MODES OF MECHANICAL VENTILATION Mazen Kherallah, MD, FCCP POINTS OF DISCUSSIONS | | | | Advanced Basics: y Flow and Time y Limit and cycling y Rise Time y Volume vs Pressure Control Mandatory Modes of Ventilation y Controlled Mandatory Ventilation (CMV or IPPV) Triggered Modes of Ventilation y Continuous Positive Airway Pressure (CPAP) y Pressure Support Ventilation (PSV) Hybrid Modes of Ventilation y Assist Control Mode (A/C) y Synchronized Intermittent Mandatory Ventilation (SIMV) ADVANCED BASICS RESPIRATORY CYCLE Inspiration Expiration RELATIONSHIP BETWEEN TIDAL VOLUME, INSPIRATORY TIME AND FLOW Volume VT 3 Flow= 37.5 L/min VT 1 Flow= 30 L/min Insp Exp VT 2 Flow= 15 L/min Time Ti a RELATIONSHIP BETWEEN TIDAL VOLUME, INSPIRATORY TIME AND FLOW Volume Flow= 60 L/min Flow= 30 L/min VT 1 Flow= 20 L/min Insp Insp Insp Ti b Ti a Ti c ExpExp Time PRESSURE LIMITED BREATH Volume Pressure Limit Time EXPIRATORY FLOW CYCLING Flow 100% Flow Cycling 50% Time RISE TIME Pressure Flow Volume TI TE Time MANDATORY, SPONTANEOUS AND TRIGGERED INSPIRATORY CYCLING M M M M S S M Tsynch M M S M Tsupp Tsupp Tsupp Tsupp Tsupp M Tsupp VOLUME CONTROLLED INFLATION Pressure Flow Tidal Volume Volume TI TE Time VOLUME CONTROL BREATHS 50 Decreased Compliance Paw SEC cmH20 -20 120 1 2 3 4 5 6 INSP SEC Flow L/min 1 2 3 4 5 120 6 EXH If compliance decreases the pressure increases to maintain the same Vt VOLUME CONTROL WITH END-INSPIRATORY PAUSE End Inspiratory Pause Pressure Flow Tidal Volume Volume TI TE Time PRESSURE CONTROLLED INFLATION Rise Time Pressure Peak Inspiratory Flow Flow Tidal Volume Volume TI TE Time Volume/Flow Control Inspiration Pressure Control Expiration 20 Inspiration Expiration 20 Paw Pressure Paw 0 1 0 2 20 0 1 2 0 1 2 20 Volume 0 0 1 0 2 3 Flow 0 -3 3 Time (s) 0 -3 Time (s) TRIGGERED MODES OF VENTILATION CPAP and PSVV SPONTANEOUS BREATHING Pressure (cm H2O) Flow (L/m) Volume (mL) Time (sec) CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP) Pressure (cm H2O) CPAP Level Flow (L/m) Volume (mL) Time (sec) PRESSURE SUPPORT VENTILATION (PSV) Longer Inspiration Set PS Level Pressure (cm H2O) Better Efforts Flow Cycling Flow (L/m) Volume (mL) Time (sec) Patient Triggered, Flow Cycled, Pressure limited Mode CPAP+PSV Pressure (cm H2O) Set PS Level CPAP Level Flow Cycling Flow (L/m) Volume (mL) Time (sec) Patient Triggered, Flow Cycled, Pressure limited Mode TRIGGERED MODES OF VENTILATION PRESSURE SUPPORT VENTILATION Control Trigger Pressure Patient Limit Target Pressure Patient Triggered Flow Cycled Ventilation Cycle Flow PRESSURE OR VOLUME-TARGETED VENTILATION Advantages | 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 Disadvantages | | | 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 MANDATORY MODES OF VENTILATION CMV or IPPV MANDATORY MODES OF VENTILATION CMV Control Trigger Pressure Or Volume Limit Target Time Time Triggered Time Cycled Ventilation Cycle Time CONTROL MODE (PRESSURE-TARGETED VENTILATION) Set PC Level Time Cycling Pressure (cm H2O) Flow (L/m) Volume (mL) Time (sec) Time Triggered, Pressure Limited, Time Cycled Ventilation CONTROL MODE (VOLUME-TARGETED VENTILATION) Time Cycling Pressure (cm H2O) Dependent on CL & Raw Flow (L/m) Preset VT Volume Cycling Volume (mL) Time (sec) Time Triggered, Flow Limited, Volume Cycled Ventilation PRESSURE OR VOLUME-TARGETED VENTILATION Advantages | | Decreases the work of breathing (WOB) Helps maintain a normal PaCO2 Disadvantages | Not able to assist the ventilator HYBRID MODES OF VENTILATION SIMV and A/C HYBRID MODES OF VENTILATION A/C Control Trigger Pressure Or Volume Limit Target Time Or Patient Time or PatientTriggered Time Cycled Ventilation Cycle Time ASSISTED MODE (VOLUME-TARGETED VENTILATION) Time Cycling Pressure (cm H2O) Preset peak Flow Flow (L/m) Volume (mL) Time (sec) Patient Triggered, Flow limited, Volume Cycled Ventilation ASSISTED MODE (PRESSURE-TARGETED VENTILATION) Set PC Level Time Cycling Pressure (cm H2O) Flow (L/m) Volume (mL) Time (sec) Patient Triggered, Pressure Limited, Time Cycled Ventilation PRESSURE OR VOLUME-TARGETED VENTILATION Advantages | | | Decreases the work of breathing (WOB) Allows patients to regulate respiratory rate Helps maintain a normal PaCO2 Disadvantages | Alveolar hyperventilation HYBRID MODES OF VENTILATION SIMV/PS Breath Type Control Trigger Mandatory Pressure Or Volume Time Or Patient Spontaneous Pressure Patient Limit Cycle Time Pressure Flow SIMV (VOLUME TARGETED VENTILATION) Pressure (cm H2O) M M M Spontaneous Breaths Flow (L/m) Volume (mL) Time (sec) SIMV+PS (VOLUME TARGETED VENTILATION) Set PS Level Pressure (cm H2O) Tsynch Tsupp M Flow-cycled Flow (L/m) Volume (mL) Time (sec) SIMV + PS (PRESSURE-TARGETED VENTILATION) Tsynch Pressure (cm H2O) Tsynch Tsupp Set PC Level Time Cycled Set PS Level Flow-cycled Flow (L/m) Volume (mL) Time (sec) M M Tsupp M Cycles Flow (L/m) Pressure (cm H2O) HYBRID MODE VENTILATION: SUPPRESSION M M Time (sec) Tsupp Tsupp Tsupp HYBRID MODE VENTILATION: SYNCHRONIZATION (SIMV+PSV) M Tsupp Tsynch Pressure (cm H2O) Flow (L/m) Cycles Mandatory Cycle Time Time (sec) Triggered window for Triggered window for supported breaths synchronized breaths M Tsynch Tsupp SIMV Advantages | | | Maintains respiratory muscle strength by avoiding muscle atrophy Decreases mean airway pressure Facilitates ventilator discontinuation – “weaning”! Disadvantages | | When used for weaning, may be done too quickly and cause muscle fatigue Mechanical rate and spontaneous rate may asynchronous causing “stacking” y 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-limited Volume-targeted Feeadback - - Intra-breath Inter-breath Expiratory cycling Time Time Time Time None None None None Control - - - - Target - - - - Feedback - - - - Expiratory Cycling - - - - During mandatory inspiration Not accommodated Not accommodated Not accommodated Accommodated Otherwise Not accommodated Accommodated Not accommodated Accommodated Synonyms IPPV (Draeger) Controlled Mandatory Ventilation Intermittent Mandatory Ventilation IPPV (Draeger): trigger off, autoflow off IPPV (Draeger): trigger off, autoflow on Triggered Breaths Types Supported Breaths Spontaneous Breaths Triggered Modes of Ventilations Mandatory breaths Inspiratory cycling - - - Control - - - Target/Limit - - - Feeadback - - - Expiratory cycling - - - 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 During mandatory inspiration - - - Otherwise - - - Synonyms Assisted Spontaneus Breathing (Draeger) Spontaneous Mode (Hamilton, Puritan Bennet) Pressure Support (Maquet Pressure Support Ventilation (Viasys) CPAP (Respironics) Volume Support (Maquet, PuritanBennett) Propotional Assist Ventilation, Proportional Pressure Suport (Draeger) Propotional Assist Ventilation Plus (Puritan-Bennet) Triggered Breaths Types Supported Breaths Spontaneous Breaths 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 - - - 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 (PuritanBennett, Respironics) Pressure A/C (Viasys) Adaptive Pressure Ventilation CMV PRVC (Maquet) VC+A/C (PuritanBennet) PRVC A/C (Viasys) IPPV Assist Autoflow (Draeger) Spontaneous Breaths 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 Types Mandatory and supported pattern Mandatory and supported pattern Mandatory and supported pattern Supported Breaths Control Pressure Pressure Pressure Target - - - Feedback - - - Expiratory Cycling Flow Flow Flow During mandatory inspiration Not accommodated Accommodated Accommodated Otherwise Only if support is off Only if support is off Only if support is off SIMV (Draeger, Hamilton) SIMV (VC)+PS (Maquet) VCV-SIMV (PuritanBennett, Respironics) Volume SIMV (Viasys) P-SIMV (Hamilton) SIMV(PC)+PS (Maquet) PCV-SIMV (PuritanBennett, Respironics) Pressure SIMV (Viasys) SIMV+Autoflow Adaptive Pressure Ventilation SIMV (Hamilton) SIMV (PRVC)+PS (Puritan-Bennett) PRVC SIMV (Viasys) Spontaneous Breaths Synonyms Hybrid Mode: Bi-Level Ventilatio Mandatory breaths Inspiratory cycling Time or trigger Time or trigger Time or trigger Time or trigger Control Pressure Pressure Pressure Pressure Target/Limit - - - - Feeadback - - - - Expiratory cycling Time or trigger Time or trigger Time or trigger Time or trigger Mandatory and supported Mandatory pattern and supported Mandatory and supported Mandatory and supported Control Pressure Pressure Pressure Pressure Target - - - - Feedback - - - - Expiratory Cycling Flow Flow Flow Flow 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 Synonyms BIPAP (Draeger) DuoPAP/APRV (Hamilton) BiLevel (Puritan-Bennet) APRV/Bi-phasic (Viasys) Bi-vent (Maquet) Triggered Breaths Interaction Supported Breaths Spontaneous Breaths During mandatory inspiration THANK YOU
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