Basic ventilatory modes

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)


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


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


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


Decreases the work of breathing (WOB)

Helps maintain a normal PaCO2

Not able to assist the ventilator


HYBRID MODES OF VENTILATIONSIMV and A/C

HYBRID MODES OF VENTILATIONA/C


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


Decreases the work of breathing (WOB)

Allows patients to regulate respiratory rate

Helps maintain a normal PaCO2

Alveolar hyperventilation


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


M Tsupp MM Tsupp

M M

Tsupp Tsupp

HYBRID MODE VENTILATION: SYNCHRONIZATION(SIMV+PSV)

HYBRID MODE VENTILATION: SYNCHRONIZATION(SIMV+PSV)


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


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


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


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


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

Basic ventilatory modes

Health & Medicine

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