AVEA Enhanced Pulmonary Mechanics

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AVEA Enhanced Pulmonary Mechanics
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Advanced SettingsUser Interface Module
Advanced Settings Feature
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Accessing Advanced Features
Press Adv Settings hard key on left side panel
of the Avea monitor to access the Advanced
Settings Window
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Advanced Settings Window
Yellow triangle indicates this parameter has
Advanced Settings
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Activating an Advanced Setting
Press the desired parameter. The parameter will
then be high-lighted with a blue background.
The Advanced Settings features will then appear
in the window above for the parameter
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Advanced Settings

• Universal Features
• Sensitivity Pressure Support

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Sensitivity Flow Pressure
Flow Trigger Advanced Settings
Bias Flow Pressure Trigger Sensitivity
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Sensitivity

• Bias Flow
• Bias Flow enables Flow Triggering
• To have adequate Flow Triggering, the Bias Flow
  should be set 0.5 liters above the Flow Trigger
  setting
• Example Bias Flow set at 2.0 litres, Flow
  Trigger should be set no higher than 1.5 litres
• Pressure Trigger
• The Avea has both a pressure and a flow trigger
  active at the same time. Whichever signal (flow
  or pressure) is triggered first, the ventilator
  will then cycle into inspiration

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Pressure Support Ventilation
PSV Setting has 4 Advanced Settings
Max Inspiratory Time
Volume Limit
Rise Time
Flow Cycle
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Pressure Support Ventilation

• Volume Limit
• Every pressure type breath on the Avea has
  Volume Limit as an Advanced Setting feature
• The clinician can enter a maximum volume limit.
  Once the ventilator has reached this limit during
  the delivery of the breath, it will then cycle
  the breath to exhalation using volume as the
  cycle criteria
• When the volume limit is reached, a visual
  display appears in the alarm area. The display
  remains illuminated as long as the volume limit
  is active
• PSV Rise Time
• Setting range is from 1 to 9, 1 being fastest and
  9 slowest.
• Allows the clinician to adjust the speed at which
  flow is delivered to the patient during a
  Pressure Support breath

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Pressure Support Ventilation

• PSV Flow Cycle
• The Flow Cycle works as a percentage of the peak
  flow of the PSV breath
• The Flow Cycle can be set in increments of 5 up
  to 45
• Example If the flow cycle is set at 10 and the
  peak flow for the PSV breath is 60 lpm, the
  breath will cycle when the decelerating
  inspiratory flow curve decays to 6 lpm
• PSV Tmax
• The PSV Maximum Inspiratory Time setting allows
  for an adjustable back up inspiratory time
  setting in circumstances where flow cycling is
  unreliable (i.e. endotracheal tube leaks)
• PSV Tmax should be set at 1.5-2 X the set
  Inspiratory Time for Control breaths
• The PSV Tmax is adjustable from 0.2 to 5.0
  seconds

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Advanced Settings

• Pressure Control Ventilation - PCV

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PCV - Pressure Control
Inspiratory Pressure
Inspiratory Time
Flow Trigger
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Inspiratory Pressure in PCV
Touch Insp Pres and these settings become
available
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Advanced Settings Inspiratory Pressure in PCV

• Mach Vol (Machine Volume)
• This feature allows the clinician to set a target
  tidal volume during a Pressure Control breath
• When Machine Volume is active, the Mach Vol
  icon appears in the modes display window

Machine Volume icon
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Machine Volume

• Is a Dual Control Mode Ventilator delivers
  Volume Controlled Flow signal and Pressure
  Control signal to gas delivery system
  simultaneously.
• Sets the minimum tidal volume delivered from the
  ventilator in a pressure control breath.
• Always used with the time cycling criterion in
  pressure control ventilation.
• Circuit compliance compensated in adult and
  pediatric applications.

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Machine Volume

• Allows for the maintenance of traditional Volume
  Control Ventilation while allowing the ventilator
  to vary peak flow to meet the patients
  inspiratory flow demands

• Incorporates a decelerating/ variable inspiratory
  flow waveform
• Can be thought of as a variable flow-volume
  ventilation

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Machine Volume

• Ventilator calculates the decelerating
  inspiratory flow required to deliver the Machine
  Volume (Minimum Tidal Volume) in the set
  inspiratory time.
• When Peak Flow decelerates to this calculated
  peak inspiratory flow
• If Machine Volume has not been delivered
• transition to a continuous flow until the Machine
  Volume has been delivered
• Inspiratory Time will remain constant
• maximum Peak Inspiratory Pressure is determined
  by the High Peak Pressure alarm setting
• If the Machine Volume is met or exceeded during
  delivery of the pressure control breath, the
  ventilator will complete the breath as a normal
  Pressure Control breath.

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Pressure Control- Volume Control Transition
Pressure is increased within the breath
The constant, square wave flow continues until
the pre-set tidal volume is delivered
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Pressure Control Adjustments with Machine Volume
Guarantee

• Pressure Control
• Decreased
• Compliance
• Lung
• Chest Wall
• Neuromuscular Blockers
• Increased AW Resistance
• Mucous
• Bonchospasm

• Pressure Control
• Increased
• Compliance
• Lung
• Chest Wall
• Spontaneous Breathing
• Decreased AW Resistance
• Post Suctioning
• Post Bronchodilators

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Machine Volume
Note Inspiratory Pressure set at zero, breath is
decelerating flow pressure controlled breath.
(Set Mach Volume 350cc) Inspiratory time is
constant
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Machine Volume
Note transitions in flow between Pressure Control
and Volume Control flow waveforms
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Machine Volume Vs. PRVC
Machine Volume can respond to changes in
compliance within 2-4 msec. PRVC will update on
next breath.
Compliance decreases ventilator responds within
the breath
Compliance increases ventilator responds within
the breath
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Inspiratory Pressure in PCV

• Vol Limit (Volume Limit)
• This feature allows the clinician to set a
  maximum volume limit that cannot be exceeded
  during a Pressure Control breath
• When the volume limit is reached, a visual
  display appears in the alarm area. The display
  remains illuminated as long as the volume limit
  is active
• Insp Rise (Inspiratory Rise Time)
• Setting range from 1 to 9, 1 being fastest and 9
  slowest.
• Allows the clinician to adjust the speed at which
  flow is delivered to the patient during a
  Pressure Control breath

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Volume Limit

• Active in
• Pressure,
• PRVC
• Vsync
• TCPL
• PSV breaths only.
• Neonatal applications Volume LimitTM requires the
  use of a wye flow sensor.
• If a proximal flow sensor is used
• Volume Limit is activated by the inspiratory
  tidal volume measured by the wye flow sensor.

• If Volume Limit threshold has been reached
• Alarm status indicator will change to yellow and
  display the words Volume Limit.
• Cannot be reset until the ventilator has
  delivered a breath, which does not meet the
  Volume Limit threshold.
• To reset the alarm status window use the
  alarm-reset button
• Do not use with leaky ET tube

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Volume limit with Neonatal Flow Sensor
2 KG
Inspiratory VT limit 16 ml

8 cc/kg
Volume limit can be used in conjunction with
Machine volume to allow volume bracketing in
Pressure Control. Machine volume is the minimum
volume guarantee and Volume Limit will terminate
the breath based on a maximum inspiratory tidal
volume threshold. When used with only PCV, as
compliance improves, so will volume. Patient will
be protected from inadvertent volutrauma. Volume
Limit may limit gas flow during hiccups or during
increased flow demands of the patient.
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Inspiratory Time in PCV
Flow Cycle is the only Advanced Setting feature
for Inspiratory Time.
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Inspiratory Time in PCV

• Flow Cycle
• In addition to time cycling in PCV, the Avea
  allows the clinician the ability to add flow
  cycling to the inspiratory cycle criteria of the
  PCV breath
• The Flow Cycle works as a percentage of the peak
  flow of the PCV breath (mimicking a Pressure
  Support Breath)
• When a Flow Cycle percentage is set, the PCV
  breath can either be cycled into expiration by
  the percentage of Flow Cycle or Inspiratory Time
  depending on which criteria is met first

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Flow Cycle

• The default setting is 0 (off)
• Can be set in increments of 5 to 45

• Flow cycle can be more comfortable for
  spontaneously breathing patients
• It can reduce mean airway pressure and VT

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Flow Cycle

• Allows patient to determine their own I- time by
  terminating the breath once a certain percentage
  of the peak inspiratory flow is met
• May improve preload and eliminate V/Q mismatching
  
• Improves patient/ventilator dsy-synchrony
• May tremendously improve oxygenation and
  ventilation in spontaneously breathing patients

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Expiratory Flow Cycling
V
T
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Fixed Inspiratory Time No Flow Cycle
Flow Cycle On
Flow Cycled Breath
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Flow Cycle
Volume Cycled Breath
Flow Cycled Breath
If Flow Cycle is set with Machine Volume the
breath will not Flow Cycle unless the Machine
Volume (Minimum Tidal Volume) has been delivered
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Patient Comfort

• Dial in a Flow Cycle
• May apply Flow Cycle transiently to measure pts
  true I time and set IT accordingly
• Flow Cycling can only occur if target tidal
  volume has been reached in PRVC and Machine
  Volume
• Should only be used with patients that have low
  FiO2 requirements because by limiting IT Mean
  Airway Pressure may be affected

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Breath Termination Hierarchy
Alarm Supercedes all other criteria
Volume Limit If set, supercedes all lesser
criteria
Flow Cycle In volume targeted and controlled
modes only after set volume is achieved
Time / Volume Cycled If no other criteria
intercede
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Advanced Settings

• Volume Control Ventilation - VCV

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VCV - Volume Control
Volume Peak Flow PSV
Flow Trigger
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Volume Parameter in VCV
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Volume Parameter in VCV
When Vsync is selected, Volume Limit becomes
apparent and the Vsync icon appears on screen.
0Off 1On
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Advanced SettingsVsync

• Vsync operates similar to PRVC
• Flow is only difference
• Set in Vsync
• Automatic in PRVC
• The maximum step change between two consecutive
  breaths is 3 cm H2O.

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Volume Limit

• This feature allows the clinician to set a
  maximum volume limit that cannot be exceeded
  during a Vsync breath.
• When the volume limit is reached, a visual
  display appears in the alarm area. The display
  remains illuminated as long as the volume limit
  is active

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Advanced SettingsVolume Parameter in VCV

• Vsync Rise Time
• Setting range from 1 to 9, 1 being fastest and 9
  slowest.
• With Vsync active, this control allows the
  clinician to adjust the speed at which flow is
  delivered to the patient.
• Sigh
• A sigh volume breath is delivered every 100th
  breath in place of the next normal volume breath.
• The sigh volume breath is 1.5 times the set tidal
  volume

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Advanced SettingsPeak Flow in VCV
Waveform Type
Demand Flow On/Off
0 Square
1 Ramp
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Intra-Breath Demand Flow

• Peak Inspiratory Pressure (Ppeak) every 2
  milliseconds throughout the breath cycle
• Virtual Pressure Support Target of the greater
  of
• PEEP 2 cmH2O or
• Ppeak 2 cmH2O
• Maximum PEEP x 2
• Ppeak decrease by 2 cmH2O
• switch over to Pressure Support at virtual PSV
  Target.
• Once Tidal volume has been delivered
• looks at the inspiratory flow
• Inspiratory Flow gt set peak flow
• flow cycled at 25 of peak inspiratory flow
• Inspiratory Flow set flow
• ends as Volume Control breath

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Intra-Breath Demand Flow in VCV
Note augmented flow to meet patients inspiratory
demand. Demand ends before set volume has been
delivered.
Demand continues through end of breath. Breath
is FLOW CYCLED at 25 of PIFR.
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Intra-Breath Demand Flow ON / OFF
Double cycling in periods of high demand
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PSV Flow Trigger in VCV
These Advanced Settings are the same for all
modes and types of ventilation
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Advanced Settings

• Pressure Regulated Volume Control - PRVC

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PRVC Pressure Regulated Volume Control
Flow Trigger
Inspiratory Time
Volume
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Volume Parameter in PRVC
Similar settings to PCV since PRVC is a hybrid of
PCV
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PRVC / Vsync

• Logic controlled Volume TARGETED breath
• Decelerating flow, VC test breath with a 40 msec
  pause
• End inspiratory pressure is Target Pressure for
  the first pressure control breath
• Subsequent breaths are delivered as pressure
  control breaths based on the dynamic compliance
  of the previous breath.
• Inspiratory pressure is adjusted automatically by
  the ventilator to maintain the target volume.
• Maximum step change between two consecutive
  breaths is 3 cmH2O.
• Maximum tidal volume delivered in a single breath
  is determined by the Volume Limit setting.
• Vsync NOTE
• The Peak Flow control sets the flow rate, which
  is used by the ventilator for the test breath
  only. The ventilator uses the Peak Flow setting
  and Inspiratory Pause to determine the maximum
  inspiratory time during Vsync ventilation.
• Flow Cycling can only occur if target tidal
  volume has been reached

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PRVC / Vsync

• This test breath sequence is initiated in the
  event any of the following occur
• Entering the Mode (PRVC or Vsync)
• Changing the set tidal volume while in PRVC or
  Vsync
• Reaching the Volume Limit setting
• Delivered tidal volume gt 1.5 times the set volume
• Flow termination of the test breath
• Intrabreath demand system is active for all test
  breaths
• Exiting Standby
• Activation of any of the following alarms
• High Peak Pressure Alarm
• Low Peak Alarm
• Low PEEP Alarm
• Patient Circuit Disconnect Alarm
• I-Time Limit
• IE Limit
• Flow Cycling can only occur if target tidal
  volume has been reached

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Advanced Settings

• Airway Pressure Release Ventilation - APRV

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APRV

• Patient breathes spontaneously at a CPAP level
• Periodically released to a lower CPAP level to
  flush CO2 from the FRC

P
Question What two features would make this
type of ventilation better?
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APRV Airway Pressure Release Ventilation
Answer Synchronize the changes and add
PSV Thats what these Advanced Settings do.
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Advanced SettingsTime High in APRV
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APRV

• Allows spontaneous breathing over a high mean
  airway pressure.
• High mean airway pressure may improve lung
  recruitment.
• Pressure support available .
• Apnea back-up parameters available.

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APRVAdvanced settings

• Time high sync period-allows the operator to
  allow a period in which the ventilator will
  synchronize (during expiration) from high to low
  pressure phase.
• Adjustable from 0-50 of Time high.
• Time high PSV-on or off-allows the user to have
  pressure support on or off during the time high
  phase.
• Time low sync- allows the operator to allow a
  period in which the ventilator will synchronize
  (during inspiration) from 0-50
• Adjustable from 0-50 of Time high

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APRVProposed Benefits

• 1. Lower Paw for a given tidal volume compared
• with volume-targeted modes, e.g., AC, SIMV
• 2. Lower minute ventilation, i.e., less dead
  space
• ventilation
• 3. Limited adverse effects on cardio-circulatory
• function
• 4. Spontaneous breathing possible throughout
• entire ventilatory cycle
• 5. Decreased sedation use
• 6. Near elimination of neuromuscular blockade

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APRV
Spontaneous breaths
Pressure
Time High
Time Low
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Advanced Settings Time High in APRV

• Time High Sync
• Synchronizes transition from Pressure High to
  Pressure Low
• Occurs with the first end of inspiration detected
  after the Time High Sync window opens.
• The Time High Sync window is adjustable from 0
  to 50, in 5 increments of set Time High.
• The default setting for Time High Sync is 0
  (off)

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Advanced Settings Time High in APRV

• Time High PSV
• Time High PSV is either turned on (position 1) or
  off (position 0)
• The PSV is delivered above the current phase
  baseline pressure.
• If Time High PSV is activated as Time High
  Advanced Setting, the ventilator will deliver
  the same PSV level for both Pressure High and
  Pressure Low.
• Example If Plow 5cmH2O and Phigh 25cmH2O, then
  a PSV breath set at 5 cmH2O will result in a Plow
  increase to 10cmH2O and Phigh increase to
  30cmH2O

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Advanced SettingsTime Low in APRV
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Advanced SettingsTime Low in APRV

• Time Low Sync
• The ventilator synchronizes the change from
  Pressure Low to Pressure High with the detection
  of inspiratory flow or the first inspiratory
  effort detected within the Time Low Sync
  window.
• The Time Low Sync window is adjustable from 0
  to 50, in 5 increments of set Time Low.
• The default setting for Time Low is 0 (off)

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Synchronization Window
Gives a range of possible I-times if Sync is
activated

• Actual Time High or Time Low can change if Sync
  is activated
• Depends on when the patient triggers to go from
  High to Low or Low to High

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PSV Flow Trigger in APRV
Both PSV Flow Trigger Advanced Settings in VCV
function as previously discussed on earlier
slides
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Automatic Airway Compensation (AAC)

• AAC when applied, will supplement spontaneous
  pressure support or or pressure control flow
  cycled breaths based on calculated endotracheal
  tube resistance.
• Has no role in other pressure control or volume
  breath types.
• To activate, select AAC On and dial in tube
  size and length. An indicator
  saying AAC will appear in the mode bar.

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How Does Tube Compensation Work?

• Positive pressure added based on the inspired
  flow and tube curvature, diameter, and length
• Patient doesnt have to experience the resistive
  work due to the artificial airway

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AAC

• Calculation based on
• ETT Size
• 2.0 to 10.0
• Length
• flow
• pharyngeal curvature
• FiO2 / gas density
• transitions from turbulent to laminar flow  
• Only ventilator with AAC available for controlled
  breaths

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AAC

•  
• (length) x (viscosity) (radius4) 
• This equation is used during periods of
  laminar flow where resistance is primarily
  determined by gas viscosity.
•  
•   (density 0.75) x (viscosity .025) x (flow
  1.75) x (length)
  (radius 4.75)
• This equation is used during periods of
  turbulent flow where resistance is primarily
  determined by gas density.

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What The Ventilator Circuit Sees
Circuit Pressure

• Flow triggering can be effective in minimizing
  imposed work

Paw
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What The Carina Sees
Circuit pressure
Lower pressure at the carina
Paw
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What the Carina Sees
Higher circuit pressure

• AAC adds appropriate pressure to keep carina
  pressure at preset inspiratory pressure

No decrease in pressure at carina
Paw
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Considerations when using AAC

• Monitor pressure support level to achieve desired
  volumes. Supported breaths may be augmented above
  pressure support, so less pressure support may be
  needed.
• Compensatory support varies with many factors,
  and will vary with patient effort and other
  factors.
• Monitor volumes and pressures carefully, with
  special considerations with neonates.

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Set-up for Patient Use (cont)

• Automatic Airway Compensation-suggested
• reading
• Wrigge H, Zinerling J, Hering R,Swafenberg N,
  Stuber F, et al, Cardiopulmonary effects of
  automatic tubing compensation during airway
  pressure release ventilation in patients with
  acute lung injury Anesthesia 2001 Aug95(2)382-9
• Guttmann J, Haberthur C, Mols G.Related
  Articles
• Automatic tube compensation.Respir Care Clin N
  Am. 2001
• Sep7(3)475-501

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AutoPEEP Airway
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AutoPEEP Airway
AutoPEEPaw is the airway pressure at the end of
exhalation immediately prior to the beginning of
the next mandatory inspiration.
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AutoPEEP Airway Timing
The ventilator will establish the AutoPEEP
measurement when the system pressure reaches
equilibration, at the next mandatory breath
interval or 6 seconds whichever is shorter.
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AutoPEEP Airway Gas Trapping
Normal 0 cm H2O above the applied
PEEP Note Requires a passive patient and a
cuffed endotracheal tube. Occurs when either
insufficient expiratory time is present or in
dynamic flow limitation conditions such as asthma
or severe COPD. This results in gas trapping in
the lungs.
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MIP / P100 Maneuver
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MIP Maneuver
The MIP (Maximum Inspiratory Pressure) / P100
maneuver measures the negative deflection in the
pressure tracing during the patients active
effort to demand a breath.
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MIP Maneuver
Maximum Inspiratory Pressure (MIP), is the
maximum negative airway pressure that is achieved
by the patient, during an expiratory hold
maneuver.
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MIP Maneuver
Normal Adults lt -70 to -100 cm H2O
Pediatrics lt -20 to -100 cm
H2O Readiness for
extubation lt -20 cm H2O Note
Patient effort variable. Indicator of
inspiratory muscle strength. Useful in weaning
and progression of neuromuscular disease. Will be
decreased in conditions such as kyphoscoliosis,
advanced age, COPD and neuromuscular disease.
.
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P100 Maneuver
Respiratory Drive (P100), is the negative
pressure that occurs 100 ms after an inspiratory
effort has been detected.
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P100 Maneuver
Normal -1 to -4 cm H2O Adults
-0.5 to -4 cm H2O Pediatrics Note T
he pressure that occurs 100 milliseconds (ms)
after the onset of inspiration while the
inspiratory valve remains closed. Because it
normally takes at least 300 ms for the patient to
become aware of the occluded airway this is a
good test of the respiratory center output. There
is no change in lung volume or airflow during
this initial 300 ms, therefore abnormalities in
lung mechanics have no effect on the
measurement. Values in excess of -5 cm H2O may
indicate a high respiratory drive that may result
in increased work of breathing and subsequent
fatigue.