10. Adv Ventilator Modes Flashcards
assisted breath
vent gives breath at BEGINNING of spontaneous breath
assisted breath: pro
help pt achieve larger tidal volume
stacked breath
vent gives breath:
in MIDDLE of spontaneous breath
or
during EXPIRATION
stacked breaths cause
coughing/bucking
overinflated lungs
barotrauma
spontaneously ventilating patients will better tolerate ________ breaths
assisted breaths
assist control
every spontaneous breath is assisted
ensures minimum respiratory rate is met
during assist control, the AA sets _____
minimum respiratory rate
SIMV is similar to
volume control
pressure control
is the vent sensing patient breaths in IMV?
no
IMV
ventilator will deliver a certain number of mechanical breaths per minute, regardless of the pt’s spontaneous rate
SIMV
set # of minimum mechanical breaths per second
vent senses spontaneous breaths
SIMV vs IMV
SIMV senses breath
IMV does not sense breath
are all breaths assisted in SIMV?
no - only the ones that occur at the same time as the mechanical breath
pressure support
every single spontaneous breath is assisted
PSV benefits
decr work of breathing
larger tidal volumes
decr atelectasis
lowers CI for SV in certain pts
what can you adjust in PSV
trigger sensitivity
amount of (+) pressure
min resp rate
PEEP
slope
inspiratory term
trigger sensitivity too low
vent wont sense spontaneous breaths
trigger sensitivity too high
vent might sense cardiogenic oscillations and may deliver breaths when pt isnt breathing
potential problem with high ventilator sensitivity
can make you think the pt is breathing faster than they really areno
normal inspiratory flow
15L/min
what will trigger pressure supported breaths
small respiratory efforts with low tidal volumes
increase PSV sensitivity
decrease trigger L/min
(lower flow)
decrease PSV sensitivity
increase trigger L/min (higher flow)
situation to INCR trigger sensitivity (DECR flow)
pt recovering from NMB and vent is not picking up spontaneous respirations
situation to DECR trigger sensitivity (INCR flow)
with cardiogenic oscillations during low respiratory rates
inspiratory term percentage
how long the vent will support each breath
25% inspiratory term
pressure supported breath will be terminated once the inspiratory flow rate decreases to 2.5L/min
75% inspiratory term
pressure supported breath will be terminated once the inspiratory flow decreases to 7.5L/min
incr inspiratory term %
decr duration of assistance
decr inspiratory term %
incr duration of assistance
decr inspiratory term % allows for
a larger tidal volume without increasing positive pressure delivered
pt that may benefit from decr inspiratory term %
obese pt on LMA
mandatory minute ventilation (MMV)
minimum minute ventilation
- mechanical breaths delivered if pt is not meeting minimum MV
- spontaneous breaths are assited
during BiPAP, is the positive pressure higher during inspiration or expiration?
positive pressure is higher during inspiration in order to open the alveoli
BiPAP indicaation
atelectasis
OSA
BiPAP advantages over CPAP (2)
easier exhalation
reduces air trapping
difference between BiPAP and airway pressure release ventilation
airway pressure release ventilation intermittently stops to allow for complete exhalation
what 2 vent modes provide constant CPAP?
BiPAP
airway pressure release vent
inverse ratio ventilation (IRV)
vent reverses the inspiratory and expiratory times
(I>E)
IRV advantage
longer inspiratory time
incr FRC
IRV disadvantage
incomplete exhalation
- auto-PEEP
does not allow spontaneous breathing
High-Frequency Positive Pressure Ventilation (HFPPV)
small tidal volumes
60-120 breaths/min
High-Frequency Jet ventilation
small airway cannula
120-600 breaths/min
High-Frequency Oscillation
600-3000 breaths/min
autoflow ventilation is an adjunct to _______
volume controlled ventilation modes
autoflow advantages
-delivers set tidal volume at lowest possible PiP
-decr peak airway pressures
-pt can breath spontaneous at any time
autoflow uses ______ flow to decrease peak airway pressures
decelerating flow
the vent is more or less likely to breath against the pts expiration during autoflow?
less likely
volume control inspiratory FLOW waveform
square
volume control inspiratory PRESSURE waveform
peak pressures + plateau pressure
autoflow inspiratory FLOW waveform
decelerating
autoflow inspiratory PRESSURE waveform
square
active scavenging
hooked up to hospital suctioning system
active scavenging disadvantage
vacuum system requires $$$ pipework
needle valve requires adjustment
passive scavenging advantages
inexpensive
simple
passive scavenging disadvantages
impractical in some facilities
passive scavenging waste gases can be ducted out of
open window
pipe to outside wall
extractor fan vented to exterior
active scavenging should be set to
10-15 L/min
charcoal canister advantages
no setup cost
mobile
charcoal canister disadvantage
continuing replacement cost
does not remove N2O