Conflict of Interest Disclosure Robert M Kacmarek Unconventional Techniques Using Your ICU Ventilator!" 5-5-17 FOCUS Bob Kacmarek PhD, RRT Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts I disclose the following financial relationships with commercial entities that produce healthcare-related related products or services relevant to the content I am presenting: Company Relationship Content Area Covidien Consultant Artifiical Airways Covidien Grant Mech Vent Orange Med Consultant Mech Vent Teleflex Consultant Humidification PRVC and VS Pressure regulated volume control and Volume support Both target a preset V T and adjust the level of pressure ventilation needed to ensure the delivery of the V T PRVC - set rate, inspiratory time, minute ventilation/v T and pressure limit VS - set minute ventilation/v T and pressure limit PRVC Initial test breath ( 5 or 10 cmh 2 O ) Calculate pressure needed to delivery V T Test breathes provided at some percentage of the target V T Then to pressure level needed to insure actual V T delivery Subsequent pressure changes up to 3 cmh 2 O per breath Jabar ICM 2005;31:1181 Evaluate the response of volume support ventilation vs. pressure support ventilation with the addition of increased dead space HME in 10 patients weaning! VS increased indexes of ventilatory work and effort 2.4 to 4 times greater than with PS, inducing respiratory distress in two patients! The pressure during VS decreased from 15.0+6.5 to 9.1+4.8 cm H 2 O! Jabar ICM 2005;31:1181 1
Proportional Assist Ventilation (PAV) Neurally Adjusted tdventialtory tilt Assist it (NAVA) Younes ARRD 1992;145:114 Proportional Assist Ventilation PAV based on the equation of motion Increases or decreases ventilatory support in proportion to patient effort Similar in concept to power steering Tracks changes in patient effort and adjusts ventilator output to reduce work Introduced by Younes in 1992 Younes M, ARRD 1992;145:121 Equation of Motion for the respiratory system Ventilator output :Triggering, Cycling Control of flow, rise time and pressure Paw + Pmus = V x R + V V x E Patient response Mechanical Chemical Reflex Behavioral PAV Younes M. AARD 1992;145:121 Xirouchaki ICM 2008;34:2026 The use of PAV vs. PSV in critically ill patients for 48 hours On controlled ventilation > 36 hours Ability to trigger vent > 10/min PaO 2 > 60 with F I O 2 < 0.65 and total PEEP < 15 cmh 2 O ph > 7.30 No severe hemodynamic instability No severe bronchospasm A stable neurological status 2
Xirouchaki ICM 2008;34:2026 Failure rate 11% vs. 22%, p = 0.04 Proportion of patients exhibiting pt-vent dys-synchrony synchrony 5.6% vs. 29%, p < 0.001 001 The proportion of patients meeting criteria for unassisted breathing did not differ Xirouchaki ICM 2008;34:2026 Bosma CCM 2007;35:1048 PSV vs. PAV during sleep cross over study one night each mode randomly applied Both set to decrease inspiratory WOB by 50% Arousals/hr 16 (2-74) vs. 9 (1-41) p < 0.02 Overall sleep quality better PAV p<005 0.05 MV and V T lower and CO 2 greater PAV Awakenings/hr 5.5 (1-24) vs. 3.5 (0-24) Rapid eye movement 4% 90-23) vs. 9% (90-31) Slow wave sleep 1% (0-10) vs. 3% (0-16) Asynchronies/hr 53+5959 vs. 24+15 p < 0.02 Proportional Assist Ventilation Requires patients have an intact ventilatory drive! Requires ongoing assessment of lung mechanics! Unable to deal with auto-peep!! Neurally Adjusted Ventilatory Assist - NAVA Neurally Adjusted Ventilatory Assist - NAVA Sinderby Nature Med 1999;5:1433 Sinderby Nature Med 1999;5:1433 3
Sinderby Nature Med 1999;5:1433 Sinderby Nature Med 1999;5:1433 Delisle Ann Inten Care 2011;1:42 Piquilloud ICM 2012;38: 1624 De la Oliva Submitted for Publication 12 pediatric patients 5 months to 12 years PS, PS optimized vs. NAVA 30 min trials each application Compared asynchronies, and Variability in ventilatory pattern Pedro de la Oliva Submitted for Publication 4
PAV NAVA PAV vs. NAVA Uses airway pressure and flow measurements No specific equipment needed Available invasively/noninvasively (different ventilators) Use with patients greater than 20 kg Affected by leaks (current invasive) and autopeep Uses measurement of diaphragm EMG (EAdi) activity Requires use of a special catheter Available invasively/noninvasively Useful in neonates, children and adults Unaffected by leaks and autopeep Major Question Regarding PAV and NAVA! Who Knows Better How to Ventilate the Clinician or the Patient? Pressure Airway Pressure Release Ventilation - APRV Time APRV Lung recruitment Improved oxygenation Spontaneous breathing Minimal sedation Improved Hemodynamic status Lung protection APRV PEEP: Established by limiting exhalation autopeep! Ventilation: Change high to low CPAP and spontaneous breathing at high CPAP! Increased effort to breathe! Markedly reduced intra-thoracic pressure! Induced lung Injury! Fast time constant lung unit opening and closing with each change from high to low CPAP Kacmarek et al Chest 1995;108:1073 5
Ventilation Change low to high CPAP frequently very large V T Spontaneous breathing at high CPAP low V T but! Increased effort to breathe! Neuman ICM 2002;28:1742 Improved Hemodynamics Increased ventilatory efforts! Markedly reduced intrathoracic 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 (V T ) to functional residual capacity ratio FRC is the resting FRC, any volume added by the addition of PEEP is added to the volume change Stress = k x Strain, where k equals the specific lung elastance (13.5 cmh 2 O/ml). If the Strain is 2 the Stress is 27 cmh 2 O - the TPP in which the FRC doubles. Neuman ICM 2002;28:1742 6
Airway Pressure Release Ventilation: End Inspiratory Transpulmonary Pressure TPP = Pplat - Ppl 35 cmh 2 O = 22 cmh 2 O (-13 cmh 2 O) Airway Pressure Release Ventilation: End Inspiratory Transpulmonary Pressure TPP = Pplat - Ppl 43 cmh 2 O = 30 cmh 2 O (-13 cmh 2 O) Maxwell J Trauma 2010;69:501 J Trauma 2010;69:501 Maxwell J Trauma 2010;69:501 Maxwell J Trauma 2010;69:501 7
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 the ARDSnet or stated before the ARDSnet Compared 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;56:190 Daoud et al Respir Care 2012;57:1325 McMullen et al PLoS One 2012;7:e40190 No Data to support that APRV 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! Kallet Respir Care 2011;56:190 Daoud et al Respir Care 2012;57:1325 McMullen et al PLoS One 2012;7:e40190 No Data to support that APRV 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! Summary Ventilate all patients with a Lung protective approach FROM the moment ventilation starts Use recruitment maneuvers and decremental PEEP trial to set PEEP Esophageal pressure measurement necessary for the determination of the limit of peak inspiratory plateau pressure but not for the setting of PEEP I do not recommend APRV as an approach to manage hypoxemic respiratory failure Thank You 8