Anesthesia Ventilators (Exam III) Flashcards
What were the deficiencies of older ventilators?
- Couldn’t provide high enough inspiratory pressure
- No PEEP
- Offered only volume control ventilation.
What allows driving gas to exit the bellows housing?
Exhaust valve
What is fresh gas compensation?
Machine compensation meant to prevent FGF from affecting set VT.
What is the inspiratory pause time?
What is another name for this?
Inspiratory Plateau = time in which lungs are held in the inflated position.
What is the ratio for inspiration to expiration?
1:2 typically
What is inverse ratio ventilation?
When I:E is inversed so that inspiratory time is double that of expiratory time.
What is minute volume?
VT for one minute = V̇T
When is peak pressure measured?
Inspiratory phase
What ventilator valve that allows excess gas to scavenged during exhalation?
Spill valve
What is work of breathing?
Energy expended by patient/ventilator to inhale and exhale.
What are the factors that affect delivered VT?
- FGF
- Compliance
- Leaks
Decreases in compliance cause a decrease in _____.
VT
What is the driving gas?
O₂ and/or medical air
What alarms are required on a ventilator?
Low Pressure
High Pressure
What is a good set point for our pressure limiting mechanism?
10 cmH₂O above the patients average inspiratory pressure.
10 cmH₂O above peak pressure.
What allows for observation of the bellows?
Bellows Housing (clear plastic cylinder)
What are the advantages/disadvantages of an ascending bellows?
- Safer
- Descends on inspiration
- Fails to rise if disconnected
Ascending bellows will _______ on inspiration.
descend
What are the advantages/disadvantages of a descending bellows?
- Rises on inspiration
- Continues to descend (d/t gravity) even if disconnected
What would occur with a bellows if an NGT were placed in the lung?
Bellow would collapse & “clap” due to lack of air in the lung.