1 Advanced Ventilator Management Transpulmonary Guided Ventilation Esophageal BalloonaryThom Petty BS RRT Lead Clinical Specialist – EastCareFusion Critical Care Ventilation
2 ObjectivesIdentify the limitations that current Respiratory Mechanics impose upon the management of mechanical ventilation.Review the hazards associated with positive pressure ventilation and the sequelae of Ventilator-Induced Lung Injury.Discuss the role of chest wall, pleura and abdominal pressures during positive pressure ventilationIntroduce the measurement of Transpulmonary Pressure as a valuable ventilation management tool.Review a Case Study regarding the use of transpulmonary pressures in the management of ventilator settings.
4 Mechanics 101: Motion of Air Equation PAO = ( VL / CRS) ( F x RAW )PAO = Pressure at the Airway OpeningVL = Volume in the LungCRS = Compliance of the Respiratory System(Lung + Pleura)F = Flow Rate of Gas in L/sRAW = Resistance of the Airway and ETT( pressure / flow)
5 As the Lung Inflates Pressure in the Airway (Paw) Measured at the circuit wyeNot the actual pressure in the lungs but the pressure of the entire respiratory systemReflects both lung and pleural pressuresPeri-pulmonary/Pleural Pressure (Pes)Pressure that is imposed upon the lungs by the Chest Wall and AbdomenCan be approximated by measuring pressures within the EsophagusPressure within the Alveoli (Ptp)The TRUE pressure within the lungPtp = Paw – PesPawPesPtp
6 Our Current Respiratory Mechanics Toolbox Inspiratory HoldMeasures the Plateau Pressure of the entire Respiratory SystemIndicator of end-inspiratory lung distensionStatic ComplianceReflects the compliance of the entire Respiratory SystemExpiratory HoldMeasures the amount of intrinsic PEEP of the entire Respiratory System
8 The Hazard that is Mechanical Ventilation mechanical ventilation can no longer be seen merely as a supportive therapy in ali and ards,but as a treatment modality capable of significantly influencing the course of pulmonary disease and clinical outcome.Viana M, Jornal de Pediatria, 2004
9 Just What is Positive-Pressure Ventilation? Just what is it that is delivered by the ventilator to the patients’ lungs?VolumeFlowPressure
10 The Alveoli – Not Grapes on a Straw It’s important to remember that alveoli are not the “cluster of grapes at the end of a straw” like we envisioned in school. They are more like a sponge sharing common walls and full of holes.
11 The Alveolar Structure Adjacent alveoli and terminal bronchioles share common wallsForces acting on one lung unit are transmitted to those around it (interdependence)Under conditions of uniform expansion, all lung units will be subject to a similar transpulmonary pressure.However, if the lung is unevenly expanded, such forces may vary considerably.
12 Dynamic Alveolar Mechanics in the Uninjured Lung Healthy alveoli:Undergo relatively small changes in size during ventilation unless they totally collapse or re-expand.Ventilation may occur primarily with changes in the size of the alveolar duct or conformational changes as a result of alveolar foldingAlveoli in ALI:Undergo large changes in alveolar sizeWidespread alveolar recruitment/derecruitment predominate.Can cause significant shear stress-induced lung injuryGross tearing of the alveolar wallInjury to the cell membraneUltrastructural injuryWilson, J Appl Physiol, 2001Carney, CCM, 2005Steinberg, AJRCCM, 2004
13 Alveolar Interdependence When an alveolus collapses, the traction forces that are exerted on its walls by adjacent expanded lung units increase as they are applied to a smaller surface area.These forces will promote re-expansion at the expense of greatly increased and potentially harmful stress at the interface between collapsed and expanded lung unitsAt a transpulmonary pressure of 30 cmH2O it has been calculated that re-expansion pressures could reach 140 cmH2O.
14 The Problems with Positive-Pressure Ventilation Positive-pressure ventilation departs radically from the physiology of breathing spontaneously.During inhalation positive intrathoracic pressures are created.These inspiratory-phase pressures are not homogenously distributed throughout the lung:Effectively distributed through compliant lungFlow is attenuated in low-compliant areasThis heterogenocity can result in overdistension of compliant “healthy” lung and underdistension of non-compliant “injured” lung
15 The Problems with Positive-Pressure Ventilation Early on in the history of positive-pressure ventilation it was recognized that lungs that were ventilated to high pressures have a propensity to develop air leaks.Thus began the early focus on barotraumaHowever, further research has revealed that alveoli that do not overdistend were unlikely to experience injury.Excessive lung volume (volutrauma) rather than excessive airway pressures produced lung injury.At the other end of the spectrum, ventilation using low end expiratory volumes that allowed repetitive alveolar opening and collapse (atelectrauma) was also identified as injurious.Whitehead, Thorax, 2002Diaz, Crit Care Med 2010
16 The Problems with Positive-Pressure Ventilation The immediate macroscopic physiological side-effects of positive-pressure ventilation are readily recognized and easily understood.However, there are significant microscopic physiological interactions which are less obvious, more insidious, and may only produce complications if ventilation is prolonged.Increased permeability of the alveolar/capillary membraneIncreased production of pro-inflammatory mediators within the lungLung-protective ventilation strategies are directed primarily towards volume and pressure limitation during the inspiratory phase and maintenance of alveolar recruitment during the expiratory phase.
17 Ventilator-Induced Lung Injury Volutrauma Classic study applied excessive alveolar pressures to both volume-limited lungs (chests bound to prevent alveolar expansion) and volume-unlimited lungs (chests unbound with unchecked alveolar expansion)Less lung damage in the volume-limited lungs (alveoli with limited expansion) than in the volume-unlimited lungs (alveoli in the unbound chest).
18 Ventilator-Induced Lung Injury Volutrauma & Inflammation Study investigating the release of “Lung Flooding” factors in Rodents ventilated with three modes:HiP/HiVHigh Pressure (45 cmH2O)High VolumeLoP/HiVLow Pressure (neg.pres.vent)HiP/LoVLow Volume (chest bound)Dreyfuss,D ARRD 1988;137:1159
19 Ventilator-Induced Lung Injury Take-Home Points - Volutrauma Mechanical and Biochemical in natureCaused by excessive End-Inspiratory VolumesIndicated by elevated end-inspiratory (Plateau) pressuresMay result from a combination of “Safe” Vt + PEEPEven “safe” Vt’s may severely over-inflate normal alveoli due to heterogenicity of airflow within the lungQUESTION: How can a clinician determine if alveoli are over-distended at end-inspiration?
20 Ventilator-Induced Lung Injury Atelectrauma Research has revealed that repeated cyclical collapse & re-expansion of alveoli results in a release of cytokines and the reinforcement and amplification of the local and systemic inflammatory response.Interleukin-6Interleukin-11Interleukin-γTissue Necrosis Factor-α
21 Ventilator-Induced Lung Injury Take-home Points - Atelectrauma Associated with repeated opening and closing of alveoli during ventilatory phasingAssociated with regional differences in ventilationWorsens surfactant dysfunctionRelease of inflammatory mediators into alveolar spaces and into the systemic circulationQUESTION: How can the clinician determine what PEEP is necessary to keep the alveoli open at end-exhalation
22 Presumed Mechanism for VILI Mechanical Disruption of Pulmonary EpitheliumMechanotransductionCell & Tissue DisruptionUpregulation & release ofCytokines &, ChemokinesSubsequent leucocyte attraction and activationPulmonary Inflammation: VILISystemic Spillover:SIRS / MODSMECHANOTRANSDUCTION – Conversion of Mechanical Stimiuls into Chemical ReactionSIRS – systemic inflammatory Response SyndromeMODS – Multi Organ Dysfunction syndrome
24 Lung-Protective Ventilation Theory Gattinoni’s CT studies of ALI/ARDS lungs revealed that ALI/ARDS lung is not a stiff organ made up of homogeneously stiff lung units with low static compliance but is a multi-compartmental heterogeneous structure in which there is a portion of aerated normal tissue with normal compliance (baby lung).Limiting VILI should be accomplished through an Lung Protective approach to ventilator management which includes:Volume & pressure limitationModest PEEP & Plateau pressuresThe challenge is to maintain acceptable gas exchange while avoiding harmful mechanical ventilation practices. The need for potentially injurious pressures, volumes, and FiO2’s must be weighed against the benefits of gas exchange support.
25 Lung-Protective Ventilation Research 1988Amato et alBrazil29 pts: Vt < 6ml/kg, Pplat < 20cmH2O24 pts: Vt = 12ml/kg, PaCO mmHg38% Mortality71% Mortality1998Stewart et alCanada60 pts: Vt < 8ml/kg, Ppeak < 30cmH2O60 pts: Vt 10-15ml/kg, Ppeak < 50cmH2O50% Mortality at disch47% Mortality at dischBrochard et alMultinational58 pts: Vt 6-10ml/kg, Pplat < cmH2O58 pts: Vt 10-15ml/kg, PaCO mmHg47% Mortality at 60 days38% Mortality at 60 days1999Brower et alUSA26 pts: Vt 5-8ml/kg, Pplat <30 cmH2O26 pts: Vt 10-12ml/kg, Pplat < cmH2O46% Mortality at disch2000ARDSnetwork432 pts: Vt 6ml/kg, Pplat < 30 cmH2O429 pts: Vt 12ml/kg, Pplat < 50 cmH2O31% Mortality at disch/180 d40% Mortality at disch/180 d2006Villar et alSpain50 pts: Vt 5-8ml/kg, LIP + 2cmH2O53 pts: Vt 9-11ml/kg, PEEP >5 cmH2O32% Mortality in ICU53% Mortality in ICUThere have been six randomized controlled trials evaluating the effect of lung-protective ventilation in comparison with conventional approaches:
26 Lung-Protective Controversies The common denominator of the intervention sides of these trials is the use of lower Vt and limited Plateau Pressures.Many attempts have been made to understand the differences in the survival outcomes of these six RCT’s as well as to clarify whether a low Vt strategy benefits patients with ALI/ARDS.A 2002 meta-analysis by Eichacher of the trials revealed:The control arms of the “non-beneficial” RCT’s actually had lower Pplat’s (a surrogate for end-inspiratory alveolar pressure) than in the two beneficial armsCould the survival benefit of the two “non-beneficial” RCT’s be related to the larger-than-routine Vt’s in the control arms?Could the differences be related to Pplat rather than Vt?Eichacker PQ, Am J Resp Crit Care Med 2002
27 The Handful of Ventilator Settings FiO2Accurately measuredRespiratory RateAccurately measuredPEEPMeasured but not accurateTidal VolumeAccurately measuredPlateau PressureMeasured but not accurate
28 The Problem with Airway Pressures A key limitation to mechanical ventilators is that they report peak airway pressureswithout distinguishing compliance that reflects intrinsic lung mechanics or chest wall and abdominal pressuresPiraino T, Respiratory Care, April 2011
29 The Two Settings We Estimate PEEPMeasured but not accuratePlateau PressureMeasured but not accurate
30 The Two Settings we Estimate: PEEP Measured at the end of exhalation PEEP is the pressure that is exerted by the volume of gas that is remaining in the lungs (FRC)Although ventilation with Low Vt’s & Plateau Pressures is generally accepted by the critical-care community, the optimal level of PEEP at which to ventilate remains unclear.PEEP levels exceeding the “traditional” values of 5-12 cmH2O have been shown to minimize cyclical alveolar collapse and the corresponding shearing injury.However, potential adverse consequences including circulatory depression and lung overdistension may outweigh the benefitsUse of PEEP < 10cmH2O leads to an increase in mortalityAmato M., 8th World Congress, Sydney, AustraliaDreyfuss, Crit Care Med, 1998Gattinoni, NEJM, 2006Muscedere , Am J Respir Crit Care Med. 1994
31 The Two we Estimate: PEEP Research There have been three randomized controlled trials comparing higher versus lower levels of PEEP in ALI/ARDS:2010 – Briele Meta-AnalysisDifferences in hospital mortality not statically significantSignificant reduction of death in the ICU in the High PEEP group2004ARDSNetALVEOLIUSA276 pts: Mean PEEP = 14.7cmH2O273 pts: Mean PEEP = 8.9cmH2O25% Mortality at disch27.5% Mortality at disch2008MeadeLOVSMultinational508 pts: Mean PEEP = 15.6cmH2O475 pts: Mean PEEP = 10.1cmH2O36% Mortality at disch40% Mortality at dischMercatEXPRESSFrance382 pts: Mean PEEP = 14.6cmH2O385 pts: Mean PEEP = 7.1cmH2O35% Mortality at 60 days39% Mortality at 60 days
32 The Two we Estimate: The PEEP Controversy Low PEEP/High FiO2 ProtocolFiOPEEPHigh PEEP/Low FiO2 ProtocolFiOPEEP
33 The Two we Estimate: Optimal PEEP PEEP TableTable of FiO2 & PEEP combinations to achieve PaO2 or SpO2 in target rangeMaximal PEEP without overdistensionUse of highest PEEP while maintaining Pplat < 30 cmH2OGas ExchangeLowest shunt (highest PaO2), lowest deadspace (lowest PaCO2), best oxygen delivery (CaO2 x C.O.)ComplianceUse of the highest PEEP that results in the highest respiratory-system complianceStress IndexObserve the Pressure/Time Curve during constant flow inhalation for signs of tidal recruitment and overdistensionPressure/Volume CurveSet PEEP slightly higher than Lower Inflection PointImagingComputed tomography, Electrical impedence tomography, UltrasoundEsophageal Pressure MonitoringEstimate the intra-pleural pressure with the measurement of Esophageal Pressure then determine optimal PEEPIdeal PEEP is defined as:High enough to induce alveolar recruitment, keeping the lungmore aerated at end-exhalation, while not distending “good”alveoliLow enough to prevent hemodynamic impairment &overdistension
34 The Two we Estimate: Alveolar Recruitability Briele also suggests that the beneficial impact of reducing intra-tidal alveolar opening and closing by increasing PEEP prevailed over the effects of increasing alveolar distention in ALI/ARDS patients with higher lung recruitabilityIn ALI/ARDS patients with low potential for recruitment, the resulting over-distension associated with PEEP increases was harmfulHow To Determine Lung Recruitability:Non-Recruitable – If PEEP is and Plateau Pressure then in an equal or greater increment.Recruitable – If PEEP is and Plateau Pressure then in a lesser increment
35 The Two We Estimate PEEP Plateau Pressure Measured but not accurate
36 The Two We Estimate: Plateau Pressure Plateau Pressure is the pressure exerted by the volume of gas in the lungs after an inhalation.Indicator of “lung fullness”Plateau Pressure Goal: Keep < 30 cmH2O
37 The Two We Estimate: Plateau Pressure Check PPLAT (with a minimum 0.5 second inspiratory pause) at least q 4h and after each change in PEEP or VT.If PPLAT >30 cmH2O:VT by 1ml/kg to minimum of 4 ml/kg.If PPLAT < 25 cmH2O and VT< 6 ml/kg: VT by 1 ml/kg until PPLAT > 25 cmH2O or VT = 6 ml/kg.If PPLAT < 30 but patient/ventilator dysynchrony is evident: VT by 1ml/kg to a VT of 7-8 ml/kg if PPLAT remains < 30 cm
39 A Brief History of the Study of Advanced Respiratory Mechanics 150 AD - Galen (Greek Physician): Postulated that lungs were expanded by the outward movement of the thorax.1817 – Carson: Attached a water manometer to the trachea of a recently-killed animal and noted an increase in tracheal pressure when the chest was opened. This he attributed to the elastic recoil of the lung.1847 – Ludwig: First to measure pleural pressure in an animal.1900 – Aron: Measured pleural pressure in a human with a chest tube.1960’s – Applicability of Esophageal Pressures to measure pleural pressures discovered.
40 Solving The Problem with Airway Pressures REMEMBER: Airway pressures displayed by ventilators do not reflect pressures within the lung but within the Entire Respiratory SystemTo truly know the pressure within the lung (Transpulmonary Pressure) it is necessary to measure and account for the pressures outside of the lung (Peripulmonary Pressures)Very difficult to directly measure pressure in the pleuraA number of historic studies have demonstrated reasonable correlation between Esophageal Pressures and Pleural PressuresPressure in the pleura adjacent to the esophagus is transmitted to the esophagus.Pressure within the pleural space is not uniformPressure in the dependent & basal regions is greater than in the upper regions of the thoracic cage
41 Solving The Problem with Airway Pressures Patients on mechanical ventilation are usually supine or semi-recumbent so it is important to account for the effect that mediastinal structures such as the heart have on esophageal pressures.Washko (2006) and Talmor (2008) have recommended that approximately 2-5 cmH2O be subtracted from the esophageal pressure to more accurately reflect pleural pressures.
42 Stiff Lung or Stiff Chest Wall? PAW = PTP + PESPAW = PTP + PES30 =30 =Gattinoni, Crit Care, Oct 2004;
43 How Common are Increased Intra-Abdominal Pressures? Total PrevalenceMICU PrevalenceSICU Prevalence>12 mmHg58.8%54.4%65%>15 mmHg28.9%29.8%27.5%>20 mmHg8.2%10.5%5.0%13 ICU’s, 6 countries, 97 patientsMalbrain et al, Intensive Care Med (2004) 30:822–829
44 Can High Intra-abdominal Pressures Really Affect Ventilation? S/P Decompressive LaparotomyRigid Abdomen in ACS
45 Transpulmonary-Guided Ventilation 3 Basic Concepts To exploit the potential for alveolar recruitment, a transpulmonary pressure that is greater than the opening pressure of the lung must be applied to the lung.To avoid alveolar collapse after recruitment, a PEEP that is greater than the compressive forces operating on the lung and alveolar ventilation that is sufficient to prevent absorption atelectasis must be provided.Avoidance of stretch (by maintaining a low plateau pressure) and prevention of cyclic collapse and reopening (by maintaining adequate PEEP and alveolar ventilation) are the physiologic cornerstones of mechanical ventilation in acute lung injury/acute respiratory distress syndrome.Gattinoni et al,CritCareMed2003Vol.31,No.4(Suppl.)
46 The Talmor/Ritz StudySurvival of ALI/ARDS patients has improved in recent years with the advent of low Vt’s and the use PEEPOptimal level of PEEP is difficult to determine.Could the use of Transpulmonary Pressure Measurements (as estimated by esophageal pressure measurements) enable the clinician to determine a PEEP value that would maintain oxygenation while preventing lung injury due to repeated alveolar collapse and/or overdistention?Mechanically-ventilated ALI/ARDS patients randomly assigned to one of two groups:CONTROL GROUP: PEEP adjusted as per ARDSNet recommendationsPES-GUIDED GROUP: PEEP was adjusted to achieve a PTP PEEP of 0 to +10 cmH2O
47 The ResultsThe primary end point of the study was improvement in oxygenation.Secondary end points respiratory-system compliance & pt outcomes.The study reached its stopping criterion and was terminated after 61 patients had been enrolled.The PaO2/FiO2 ratio at 72 hours was 88 mmHg higher in the Pes-group than in the control groupThis effect was persistent through the 24, 48 & 72 hour follow-up time.Respiratory-system compliance was also significantly improved at 24, 48, and 72 hours in the Pes-guided group
49 A Sampling of What’s in the Journals Basing ventilator settings on a maximum allowable airway plateau pressure may leave large portions of the lung under-inflated and at risk of VILI from repeated airway opening and closing.It is logical that estimating pleural pressures from PES and setting PEEP to achieve a target PTP may allow higher PEEP in many patients without overdistending lung regions that are already recruited.
50 A Sampling of What’s in the Journals Systematic use of esophageal manometry has the potential to improve ventilator management in acute respiratory failure by providing more direct assessment of lung distending pressure.
51 A Sampling of What’s in the Journals The use of airway Plateau Pressures to set ventilation may under-ventilate patients with intra-abdominal hypertension and overdistend the lungs of patients with atelectasis.Thus PTP must be used to accurately set mechanical ventilation in the critically ill.
52 A Sampling of What’s in the Journals Increases in peak airway pressure without a concomitant increase in alveolar distension are unlikely to cause damage.Critical variable is not PIP but PTPIn patients with a stiff chest wall from non-pulmonary ARDS that may have elevated pleural pressures airway Plateau Pressures may exceed 35 cmH2O without causing alveolar distension
53 A Sampling of What’s in the Journals PES can be used to estimate transpulmonary pressures that are consistent with known physiology, and can provide meaningful information, otherwise unavailable, in critically ill patients.
54 One Hospital’s Protocol for Identification of Pes Candidates Pplat > 25 cmH2OStatic Lung Compliance < 40 ml/cmH2OP/F Ratio < 300PEEP > 10 cmH2O to maintain SaO2 > 90%PaCO2 > 60 mmHg or pH < 7.2 attributable to respiratory acidosisWolfson Medical Center, Holon, Israel
55 Esophageal Balloonary: The Catheter Can utilize either a 5 or 7fr balloon-tipped catheter or a specialized NG/OG catheter that is inserted into the lower third of the esophagus, above the diaphragm.Pressures that are exerted on the balloon are measured by a transducer either integral in the ventilator or in a separate boxAn approximation of proper placement can be made by measuring the distance from the tip of the nose to the bottom of the earlobe and then from the earlobe to the distal tip of the xiphoid process of the sternum.
56 Esophageal Balloonary: Catheter Placement Properly inserted the esophageal balloon will show simultaneous negative deflections in airway and esophageal pressures during an expiratory hold during a patient-initiated breath (Baydur Method).If balloon is inserted too far into the esophagus Pes will deflect positively during a spontaneous inspiration.PES tracing may show small cardiac oscillations reflective of cardiac activity.PES should be similar (+ 10) to PGA (Bladder Pressure)Measurements should match the patients clinical presentation.
57 Esophageal Numerology: PTP PLAT Transpulmonary Pressure at End-Inspiratory PlateauIncreased abdominal pressure and/or decreased chest wall compliance is imposing a load on the lungs which is reflected in an increased pleural pressure during an inspiratory plateau.PAW PLAT = 39 cmH2OPTP PLAT = 9 cmH2OKeep PTP PLAT < 20 cmH2O
58 Esophageal Numerology: PTP PEEP Transpulmonary Pressure at End-Expiratory PlateauP AW = 15 cmH2OP ES = 10 cmH2OP TP PEEP = 5 cmH2O151010510
59 Esophageal Numerology: PTP PEEP Transpulmonary Pressure at End-Expiratory PlateauGoal is to adjust PEEP to maintain PTP PEEP between cmH2ONegative PTP PEEP = pressure outside the lung is greater than pressure inside the lung.Positive PTP PEEP = pressure inside the lung is greater than pressure outside the lungMay cause end-expiratory overdistension if too high
60 PES = PPEAK ES – PPEEP ES Esophageal Numerology: PESDelta Esophageal PressureGood indicator of Work of BreathingValues <15 cmH2O may indicate patient is a good candidate for weaning.The difference between PEAK esophageal pressure (PPEAK ES ) and BASELINE esophageal pressure (PEEPES) PES = PPEAK ES – PPEEP ESAdult Normal: 10 – 15 cm H2OPediatric Normal: 7 – 19 cm H2O
61 Esophageal Pressure Tracing Interpretation of theEsophageal Pressure TracingAnalyzing the shape of the esophageal pressure tracing may provide information regarding lung compliance.Stiff lung – airway pressures only partially transmitted to pleuraCompliant lung – airway pressures readily transmitted to pleuraClear differences between end-expiratory and end-inspiratorySorosky A, Crit Care Research and Practice
62 Case Study 1: Transpulmonary-Guided Ventilation in Increased Abdominal Pressures
63 Transpulmonary-Guided Ventilation CXR on current vent settings:Any heart silhouette?Any diaphragms?Any aeration?Esophageal Balloon insertedInitial PTP PEEP = cmH2OA negative PTP PEEP indicates the lung is being derecruited from elevated external (pleural and/or abdominal) pressures.HPX:Morbidly Obese 24 yo Female with PancreatitisSettings:PRVC-AC, RR-24, Vt-340, PEEP-7, FiO2-.45, Ti-.7ABG:pH-7.36, PaCO2-50,PaO2-57, SaO2-93%
64 Pump Up the PEEP Placed on PC/AC, RR-16, PIP-36, Ti-.70 & PEEP-20. PTP PEEP now -3.7 cmH2OSome Heart Border & Diaphragm now visible
65 Which Plateau Pressure is Correct? PAW Plateau41 cmH2OPTP PLAT21 cmH2O
66 Further PEEP Pumpage PEEP Increased to 25 cmH2O Ptp PEEP now +2.4 cmH2OLungs are remaining open at end-exhalation
67 Hey, Let’s Try APRV! PLOW of 0 PTP PEEP of -15 cmH2O IMMEDIATE Derecruitment!
68 Now What? Returned to PC/AC with PEEP of 25 cmH20 PTP PEEP now +2.4 cmH2ONo derecruitment!PAW PEAK of 46 cmH2OPTP PEAK of 27 cmH2OPhysicians were hesitant to maintain PEEP of 25
69 Now What? CXR six day post PEEP adjustment using PES monitoring PEEP 16cmH2O with FiO2 of .40Heart border and diaphragms visible
70 Case Study 2: Transpulmonary-Guided Ventilation Identifying Post-Code Derecruitment
71 PTP Pre & Post Instillation of Oleic Acid Pre-InstillationPTP PEEP = +2 cmH2ONo DerecruitmentPost-InstillationPTP PEEP = -2 cmH2ODerecruitment on PEEP of 4
72 PEEP Increased to 8 PEEP increased to 8 cmH2O PTP PEEP increased to +1.2 cmH2ODelta PES should be less than 15cm. Anything more results in increased wob. The Ptp waveform is much more important than the Paw waveform in determining what’s truly going on inside of the lungs.
73 Changes Following Resuscitative-Fluid Bolus Following multiple fluid boluses during resuscitation it was noticed that PES increased from 8 cmH2O to 12 cmH2OPTP PLAT increased to 27 cmH2OPEEP immediately increased to 10 cmH2OThis kept PTP PEEP from dropping into negativeNo “Post-Code Derecruitment”
75 Quality Requires Standardization The most meaningful cost reduction strategies will involve standardization of clinical care and elimination of variation in patient procedures May 9, 2012Before we determine what’s bad with mechanical ventilation we need to identify what is good about spontaneous ventilation. The problem is that we know very little about how the alveoli actually function during spontaneous ventilation.
76 We Need to Define Quality Q = A x (O + S)WQ – QualityA – AppropriatenessO – OutcomesS – ServiceW – WasteBefore we determine what’s bad with mechanical ventilation we need to identify what is good about spontaneous ventilation. The problem is that we know very little about how the alveoli actually function during spontaneous ventilation.
78 ReferencesMechanical Ventilation Guided by Esophageal Pressure in Acute Lung Injury, Talmor D, NEJM 2008Should Mechanical Ventilation be Guided by Esophageal Pressure Measurements?, Plataki M, Curr Op in Crit Care 2011Are Esophageal Pressure Measurements Important in Clinical Decision-Making in Mechanically Ventilated Patients?. Talmor D, Resp Care 2010Transpulmonary Pressure as a Surrogate of Plateau Pressure for Lung Protective Strategy: Not Perfect but more Physiologic, Richard JC, Int Care Med 2012Abdominal Compartment Syndrome in Patients with Isolated Extraperitoneal Injuries, Kopelman T, J Trauma 2000
79 ReferencesEsophageal and Gastric Pressure Measurement, Benditt J, Resp Care 2005Esophageal Pressure in Acute Lung Injury: do they Represent Artifact of Useful Informatinon about Transpulmonary Pressure, Chest Wall Mechanics and Lung Stress, Loring S, J Appl Physiol 2010Maintaining End-Expiratory Transpulmonary Pressure Prevents Worsening of Ventilator-Induced Lung Injury Caused by Chest Wall Constriction in Surfactant-Depleted Rate, Loring S, Crit Care Med 2010Medical Effectiveness of Esophageal Balloon Pressure Manometry in Weaning Patients from Mechanical Ventilation, Gluck E, Crit Care Med 1991Optimal PEEP Guided by Esophageal Balloon, Piraino T, AARC Open Forum AbstractPlateau and Transpulmonary Pressure with Elevated Intra-Abdominal Pressure or Atelectasis, Kubiak B, J Surg Res 2009
80 ReferencesEsophageal and Transpulmonary Pressures in Acute Respiratory Failure, Talmor D, Crit Care Med 2000Effect of Intra-Abdominal Pressure on Respiratory Mechanics, Pelois P, Acta Clinica Belgica 2007What is Normal Intra-Abdomial Pressure and how is it Affected by Positioning, Body Mass and Positive End-Expiratory Pressure?, DeKeulenaer B, Int Care Med 2009Targeting Tranpsulmonhary Pressure to Prevent Ventilator Induced Lung Injury, Talmor D, Min Anest 2009BiCor Directed Weaning Reduces Ventilator Days, ICU Stay, Length of Hospitalization, and Cost of Care, Rouben L, Chest 1996Effects of Positive End-Expiratory Pressure on Respiratory Function and Hemodynamics in patients with Acute Respiratory Failre with and without Intra-Abdominal Hypertension: a Pilot Study, Krebs J, Crit Care 2009
81 ReferencesRefocusing on Transpulmonary Pressure, Marini, Focus Journal 2010Respiratory Restriction and Elevated Pleural and Esophageal Pressures in Morbid Obesity, Behazin N, J Appl Physiol 2010Weaning Prediction: Esophageal Pressure Monitoring Compliments Readiness Testing, Jubran A, Am J Respir Crit Care Med 2005The use of Transpulmonary Pressure to Set Optimal Positive End-Expiratory Pressure: A Case Report, Piraino T, Can J Resp Ther 2010Goal-Directed Mechanical Ventilation: Are We Aiming at the Right Goals? A Proposal for an Alternative Approach Aiming at Optimal Lung Compliance, Guided by Esophageal Pressure in ARDS, Sorosky A, Critical Care Research and Practice 2012