantages of Mapleson circuits?
Less airway resistance (great for peds)
Convenient
Easily scavenged
Bain circuit prevents heat loss
What are the disadvantages of Mapleson circuits?
Increased dead space
Requires high FGF
Loss of heat and humidity
Inefficient use of inhaled anesthetics
Risk of environmental pollution
Unrecognized kinking of fresh gas hose (Bain circuit)
What is a general rule in the how much FGF required to prevent rebreathing?
2.5 times the patient’s minute vent.
What are some traits about the Bain circuit?
Modification of the Mapleson D
FGF enters an inner tube
What are some downfalls of the Bain circuit?
It’s possible for the inner tubing to become kinked or disconnected.
A Pethick test is required to test inner tube
