Mod 5 Invasive Vent Modes and Settings Flashcards
Mechanical breaths modes only?
Controlled -> mandatory breaths only
CMV -> Mandatory + Assisted breaths
Combination breath modes?
IMV -> Mandatory + spontaneous
SIMV -> Mandatory + assisted + spontaneous breaths
Spontaneous breath modes only?
CSV
Continuous Mandatory Ventilation (CMV)
Delivers what kind of breath?
CMV is also known as A/C (assist/control ventilation)
SO…Mandatory and assisted breaths.
-guarantees a min rate.
Indications for CMV?
Patient requires full vent. support (FVS)
-high WOB
-crisis management
Ventilators: What mode requires a sensitivity set?
Any mod that has patient triggering as an option
Ventilators:
Advantages of CMV?
Pt can set rate
Guarantees:
-min number of mandatory breaths/min
-volume or pressure delivered (pt or time triggered)
-syncs w/pt effort
Ventilators:
Cons to CMV?
May cause/worsen auto-peep
Resp. alkalosis (if pt’s rate is high)
increased WOB if sensitive not set right
poor tolerance in non-sedated
possible resp. muscle atrophy
Ventilators:
what is synchronized Intermittent Mandatory Ventilation (SIMV)?
-Pt has a set rate and number of mechanical breaths.
IMV vs CMV?
IMV Patient can take breaths in between set breaths?
I:E ratio calculation
What vent setting is present lets you know you’re in volume control?
Flow
What setting is present that lets you know you’re in IMV vs CMV?
Pressure support.
Volume vs Pressure: Compliance equation
Compliance = Delta Volume / Delta Pressure
Compliance = Delta Volume / Delta Pressure
What does the compliance equation tell us?
Depending on which delta you set (control), the other variable depends on the compliance is.
If you set a patient in volume control [VC]; which values are constant and which values are targets?
Volume is constant.
Depending on the volume; the pressure that’s required to reach that volume is gonna vary
In pressure control; which variable do we set (constant) and which is the target?
Pressure is constant
Volume is variable (depending on compliance)
In volume control; which variable do you set and what does the vent do?
The vent adjusts pressure to ensure proper pressure is achieved
More P -> more flow -> More Vt (and in the inverse)
In pressure control; what variables do you set?
Respiratory rate [Frequent], FiO2, PEEP
AND
inspiratory pressure and time
Define: Dual Mode Ventilation: Pressure regulated volume control (PRVC)
Operates like pressure control but ensuring a set volume is achieved; takes feedback and makes adjustments based on that
True or False:
Pressure regulated volume [PRVC] adjustments are made in real time according to spontaneous breaths
False
Adjustments are made slowly overtime
In PRVC; what are the advantages of setting a target volume rather than a fixed volume?
TLDR: Gradual adjustments until it reaches and can operate at target volume based on pt compliance
Advantage: when patients compliance improves; the vent will adjust and reduce pressures so the pt can breath (can ween the inspiratory pressure)
-Can operate a pressure control but ensures that you are getting enough volume.
Auto PEEP: How can you recognize it?
Expiratory flow does not return to 0 after pause or when the next breath is given
Auto PEEP: purpose in use
Increase FRC, dilate the airways by manipulating the I : E ratio (increasing expiratory time)
Auto PEEP: How to measure auto PEEP?
Expiratory hold; measuring expiratory pressures
What is intrinsic PEEP
amount set above the PEEP?
How do you prevent over distension of airways?
Keep Pplat under 30
How do you calculate TCT?
60/rate
R -> PIP -> V
C -> Pat -> o V
What mode is pt/time triggered, pressure limited, and time cycled?
Pressure control
What mode is pt/time triggered, flow limited, and volume cycled?
Volume control
What mode is pt triggered, pressure limited, and flow cycled (insp flow declined to a certain level)
Pressure support
What mode is pt/time triggered, pressure adaptive variable limited, and time adaptive cycled?
PC-CMV Adapative
Explain pressure control in terms of trigger, limited, and cycle
Pt/time triggered
pressure limited
time cycled
Explain volume control (w/o inspiratory pause) in terms of trigger, limited, and cycle
pt/time triggered
flow limited
volume cycled
Explain volume control (w/inspiratory pause) in terms of trigger, limited, and cycle
pt/time triggered
volume/flow limited
time cycled
What is pressure support in terms of trigger, limited by what, and cycled by what?
pt triggered
pressure limited
flow cycled
What is VC-CMV control variable (w/inspiratory hold)?
volume/flow
What is PC-CMV control variable?
Pressure
What is PC-CMV Adaptive control variable?
Pressure
A flow-cycled breath is considered to be cycled by what?
Patient cycled
What are assisted breaths?
Triggered by Pt, but the vent controls the rest of the breath
What is the difference between a mandatory breath and a assisted breath?
Assisted breath is pt triggered
How do you calculate compliance?
C = Volume/ (Pplat - PEEP)
How do you calculate resistance?
R = (PIP-Pplat) / flow
How do you calculate time constant?
TC = R x C
Why are some complications of increasing of PEEP risky?
Barotrauma aka overdistension of lungs
As PEEP is increased, the volume of air delivered to the lungs during each breath (VT) may need to be decreased to maintain safe levels of lung inflation.
What affect does an increase of PEEP have on RR?
**Increasing PEEP can decrease patient’s respiratory rate. **
Because
Higher pressure in lungs by PEEP makes it easier to exhale, which can lead to a slower respiratory rate.
How does increasing PEEP affect the I:E ratio?
Increasing PEEP can increase Ti
Because:
Higher pressure in lungs by PEEP make it harder for air flow in/out of lungs; requiring a longer Ti time to achieve adequate ventilation
Why ma you need to FiO2 when PEEP increases?
PEEP decreases amount of fraction of O2 delivered to pt, conversly the O2 reaching the alveoli. [hypoxemia]
Solution:
increase FiO2
How can you increase Vt?
1. Increase the respiratory rate:
-By increasing the number of breaths per minute, more air is delivered to the lungs over the course of a minute.
2. Increase the inspiratory flow rate:
-This can help deliver more air to the lungs in a shorter period of time, thereby increasing the tidal volume.
When there is an increase in lung compliance, what does this mean for airway pressure/flow?
Lung are easier to inflate: meaning less pressure is required to achieve adequate ventilation.
