Advanced Ventilator Management Transpulmonary Guided V entilation

ADVANCED VENTILATOR

MANAGEMENT

Transpulmonary Guided

VentilationThom Petty BS RRT

Lead Clinical Specialist – East CareFusion Critical Care Ventilation

Objectives

Identify 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 ventilation

Introduce 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.

Basic Ventilator

Mechanics

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)

Mechanics 101: Motion of Air Equation

PRESSURE IN THE AIRWAY (PAW) Measured at the circuit wye Not the actual pressure in the lungs but the

pressure of the entire respiratory system Reflects both lung and pleural pressures

PERI-PULMONARY/PLEURAL PRESSURE (PES) Pressure that is imposed upon the lungs by

the Chest Wall and Abdomen Can be approximated by measuring

pressures within the Esophagus

PRESSURE WITHIN THE ALVEOLI (PTP) The TRUE pressure within the lung PTP = PAW – PES

As the Lung Inflates

Paw

Pes Ptp

Inspiratory Hold Measures the Plateau Pressure of the entire Respiratory System

Indicator of end-inspiratory lung distension

Static Compliance Reflects the compliance of the entire Respiratory System

Expiratory Hold Measures the amount of intrinsic PEEP of the entire Respiratory System

Our Current Respiratory Mechanics Toolbox

MECHA

NICAL

VENTIL

ATION?

What’s so bad about

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

The Hazard that is Mechanical Ventilation

8

Just What is Positive-Pressure Ventilation?

Just what is it that is delivered by the ventilator to the patients’ lungs?

Volume

Flow

Pressure

The Alveoli – Not Grapes on a Straw

The Alveolar Structure

Adjacent alveoli and terminal bronchioles share common walls

Forces 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.

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 folding

Alveoli in ALI: Undergo large changes in alveolar size Widespread alveolar recruitment/derecruitment predominate. Can cause significant shear stress-induced lung injury Gross tearing of the alveolar wall Injury to the cell membrane Ultrastructural injury

Wilson, J Appl Physiol, 2001Carney, CCM, 2005

Steinberg, AJRCCM, 2004

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 lung Flow is attenuated in low-compliant areas

This heterogenocity can result in overdistension of compliant “healthy” lung and underdistension of non-compliant “injured” lung

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 barotrauma

However, 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

Ventilator-Induced Lung InjuryVolutrauma & Inflammation

Study investigating the release of “Lung Flooding” factors in Rodents ventilated with three modes:

HiP/HiV High Pressure (45 cmH2O) High Volume

LoP/HiV Low Pressure (neg.pres.vent) High Volume

HiP/LoV High Pressure (45 cmH2O) Low Volume (chest bound)

Dreyfuss,D ARRD 1988;137:1159

Mechanical and Biochemical in nature

Caused by excessive End-Inspiratory Volumes Indicated by elevated end-inspiratory (Plateau) pressures May result from a combination of “Safe” Vt + PEEP

Even “safe” Vt’s may severely over-inflate normal alveoli due to heterogenicity of airflow within the lung

QUESTION: How can a clinician determine if alveoli are over-distended at end-inspiration?

Ventilator-Induced Lung InjuryTake-Home Points - Volutrauma

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-6 Interleukin-11 Interleukin-γ Tissue Necrosis Factor-α

Ventilator-Induced Lung InjuryAtelectrauma

Associated with repeated opening and closing of alveoli during ventilatory phasing

Associated with regional differences in ventilation

Worsens surfactant dysfunction

Release of inflammatory mediators into alveolar spaces and into the systemic circulation

QUESTION: How can the clinician determine what PEEP is necessary to keep the alveoli open at end-exhalation

Ventilator-Induced Lung InjuryTake-home Points - Atelectrauma

Presumed Mechanism for VILI

Mechanical Disruption of Pulmonary Epithelium

Mechanotransduction Cell & Tissue Disruption

Upregulation & release of Cytokines &, Chemokines

Subsequent leucocyte attraction and activation

Pulmonary Inflammation: VILI

Systemic Spillover:SIRS / MODS

MECHANOTRANSDUCTION – Conversion of Mechanical Stimiuls into Chemical ReactionSIRS – systemic inflammatory Response SyndromeMODS – Multi Organ Dysfunction syndrome

Lung-Protective Ventilation

Safer Ventilator Management

Lung-Protective Ventilation Theory

1987 - 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 limitation Modest PEEP & Plateau pressures

The 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.

Lung-Protective Ventilation Research

There have been six randomized controlled trials evaluating the effect of lung-protective ventilation in comparison with conventional approaches:

1988 Amato et al Brazil

29 pts: Vt < 6ml/kg, Pplat < 20cmH2O24 pts: Vt = 12ml/kg, PaCO2 35-38 mmHg

38% Mortality71% Mortality

1998 Stewart et alCanada

60 pts: Vt < 8ml/kg, Ppeak < 30cmH2O60 pts: Vt 10-15ml/kg, Ppeak < 50cmH2O

50% Mortality at disch47% Mortality at disch

1998 Brochard et alMultinational

58 pts: Vt 6-10ml/kg, Pplat < 25-30 cmH2O58 pts: Vt 10-15ml/kg, PaCO2 38-42 mmHg

47% Mortality at 60 days38% Mortality at 60 days

1999 Brower et alUSA

26 pts: Vt 5-8ml/kg, Pplat <30 cmH2O26 pts: Vt 10-12ml/kg, Pplat < 45-55 cmH2O


2000 ARDSnetworkUSA

432 pts: Vt 6ml/kg, Pplat < 30 cmH2O429 pts: Vt 12ml/kg, Pplat < 50 cmH2O

31% Mortality at disch/180 d40% Mortality at disch/180 d

2006 Villar et alSpain

50 pts: Vt 5-8ml/kg, PEEP @ LIP + 2cmH2O53 pts: Vt 9-11ml/kg, PEEP >5 cmH2O

32% Mortality in ICU53% Mortality in ICU

The Handful of Ventilator Settings

Tidal Volume Accurately measured

Respiratory RateAccurately measured

FiO2 Accurately measured

PEEP Measured but not accurate

Plateau PressureMeasured but not accurate

A key limitation to mechanical ventilators is that they report peak airway pressures

without distinguishing compliance that reflects intrinsic lung mechanics or chest wall

and abdominal pressures

Piraino T, Respiratory Care, April 2011

The Problem with Airway Pressures

The Two Settings We Estimate



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 benefits

Use of PEEP < 10cmH2O leads to an increase in mortalityAmato M., 8th World Congress, Sydney, Australia

Dreyfuss, Crit Care Med, 1998Gattinoni, NEJM, 2006

Muscedere , Am J Respir Crit Care Med. 1994

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-Analysis Differences in hospital mortality not statically significant Significant reduction of death in the ICU in the High PEEP group

2004ARDSNetALVEOLIUSA

276 pts: Mean PEEP = 14.7cmH2O273 pts: Mean PEEP = 8.9cmH2O

25% Mortality at disch27.5% Mortality at disch

2008MeadeLOVSMultinational



2008MercatEXPRESSFrance


35% Mortality at 60 days39% Mortality at 60 days

Low PEEP/High FiO2 ProtocolFiO2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.7 0.7 0.8 0.9 0.9 0.9 1.0PEEP 5 5 8 8 10 10 10 12 14 14 14 16 16 18-24

High PEEP/Low FiO2 ProtocolFiO2 0.3 0.3 0.3 0.3 0.3 0.4 0.4 0.5 0.5 0.5-0.8 0.8 0.9 1.0 1.0PEEP 5 8 10 12 14 14 16 16 18 20 22 22 22 24

The Two we Estimate: The PEEP Controversy

The Two we Estimate: Optimal PEEP

• Ideal PEEP is defined as:

• High enough to induce alveolar recruitment, keeping the lung more aerated at end-exhalation, while not distending “good”alveoli

• Low enough to prevent hemodynamic impairment & overdistension

PEEP TABLE Table of FiO2 & PEEP combinations to achieve PaO2 or SpO2 in target range

MAXIMAL PEEP WITHOUT OVERDISTENSION

Use of highest PEEP while maintaining Pplat < 30 cmH2O

GAS EXCHANGE Lowest shunt (highest PaO2), lowest deadspace (lowest PaCO2), best oxygen delivery (CaO2 x C.O.)

COMPLIANCE Use of the highest PEEP that results in the highest respiratory-system compliance

STRESS INDEX Observe the Pressure/Time Curve during constant flow inhalation for signs of tidal recruitment and overdistension

PRESSURE/VOLUME CURVE Set PEEP slightly higher than Lower Inflection Point

IMAGING Computed tomography, Electrical impedence tomography, Ultrasound

ESOPHAGEAL PRESSURE MONITORING

Estimate the intra-pleural pressure with the measurement of Esophageal Pressure then determine optimal PEEP

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 recruitability• In ALI/ARDS patients with low potential for recruitment, the

resulting over-distension associated with PEEP increases was harmful

• How 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

The Two We Estimate



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

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

Transpulmonary Guided

Ventilation

REMEMBER: Airway pressures displayed by ventilators do not reflect pressures within the lung but within the Entire Respiratory System

To 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 pleura

A number of historic studies have demonstrated reasonable correlation between Esophageal Pressures and Pleural Pressures Pressure in the pleura adjacent to the esophagus is transmitted to the

esophagus. Pressure within the pleural space is not uniform Pressure in the dependent & basal regions is greater than in the

upper regions of the thoracic cage

Solving The Problem with Airway Pressures

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.

Stiff Lung or Stiff Chest Wall?

30 = 15 + 1530 = 25 + 5PAW = PTP + PES

Gattinoni, Crit Care, Oct 2004;

PAW = PTP + PES

How Common are Increased Intra-Abdominal Pressures?

Malbrain et al, Intensive Care Med (2004) 30:822–829

Abdominal Pressure Total Prevalence MICU Prevalence SICU Prevalence

>12 mmHg 58.8% 54.4% 65%

>15 mmHg 28.9% 29.8% 27.5%

>20 mmHg 8.2% 10.5% 5.0%

13 ICU’s, 6 countries, 97 patients

Can High Intra-abdominal Pressures Really Affect Ventilation?

Rigid Abdomen in ACS S/P Decompressive Laparotomy

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.)

Transpulmonary-Guided Ventilation3 Basic Concepts

45

The Talmor/Ritz Study

Survival of ALI/ARDS patients has improved in recent years with the advent of low Vt’s and the use PEEP Optimal 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 recommendations PES-GUIDED GROUP: PEEP was adjusted to achieve a PTP PEEP of 0 to

+10 cmH2O

The Results

• The 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 group

• This 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

Outcomes

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.

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.


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.


Increases in peak airway pressure without a concomitant increase in alveolar distension are unlikely to cause damage. Critical variable is not PIP but PTP

In 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


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.


Pplat > 25 cmH2O

Static Lung Compliance < 40 ml/cmH2O

P/F Ratio < 300

PEEP > 10 cmH2O to maintain SaO2 > 90%

PaCO2 > 60 mmHg or pH < 7.2 attributable to respiratory acidosis

Wolfson Medical Center, Holon, Israel

One Hospital’s Protocol for Identification of Pes Candidates

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 box

An 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.

Esophageal Balloonary: The Catheter

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.

Esophageal Balloonary: Catheter Placement

Increased 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 cmH2O PTP PLAT = 9 cmH2O

Keep PTP PLAT < 20 cmH2O

Esophageal Numerology: PTP PLATTranspulmonary Pressure at End-Inspiratory Plateau

P AW = 15 cmH2OP ES = 10 cmH2OP TP PEEP = 5 cmH2O

10

15

5

1010

Esophageal Numerology: PTP PEEPTranspulmonary Pressure at End-Expiratory Plateau

Esophageal Numerology: PTP PEEPTranspulmonary Pressure at End-Expiratory Plateau

Goal is to adjust PEEP to maintain PTP PEEP between 0 - +2 cmH2O

Negative 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 lung

May cause end-expiratory overdistension if too high

Good indicator of Work of Breathing Values <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 ES

Adult Normal: 10 – 15 cm H2O Pediatric Normal: 7 – 19 cm H2O

Esophageal Numerology: PESDelta Esophageal Pressure

Analyzing the shape of the esophageal pressure tracing may provide information regarding lung compliance.

Stiff lung – airway pressures only partially transmitted to pleura Compliant lung – airway pressures readily transmitted to pleura Clear differences between end-expiratory and end-inspiratory

Interpretation of the Esophageal Pressure Tracing

Sorosky A, Crit Care Research and Practice

Case Study 1:Transpulmonary-Guided Ventilation

in Increased Abdominal Pressures

Transpulmonary-Guided Ventilation

HPX: Morbidly Obese 24 yo

Female with Pancreatitis

Settings: PRVC-AC, RR-24, Vt-

340, PEEP-7, FiO2-.45, Ti-.7

ABG: pH-7.36, PaCO2-50, PaO2-57, SaO2-93%

• CXR on current vent settings:• Any heart silhouette?• Any diaphragms?• Any aeration?

• Esophageal Balloon inserted • Initial PTP PEEP = -12.3 cmH2O• A negative PTP PEEP indicates the

lung is being derecruited from elevated external (pleural and/or abdominal) pressures.

Placed on PC/AC, RR-16, PIP-36, Ti-.70 & PEEP-20.

PTP PEEP now -3.7 cmH2O

Some Heart Border & Diaphragm now visible

Pump Up the PEEP

• PAW Plateau• 41 cmH2O

• PTP PLAT

• 21 cmH2O

Which Plateau Pressure is Correct?

• PEEP Increased to 25 cmH2O

• Ptp PEEP now +2.4 cmH2O• Lungs are remaining

open at end-exhalation

Further PEEP Pumpage

Hey, Let’s Try APRV!

• PLOW of 0

• PTP PEEP of -15 cmH2O

• IMMEDIATE Derecruitment!

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 cmH2O

Physicians were hesitant to maintain PEEP of 25

CXR six day post PEEP adjustment using PES monitoring PEEP 16cmH2O with FiO2 of .40 Heart border and diaphragms visible

Now What?

Case Study 2:Transpulmonary-Guided Ventilation

Identifying Post-Code Derecruitment

PTP Pre & Post Instillation of Oleic Acid

• Pre-Instillation• PTP PEEP = +2 cmH2O• No Derecruitment

• Post-Instillation• PTP PEEP = -2 cmH2O• Derecruitment on

PEEP of 4

PEEP Increased to 8

• PEEP increased to 8 cmH2O

• PTP PEEP increased to +1.2 cmH2O

Changes Following Resuscitative-Fluid Bolus

• Following multiple fluid boluses during resuscitation it was noticed that PES increased from 8 cmH2O to 12 cmH2O

• PTP PLAT increased to 27 cmH2O

• PEEP immediately increased to 10 cmH2O

• This kept PTP PEEP from dropping into negative• No “Post-Code

Derecruitment”

One Last Point

Quality Requires Standardization

The most meaningful cost reduction strategies will involve standardization of clinical care and elimination of variation in patient procedures.

May 9, 2012

We Need to Define Quality

Q = A x (O + S) W

Q – QualityA – AppropriatenessO – OutcomesS – ServiceW – Waste

Questions?

Email: [email protected]

References

Mechanical Ventilation Guided by Esophageal Pressure in Acute Lung Injury, Talmor D, NEJM 2008

Should Mechanical Ventilation be Guided by Esophageal Pressure Measurements?, Plataki M, Curr Op in Crit Care 2011

Are Esophageal Pressure Measurements Important in Clinical Decision-Making in Mechanically Ventilated Patients?. Talmor D, Resp Care 2010

Transpulmonary Pressure as a Surrogate of Plateau Pressure for Lung Protective Strategy: Not Perfect but more Physiologic, Richard JC, Int Care Med 2012

Abdominal Compartment Syndrome in Patients with Isolated Extraperitoneal Injuries, Kopelman T, J Trauma 2000

78

References

Esophageal and Gastric Pressure Measurement, Benditt J, Resp Care 2005

Esophageal 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 2010

Maintaining 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 2010

Medical Effectiveness of Esophageal Balloon Pressure Manometry in Weaning Patients from Mechanical Ventilation, Gluck E, Crit Care Med 1991

Optimal PEEP Guided by Esophageal Balloon, Piraino T, AARC Open Forum Abstract

Plateau and Transpulmonary Pressure with Elevated Intra-Abdominal Pressure or Atelectasis, Kubiak B, J Surg Res 2009

79

References

Esophageal and Transpulmonary Pressures in Acute Respiratory Failure, Talmor D, Crit Care Med 2000

Effect of Intra-Abdominal Pressure on Respiratory Mechanics, Pelois P, Acta Clinica Belgica 2007

What is Normal Intra-Abdomial Pressure and how is it Affected by Positioning, Body Mass and Positive End-Expiratory Pressure?, DeKeulenaer B, Int Care Med 2009

Targeting Tranpsulmonhary Pressure to Prevent Ventilator Induced Lung Injury, Talmor D, Min Anest 2009

BiCor Directed Weaning Reduces Ventilator Days, ICU Stay, Length of Hospitalization, and Cost of Care, Rouben L, Chest 1996

Effects 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

80

References

Refocusing on Transpulmonary Pressure, Marini, Focus Journal 2010

Respiratory Restriction and Elevated Pleural and Esophageal Pressures in Morbid Obesity, Behazin N, J Appl Physiol 2010

Weaning Prediction: Esophageal Pressure Monitoring Compliments Readiness Testing, Jubran A, Am J Respir Crit Care Med 2005

The use of Transpulmonary Pressure to Set Optimal Positive End-Expiratory Pressure: A Case Report, Piraino T, Can J Resp Ther 2010

Goal-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

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Advanced Ventilator Management Transpulmonary Guided V entilation