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Sophisticated Ventilator Modes Sophisticated Ventilator Modes ––When and How to UseWhen and How to Use

Bob Kacmarek PhD, RRTBob Kacmarek PhD, RRT

Harvard Medical School Harvard Medical School

Massachusetts General HospitalMassachusetts General Hospital

Boston, MassachusettsBoston, Massachusetts1010--2727--16 FOCUS16 FOCUS

Conflict of Interest DisclosureRobert M Kacmarek

I disclose the following financial relationships with commercial entities that produce healthcare-related products or services relevant to the content I am presenting:

Company Relationship Content AreaMedtronic Consultant Artificial AirwaysMedtronic Grant Mech VentVenner Medical Grant Artificial AirwaysOrange Medical Consultant Mech VentTeleflex Consultant Humidification

PRVC and VSPRVC and VS

Pressure regulated volume control and Pressure regulated volume control and Volume supportVolume support

Both target a preset VBoth target a preset VTT and adjust the level and adjust the level of pressure ventilation needed to ensure theof pressure ventilation needed to ensure theof pressure ventilation needed to ensure the of pressure ventilation needed to ensure the delivery of the Vdelivery of the VTT

PRVC PRVC -- set rate, inspiratory time, minute set rate, inspiratory time, minute ventilation/Vventilation/VTT and pressure limitand pressure limit

VS VS -- set minute ventilation/Vset minute ventilation/VTT and pressure and pressure limitlimit

PRVCPRVC

Initial test breath ( 5 or 10 cmHInitial test breath ( 5 or 10 cmH22O )O )Calculate pressure needed to delivery VCalculate pressure needed to delivery VTT

Test breathes provided at some percentage of Test breathes provided at some percentage of the target Vthe target VTTthe target Vthe target VTT

Then to pressure level needed to insure actual Then to pressure level needed to insure actual VVTT deliverydeliverySubsequent pressure changes up to 3 cmHSubsequent pressure changes up to 3 cmH22O O per breathper breath

Jabar ICM 2005;31:1181Jabar ICM 2005;31:1181

Evaluate the response of volume support Evaluate the response of volume support ventilation vs. pressure support ventilation ventilation vs. pressure support ventilation with the addition of increased dead space with the addition of increased dead space ––HME in 10 patients weaning!HME in 10 patients weaning!HME in 10 patients weaning!HME in 10 patients weaning!VS increased indexes of ventilatory work and VS increased indexes of ventilatory work and effort 2.4 to 4 times greater than with PS, effort 2.4 to 4 times greater than with PS, inducing respiratory distress in two patients!inducing respiratory distress in two patients!The pressure during VS decreased from The pressure during VS decreased from 15.0+6.5 to 9.1+4.8 cm H15.0+6.5 to 9.1+4.8 cm H22O!O!

Jabar ICM 2005;31:1181Jabar ICM 2005;31:1181

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Proportional Assist Ventilation(PAV)

N ll Adj t d V ti lt A i tNeurally Adjusted Ventialtory Assist(NAVA)

Younes ARRD 1992;145:114

Proportional Assist VentilationProportional Assist Ventilation

PAV based on the equation of motionPAV based on the equation of motion

Increases or decreases ventilatory support in Increases or decreases ventilatory support in proportion to patient effort proportion to patient effort

Similar in concept to power steeringSimilar in concept to power steering

Tracks changes in patient effort and adjusts Tracks changes in patient effort and adjusts ventilator output to reduce workventilator output to reduce work

Introduced by Younes in 1992Introduced by Younes in 1992Younes M, ARRD 1992;145:121Younes M, ARRD 1992;145:121

Equation of Motion Equation of Motion for the respiratory systemfor the respiratory system

Paw + Pmus = V’ x R + Paw + Pmus = V’ x R + V x EV x E

Ventilator output :Triggering, Cycling

Control of flow, rise time and pressure

MechanicalPatient response Chemical

ReflexBehavioral

PAVPAV

Younes M. AARD 1992;145:121

Xirouchaki ICM 2008;34:2026Xirouchaki ICM 2008;34:2026

The use of PAV vs. PSV in critically ill patients The use of PAV vs. PSV in critically ill patients for 48 hoursfor 48 hoursOn controlled ventilation > 36 hoursOn controlled ventilation > 36 hoursAbility to trigger vent > 10/minAbility to trigger vent > 10/minAbility to trigger vent > 10/minAbility to trigger vent > 10/minPaOPaO22 > 60 with F> 60 with FIIOO22 < 0.65 and total PEEP < 15 < 0.65 and total PEEP < 15 cmHcmH22OOpH > 7.30pH > 7.30No severe hemodynamic instabilityNo severe hemodynamic instabilityNo severe bronchospasmNo severe bronchospasmA stable neurological statusA stable neurological status

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Xirouchaki ICM 2008;34:2026Xirouchaki ICM 2008;34:2026

Failure rate 11% vs. 22%, p = 0.04Failure rate 11% vs. 22%, p = 0.04

Proportion of patients exhibiting ptProportion of patients exhibiting pt--vent vent dysdys synchrony 5 6% vs 29% p < 0 001synchrony 5 6% vs 29% p < 0 001dysdys--synchrony 5.6% vs. 29%, p < 0.001synchrony 5.6% vs. 29%, p < 0.001

The proportion of patients meeting The proportion of patients meeting criteria for unassisted breathing did not criteria for unassisted breathing did not differdiffer

Xirouchaki ICM 2008;34:2026Xirouchaki ICM 2008;34:2026

Bosma CCM 2007;35:1048Bosma CCM 2007;35:1048PSV vs. PAV during sleep cross over study one PSV vs. PAV during sleep cross over study one night each mode randomly appliednight each mode randomly applied

Both set to decrease inspiratory WOB by 50%Both set to decrease inspiratory WOB by 50%

Arousals/hr 16 (2Arousals/hr 16 (2--74) vs. 9 (174) vs. 9 (1--41) p < 0.0241) p < 0.02

Overall sleep quality better PAV p < 0 05Overall sleep quality better PAV p < 0 05Overall sleep quality better PAV p < 0.05Overall sleep quality better PAV p < 0.05

MV and VMV and VTT lower and COlower and CO22 greater PAVgreater PAVAwakenings/hr 5.5 (1Awakenings/hr 5.5 (1--24) vs. 3.5 (024) vs. 3.5 (0--24)24)

Rapid eye movement 4% 90Rapid eye movement 4% 90--23) vs. 9% (9023) vs. 9% (90--31)31)

Slow wave sleep 1% (0Slow wave sleep 1% (0--10) vs. 3% (010) vs. 3% (0--16)16)

Asynchronies/hr 53Asynchronies/hr 53++59 vs. 2459 vs. 24++15 p < 0.0215 p < 0.02

Proportional Assist VentilationProportional Assist Ventilation

Requires patients have an intact Requires patients have an intact ventilatory drive!ventilatory drive!

Requires ongoing assessment of lungRequires ongoing assessment of lungRequires ongoing assessment of lung Requires ongoing assessment of lung mechanics!mechanics!

Unable to deal with autoUnable to deal with auto--PEEP!!PEEP!!

Neurally Adjusted Ventilatory Assist Neurally Adjusted Ventilatory Assist --NAVANAVA

Sinderby Nature Med 1999;5:1433Sinderby Nature Med 1999;5:1433

Neurally Adjusted Ventilatory Assist Neurally Adjusted Ventilatory Assist --NAVANAVA

Sinderby Nature Med 1999;5:1433Sinderby Nature Med 1999;5:1433

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Sinderby Nature Med 1999;5:1433Sinderby Nature Med 1999;5:1433 Sinderby Nature Med 1999;5:1433Sinderby Nature Med 1999;5:1433

Delisle Ann Inten Care 2011;1:42

Piquilloud ICM

2012;38: 1624

De la Oliva Submitted for PublicationDe la Oliva Submitted for Publication

12 pediatric patients 5 months to 12 pediatric patients 5 months to 12 years 12 years

PS PS optimized vs NAVAPS PS optimized vs NAVAPS, PS optimized vs. NAVAPS, PS optimized vs. NAVA

30 min trials each application30 min trials each application

Compared asynchronies, and Compared asynchronies, and Variability in ventilatory patternVariability in ventilatory pattern

Pedro de la Oliva Submitted for PublicationPedro de la Oliva Submitted for Publication

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Schmidt Critical Care 2015;19:56Schmidt Critical Care 2015;19:56

Compared PSV, PAV and NAVA at 100%: VCompared PSV, PAV and NAVA at 100%: VTT 6 to 6 to 8 ml/kg, at 50% and 150% in 16 pts8 ml/kg, at 50% and 150% in 16 pts

PAV and NAVA prevent increased VPAV and NAVA prevent increased VTT 150%150%

Coefficient of Variation of respiratory pattern higher Coefficient of Variation of respiratory pattern higher PAV and NAVA than PSVPAV and NAVA than PSV

Ineffective triggering lower PAV and NAVA, Ineffective triggering lower PAV and NAVA, double triggering lower PAV and PSVdouble triggering lower PAV and PSV

PAV and NAVA prevented overPAV and NAVA prevented over--distention, distention, improved improved neuroneuro--mechanical coupling, restored mechanical coupling, restored variability, and improved synchronyvariability, and improved synchrony

PAV vs. NAVAPAV vs. NAVAPAVPAV

Uses airway pressure and flow measurementsUses airway pressure and flow measurements

No specific equipment neededNo specific equipment needed

Available invasively/noninvasively (different ventilators)Available invasively/noninvasively (different ventilators)

Use with patients greater than 20 kgUse with patients greater than 20 kg

Affected by leaks (current invasive) and autoPEEPAffected by leaks (current invasive) and autoPEEP

NAVANAVAUses measurement of diaphragm EMG (EAdi) activityUses measurement of diaphragm EMG (EAdi) activity

Requires use of a special catheterRequires use of a special catheter

Available invasively/noninvasively Available invasively/noninvasively

Useful in neonates, children and adultsUseful in neonates, children and adults

Unaffected by leaks and autoPEEPUnaffected by leaks and autoPEEP

Major Question Regarding PAV and NAVA!

Who Knows Better How to Ventilate – the Clinician or the Patient?

Airway Pressure Release Ventilation - APRV

Pre

ssur

e

Time

APRV

Lung recruitment – Improved oxygenationSpontaneous breathing –Spontaneous breathing Minimal sedation Improved Hemodynamic statusLung protection

APRV

PEEP: Established by limiting exhalation –autoPEEP!Ventilation: Change high to low CPAP and spontaneous breathing at high CPAP!spontaneous breathing at high CPAP! Increased effort to breathe!Markedly reduced intra-thoracic pressure!Induced lung Injury!

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Fast time constant lung unit opening and closing with each change from high to low CPAP

Kacmarek et al Chest 1995;108:1073

Ventilation

Change low to high CPAP frequently very large VT

Spontaneous breathing at highSpontaneous breathing at high CPAP low VT but! Increased effort to breathe!

Neuman ICM 2002;28:1742

Improved Hemodynamics

Increased ventilatory efforts!Markedly reduced intra-thoracic pressure!Increased Cardiac output!

Induced Lung Injury

Plateau Pressure and Tidal Volume: Small tidal volumes and low plateau pressures are used to avoid over distension

Over distension is best evaluated by Transpulmonary pressure

TPP = Pplat – Ppl

Chiumello AJRCCM 2008;178:346“Stress” is defined as the internal distribution of the counterforce per unit area that balances and reacts to an external load.

Lung Stress = Transpulmonary pressure“Strain” is the associated deformation of the structure.

Lung Strain = volume change (VT) to functional residual capacity ratioFRC is the resting FRC, any volume added by the addition of PEEP is added to the volume changeStress = k x Strain, where k equals the specific lung elastance (13.5 cmH2O/ml). If the Strain is 2 the Stress is 27 cmH2O - the TPP in which the FRC doubles.

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Neuman ICM 2002;28:1742

Airway Pressure Release Ventilation: End Inspiratory

Transpulmonary Pressure

TPP = Pplat - PplTPP Pplat Ppl

35 cmH2O = 22 cmH2O – (-13 cmH2O)

Airway Pressure Release Ventilation: End Inspiratory

Transpulmonary Pressure

TPP = Pplat - PplTPP Pplat Ppl

43 cmH2O = 30 cmH2O – (-13 cmH2O) J Trauma 2010;69:501

Maxwell J Trauma 2010;69:501Maxwell J Trauma 2010;69:501

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Maxwell J Trauma 2010;69:501

J Trauma Acute Care Surg 2012;73:507-510

Andrews J Trauma Acute Care Surg 2013;75:635

Compared retrospective data from Shock Trauma to that of 16 other non-RCTs; 8 of which were retrospective reviews and in 7 the time period was entirely before p ythe ARDSnet or stated before the ARDSnetCompared 231 pts to 63,646 patients but did not match patients Incidence of ARDS 14.0% vs. 1.3% Hospital Mortality 14.1% vs. 3.9%

Kallet Respir Care 2011;56:190Daoud et al Respir Care 2012;57:1325

McMullen et al PLoS One 2012;7:e40190

No Data to support that APRV improves survival!improves survival!

No data to support that APRV decreases the length of ICU stay!

No data to support that APRV decreases the length of mechanical ventilation!

APRV – Caution!NO data to indicate APRV is beneficial for management or rescue in ARDS or trauma or any clinical application!

Does not prevent ARDS!

Potentially establishes transpulmonary pressure inducing lung injury!

No demonstrated mortality benefit regardless of setting!

No demonstrated LOMV or ICU LOS or Hospital LOS benefit regardless of setting!

Thank YouThank You