Exam 3 Anesthesia Ventilators (7/9/24) Flashcards
The definition of an “anesthesia ventilator” is an Automatic device designed to provide/augment these 2 things.
- Patient Ventilation
- Patient Oxygenation
What does the ventilator replace on anesthesia workstations?
Replaces the reservoir bag
What were/are some of the disadvantages to older ventilators?
- Provided only controlled mandatory ventilation (CMV)
- Couldn’t provide high enough inspiratory pressure
- Couldn’t provide PEEP
- Offered only volume control ventilation
What is the definition of barotrauma?
injury resulting from high airway pressures
What do decreases in compliance in a breathing system cause?
A decrease in tidal volume
In newer ventilators, this mode alters the volume delivered to compensate for system compliance.
Pressure controlled
The energy expended by the patient/ventilator to move gas in and out of lungs:
Work of Breathing
What is the definition of Peak Pressure?
A. Maximum pressure during the expiratory phase time
B. Maximum pressure during the inspiratory phase time
C. Minimum pressure during the expiratory phase time
D. Minimum pressure during the inspiratory phase time
B. Maximum pressure during the inspiratory phase time
In older vents, as ___ increased so did ___.
FGF
Tidal Volume
What is fresh gas compensation?
A means to prevent FGF from affecting Vt by measuring Vt and adjusting volume of gas delivered by the ventilator
Normal I:E ratio
1:2
The spill valve allows excess gases to be sent to the ____ during ___.
Scavenging system
Exhalation
This is the valve that opens to allow driving gas to exit the bellows housing:
Exhaust Valve
DURING INHALATION
What are some factors affecting ventilation?
- System Compliance
- Patient Compliance
- Leaks around tubes
True or False:
Leaks cause a decrease in tidal volume that can be compensated for by the ventilator.
FALSE:
Leaks cause a decrease in tidal volume that can’t be compensated for by the ventilator.
The Bellows Ventilators have a “Pressure-limiting mechanism” that limits _____ pressure.
What are some patient comorbidities/active issues that will cause a “High-Alarm”?
Limits Inspiratory Pressure
Things like ARDS, Pulm Edema may cause a High Alarm but we can alter the alarm settings to avoid the constant alarming
What is a good set point for the Pressure limiting mechanism on Bellows Ventilators?
10cm H2O above peak pressure with desired Vt
What squeezes gas out of the bellows, into the lungs?
How do the bellows get refilled?
Driving gas squeezes gas out of bellows into lungs
Exhalation and FGF in circuit refills bellows.
Ascending vs Descending Bellows:
Safer:
Descends on Inspiration:
Continues to descend even if disconnected:
“Standing”:
“Hanging”:
Rises on Inspiration:
Safer: Ascending
Descends on Inspiration: Ascending
Continues to descend even if disconnected: Descending
“Standing”: Ascending
“Hanging”: Descending
Rises on Inspiration: Descending
What may occur if there is improper bellows seating?
What about a hole in the bellows?
Improper seating: Inadequate ventilation
Hole: Alveolar hyperinflation/barotrauma OR the oxygen can leak out and we can also see inadequate ventilation here
A hole can be either too much or too little o2 getting to the patient