basic ventilatory modes
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BASIC MODES OF MECHANICAL VENTILATION
Mazen Kherallah, MD, FCCP
POINTS OF DISCUSSIONS
Advanced Basics: Flow and Time Limit and cycling Rise Time Volume vs Pressure Control
Mandatory Modes of Ventilation Controlled Mandatory Ventilation (CMV or IPPV)
Triggered Modes of Ventilation Continuous Positive Airway Pressure (CPAP) Pressure Support Ventilation (PSV)
Hybrid Modes of Ventilation Assist Control Mode (A/C) Synchronized Intermittent Mandatory Ventilation (SIMV)
ADVANCED BASICS
RESPIRATORY CYCLET
rans
ition
=In
spira
tory
Cyc
ling
Transition=Expiratory Cycling
Inspiration
Expiration
ExpInsp
RELATIONSHIP BETWEEN TIDAL VOLUME, INSPIRATORY TIME AND FLOW
VT 1
Ti a
VT 2
VT 3
Time
Volume
Flow= 30 L/min
Flow= 15 L/min
Flow= 37.5 L/min
ExpExpInspInspInsp
RELATIONSHIP BETWEEN TIDAL VOLUME, INSPIRATORY TIME AND FLOW
VT 1
Ti a
Time
Volume
Ti b Ti c
Flow= 30 L/min
Flow= 20 L/min
Flow= 60 L/min
PRESSURE LIMITED BREATH
Time
Volume
Pressure Limit
EXPIRATORY FLOW CYCLING
Time
Flow
50%
100%
Flow Cycling
RISE TIME
Time
Flow
Pressure
Volume
TI TE
MANDATORY, SPONTANEOUS AND TRIGGERED INSPIRATORY CYCLING
M
S
Tsynch
M M
M
MM
M
M
S
M
Tsupp Tsupp
Tsupp Tsupp
Tsupp
Tsupp
S
VOLUME CONTROLLED INFLATION
Time
Flow
Pressure
Volume
TI TE
Tidal Volume
If compliance decreases the pressure increases to maintain the same Vt
11 22 33 44 55 66
SECSEC
11 22 33 44 55 66
PPawaw
cmHcmH2200
5050
-20-20
120120
120120
SECSEC
INSPINSP
EXHEXH
FlowFlowL/minL/min
VOLUME CONTROL BREATHS
Decreased Compliance
VOLUME CONTROL WITH END-INSPIRATORY PAUSE
Time
Flow
Pressure
Volume
TI TE
Tidal Volume
End Inspiratory Pause
PRESSURE CONTROLLED INFLATION
Time
Flow
Pressure
Volume
TI TE
Tidal Volume
Rise Time
Peak Inspiratory Flow
Inspiration Expiration
0 1
20
00 1 2
3
-3
0
20
021
20
00 1 2
3
-3
0
20
02
Inspiration Expiration
Volume/Flow Control Pressure Volume/Flow Control Pressure ControlControl
Time (s) Time (s)
PawPaw
Pressure
Volume
Flow
TRIGGERED MODES OF VENTILATIONCPAP and PSVV
SPONTANEOUS BREATHINGSPONTANEOUS BREATHING
Time (sec)Time (sec)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
CONTINUOUS POSITIVE AIRWAY PRESSURE(CPAP)
CONTINUOUS POSITIVE AIRWAY PRESSURE(CPAP)
Time (sec)Time (sec)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
CPAP Level
PRESSURE SUPPORT VENTILATION(PSV) PRESSURE SUPPORT VENTILATION(PSV)
Time (sec)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
Set PS Level
Flow Cycling
Better Efforts
Longer Inspiration
Patient Triggered, Flow Cycled, Pressure limited Mode
CPAP+PSVCPAP+PSV
Time (sec)Time (sec)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
Set PS Level
Flow Cycling
Patient Triggered, Flow Cycled, Pressure limited Mode
CPAP Level
TRIGGERED MODES OF VENTILATIONPRESSURE SUPPORT VENTILATION
Control Trigger Limit Target Cycle
Pressure Patient Pressure Flow
Patient Triggered Flow Cycled Ventilation
PRESSURE OR VOLUME-TARGETED VENTILATION
Full to partial ventilatory support Augments the patients spontaneous VT Decreases the patient’s spontaneous
respiratory rate Decreases patient WOB by overcoming
the resistance of the artificial airway, vent circuit and demand valves
Allows patient control of TI, Vm I, f and VT
Set peak pressure Prevents respiratory muscle atrophy Facilitates weaning Improves patient comfort and reduces
need for sedation May be applied in any mode that allows
spontaneous breathing, e.g., VC-SIMV, PC-SIMV
Requires consistent spontaneous ventilation
Patients in stand-alone mode should have back-up ventilation
VT variable and dependant on lung characteristics and synchrony
Low exhaled VE
Fatigue and tachypnea if PS level is set too low
Advantages Disadvantages
MANDATORY MODES OF VENTILATIONCMV or IPPV
MANDATORY MODES OF VENTILATIONCMV
Control Trigger Limit Target Cycle
PressureOr
Volume
Time Time
Time Triggered Time Cycled Ventilation
CONTROL MODE (PRESSURE-TARGETED VENTILATION)CONTROL MODE (PRESSURE-TARGETED VENTILATION)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
Time Triggered, Pressure Limited, Time Cycled Ventilation Time (sec)
Time CyclingSet PC Level
CONTROL MODE(VOLUME-TARGETED VENTILATION)CONTROL MODE(VOLUME-TARGETED VENTILATION)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
Time Triggered, Flow Limited, Volume Cycled Ventilation Time (sec)
Preset VT
Volume Cycling
Time Cycling
Dependent onCL & Raw
PRESSURE OR VOLUME-TARGETED VENTILATION
Decreases the work of breathing (WOB)
Helps maintain a normal PaCO2
Not able to assist the ventilator
Advantages Disadvantages
HYBRID MODES OF VENTILATIONSIMV and A/C
HYBRID MODES OF VENTILATIONA/C
Control Trigger Limit Target Cycle
PressureOr
Volume
Time Or
Patient
Time
Time or PatientTriggered Time Cycled Ventilation
ASSISTED MODE(VOLUME-TARGETED VENTILATION)ASSISTED MODE(VOLUME-TARGETED VENTILATION)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
Patient Triggered, Flow limited, Volume Cycled Ventilation Time (sec)
Preset peak Flow
Time Cycling
ASSISTED MODE (PRESSURE-TARGETED VENTILATION)ASSISTED MODE (PRESSURE-TARGETED VENTILATION)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
Patient Triggered, Pressure Limited, Time Cycled Ventilation
Time (sec)
Time CyclingSet PC Level
PRESSURE OR VOLUME-TARGETED VENTILATION
Decreases the work of breathing (WOB)
Allows patients to regulate respiratory rate
Helps maintain a normal PaCO2
Alveolar hyperventilation
Advantages Disadvantages
HYBRID MODES OF VENTILATIONSIMV/PS
Breath Type
Control
Trigger
Limit Cycle
Mandatory PressureOr
Volume
Time Or
Patient
Time
Spontaneous
Pressure Patient Pressure Flow
SIMV(VOLUME TARGETED VENTILATION)SIMV(VOLUME TARGETED VENTILATION)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
Spontaneous Breaths
M M M
Time (sec)
SIMV+PS(VOLUME TARGETED VENTILATION)SIMV+PS(VOLUME TARGETED VENTILATION)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
MTsuppTsynch
Set PS Level
Flow-cycled
Time (sec)
SIMV + PS (PRESSURE-TARGETED VENTILATION)SIMV + PS (PRESSURE-TARGETED VENTILATION)
Flow(L/m)
Pressure(cm H2O)
Volume(mL)
Tsupp
Tsynch
Time Cycled Flow-cycled
Tsynch
Set PC Level
Set PS Level
Time (sec)
HYBRID MODE VENTILATION: SUPPRESSION
Time (sec)Time (sec)
M Tsupp MM Tsupp
M M
Tsupp Tsupp
HYBRID MODE VENTILATION: SYNCHRONIZATION(SIMV+PSV)
HYBRID MODE VENTILATION: SYNCHRONIZATION(SIMV+PSV)
Time (sec)Time (sec)
Flow(L/m)
Pressure(cm H2O)
Cycles
Triggered window for supported breaths
Triggered window for synchronized breaths
Mandatory Cycle Time
M Tsupp TsynchM Tsynch Tsupp
SIMV
Maintains respiratory muscle strength by avoiding muscle atrophy
Decreases mean airway pressure
Facilitates ventilator discontinuation – “weaning”!
When used for weaning, may be done too quickly and cause muscle fatigue
Mechanical rate and spontaneous rate may asynchronous causing “stacking” May cause
barotrauma or volutrauma
Advantages Disadvantages
ALL MODES TABLES
Mandatory Modes of Ventilations
Mandatory breaths
Inspiratory cycling Time Time Time Time
Control Volume Volume Volume (Pressure)
Target/Limit - Pressure-limitedVolume-targeted
Feeadback - - Intra-breath Inter-breath
Expiratory cycling Time Time Time Time
Triggered Breaths
Types None None None None
Supported Breaths
Control - - - -
Target - - - -
Feedback - - - -
Expiratory Cycling - - - -
Spontaneous Breaths
During mandatory inspirationNot accommodated
Not accommodated
Not accommodated
Accommodated
OtherwiseNot accommodated
AccommodatedNot accommodated
Accommodated
Synonyms
IPPV (Draeger)Controlled Mandatory Ventilation
Intermittent Mandatory Ventilation
IPPV (Draeger): trigger off, autoflow off
IPPV (Draeger): trigger off, autoflow on
Triggered Modes of Ventilations
Mandatory breaths
Inspiratory cycling - - -
Control - - -
Target/Limit - - -
Feeadback - - -
Expiratory cycling - - -
Triggered Breaths
Types Supported breaths Supported breaths Supported breaths
Supported Breaths
Control Pressure (Pressure) (Pressure)
Target -- Volume-targeted Flow and Volume
Feedback -- Inter-breath Intra-breath
Expiratory Cycling Flow Flow Flow
Spontaneous Breaths
During mandatory inspiration
- - -
Otherwise - - -
Synonyms
Assisted Spontaneus Breathing (Draeger)Spontaneous Mode (Hamilton, Puritan Bennet)Pressure Support (MaquetPressure Support Ventilation (Viasys)CPAP (Respironics)
Volume Support (Maquet, Puritan-Bennett)
Propotional Assist Ventilation, Proportional Pressure Suport (Draeger)Propotional Assist Ventilation Plus (Puritan-Bennet)
Hybrid Mode: Assist Control
Mandatory breaths
Inspiratory cycling Time or trigger Time or trigger Time or trigger
Control Volume Pressure (Pressure)
Target/Limit - - Volume-targeted
Feeadback - - Inter-breath
Expiratory cycling Time Time Time
Triggered Breaths
Types Mandatory pattern Mandatory pattern Mandatory pattern
Supported Breaths
Control - - -
Target - - -
Feedback - - -
Expiratory Cycling - - -
Spontaneous Breaths
During mandatory inspiration
Not accommodated Accommodated Accommodated
Otherwise - - -
Synonyms
IPPVASSIST (Draeger)Synchronized cCntrolled Mandatory Ventilation (Hamilton)Volume Control (Maquet)VCV-A/C (Puritan-Bennett, Respironics)Volume A/C (Viasys)
BIPAPASSIST (Draeger)P-CMV (Hamilton)Pressure Control (Maquet)PCV-A/C (Puritan-Bennett, Respironics)Pressure A/C (Viasys)
Adaptive Pressure Ventilation CMVPRVC (Maquet)VC+A/C (Puritan-Bennet)PRVC A/C (Viasys)IPPV Assist Autoflow (Draeger)
Hybrid Mode: Synchronized Intermittent Mandatory Ventilation
Mandatory breaths
Inspiratory cycling Time or trigger Time or trigger Time or trigger
Control Volume Pressure (Pressure)
Target/Limit - - Volume-targeted
Feeadback - - Inter-breath
Expiratory cycling Time Time Time
Triggered Breaths
TypesMandatory and supported pattern
Mandatory and supported pattern
Mandatory and supported pattern
Supported Breaths
Control Pressure Pressure Pressure
Target - - -
Feedback - - -
Expiratory Cycling Flow Flow Flow
Spontaneous Breaths
During mandatory inspiration
Not accommodated Accommodated Accommodated
Otherwise Only if support is off Only if support is off Only if support is off
Synonyms
SIMV (Draeger, Hamilton)SIMV (VC)+PS (Maquet)VCV-SIMV (Puritan-Bennett, Respironics)Volume SIMV (Viasys)
P-SIMV (Hamilton)SIMV(PC)+PS (Maquet)PCV-SIMV (Puritan-Bennett, Respironics)Pressure SIMV (Viasys)
SIMV+AutoflowAdaptive Pressure Ventilation SIMV (Hamilton)SIMV (PRVC)+PS (Puritan-Bennett)PRVC SIMV (Viasys)
Hybrid Mode: Bi-Level Ventilatio
Mandatory breaths
Inspiratory cyclingTime or trigger
Time or trigger Time or trigger Time or trigger
Control Pressure Pressure Pressure Pressure
Target/Limit - - - -
Feeadback - - - -
Expiratory cyclingTime or trigger
Time or trigger Time or trigger Time or trigger
Triggered Breaths
InteractionMandatory and supported
Mandatory pattern and supported
Mandatory and supported
Mandatory and supported
Supported Breaths
Control Pressure Pressure Pressure Pressure
Target - - - -
Feedback - - - -
Expiratory Cycling Flow Flow Flow Flow
Spontaneous Breaths
During mandatory inspiration
Accommodated
Trigers suuport to PEEP+Psupport If this>Phigh (Hamilton DuoPAP)Plow+Psupport If this>Phigh (Hamilton APRV)PEEPL+PsuppIf this>PEEPH (Puritan-Bennett)
Triggers support to PRES HIGH + PSV if Thigh PSV is activated
Tigger support to PSV above PHigh
Otherwise Triggers support
Triggers support to PEEP+Psupport (Hamilton) DuoPAP)Plow+Psupport (Hamilton APRV)PEEPL+Psupp (Puritan-Bennett)
Triggers support to PREDSLOW=PSV
Triggers support to PSV above PEEP
SynonymsBIPAP (Draeger)
DuoPAP/APRV (Hamilton)BiLevel (Puritan-Bennet)
APRV/Bi-phasic (Viasys)
Bi-vent (Maquet)
THANK YOU
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