Effect of PEEP on Dead Space in an Experimental Model of ARDS

Tusman, Gerardo; Gogniat, Emiliano; Madorno, Matías; Otero, Pablo E.; Dianti, José; Ceballos, Ignacio Fernández; Ceballos, Martin R; Verdier, Natalí; Böhm, Stephan H.; Rodríguez, Pablo; Román, Eduardo San

doi:10.4187/respcare.06843

Cited by 14 publications

(6 citation statements)

References 39 publications

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“…In order to reproduce an experimental ARDS model in one pig of the pair, lung lavages with normal saline (30 mL/kg at 37°C) were performed. Guided by the evaluation of lung aeration and SpO 2 , lavages were repeated until PaO 2 /FiO 2 < 200 mm Hg at PEEP 10 cm H 2 O, as previously reported by Tusman et al [ 12 ]. Both paired units were continuously ventilated in dual mode for eight hours.…”

Section: Methodsmentioning

confidence: 99%

Ventilator output splitting interface ‘ACRA’: Description and evaluation in lung simulators and in an experimental ARDS animal model

et al. 2021

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The current COVID-19 pandemic has led the world to an unprecedented global shortage of ventilators, and its sharing has been proposed as an alternative to meet the surge. This study outlines the performance of a preformed novel interface called ’ACRA’, designed to split ventilator outflow into two breathing systems. The ’ACRA’ interface was built using medical use approved components. It consists of four unidirectional valves, two adjustable flow-restrictor valves placed on the inspiratory limbs of each unit, and one adjustable PEEP valve placed on the expiratory limb of the unit that would require a greater PEEP. The interface was interposed between a ventilator and two lung units (phase I), two breathing simulators (phase II) and two live pigs with heterogeneous lung conditions (phase III). The interface and ventilator adjustments tested the ability to regulate individual pressures and the resulting tidal volumes. Data were analyzed using Friedman and Wilcoxon tests test (p < 0.05). Ventilator outflow splitting, independent pressure adjustments and individual tidal volume monitoring were feasible in all phases. In all experimental measurements, dual ventilation allowed for individual and tight adjustments of the pressure, and thus volume delivered to each paired lung unit without affecting the other unit’s ventilation—all the modifications performed on the ventilator equally affected both paired lung units. Although only suggested during a dire crisis, this experiment supports dual ventilation as an alternative worth to be considered.

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Section: Methodsmentioning

confidence: 99%

Ventilator output splitting interface ‘ACRA’: Description and evaluation in lung simulators and in an experimental ARDS animal model

et al. 2021

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“…This is rather laborious and measuring lung compliance at different PEEP levels after lung recruitment could be a suitable simplification of this method. Calculating dead space and shunt fraction was also used for PEEP selection ( Ferluga et al, 2018 ; Karbing et al, 2020 ; Tusman et al, 2020 ). Recently, measuring potential recruitment has also been proposed ( Chen et al, 2020 ).…”

Section: Lung Physiology In Human Subjects: Mechanical Ventilation An...mentioning

confidence: 99%

Lung Mechanics Over the Century: From Bench to Bedside and Back to Bench

et al. 2022

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Lung physiology research advanced significantly over the last 100 years. Respiratory mechanics applied to animal models of lung disease extended the knowledge of the workings of respiratory system. In human research, a better understanding of respiratory mechanics has contributed to development of mechanical ventilators. In this review, we explore the use of respiratory mechanics in basic science to investigate asthma and chronic obstructive pulmonary disease (COPD). We also discuss the use of lung mechanics in clinical care and its role on the development of modern mechanical ventilators. Additionally, we analyse some bench-developed technologies that are not in widespread use in the present but can become part of the clinical arsenal in the future. Finally, we explore some of the difficult questions that intensive care doctors still face when managing respiratory failure. Bringing back these questions to bench can help to solve them. Interaction between basic and translational science and human subject investigation can be very rewarding, as in the conceptualization of “Lung Protective Ventilation” principles. We expect this interaction to expand further generating new treatments and managing strategies for patients with respiratory disease.

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“…(*) p < 0.05 compared to best PEEP. 30 cmH 2 O were analyzed in an experimental model of ARDS (Tusman et al, 2020). The Bohr's VD, with both its airway and alveolar components, increased in proportion when PEEP exceeded 15 cmH 2 O, reflecting clear global lung overdistension that was confirmed by a parallel decrease in CO 2 elimination by the lungs, an increase in lung elastance, transpulmonary DP, and end-inspiratory transpulmonary pressure (Figure 4).…”

Section: Evaluation Of Lung Overdistension By Volumetric Capnographymentioning

confidence: 99%

“…Panel (A) shows the effect of PEEP on absolute dead space values. Panels (B,C) present the differences in alveolar dead space ( VD alv ), elimination of CO 2 per breath ( VTCO 2,br ), transpulmonary driving pressure ( DPtp), transpulmonary end-inspiratory pressure ( Ptp insp ), and lung elastance ( E L ) between certain PEEP level with the reference15-PEEP considered as the "Best" PEEP according to findings in gas exchange, lung ultrasound, and respiratory mechanics adapted fromTusman et al (2020).…”

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Monitoring Expired CO2 Kinetics to Individualize Lung-Protective Ventilation in Patients With the Acute Respiratory Distress Syndrome

et al. 2021

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Mechanical ventilation (MV) is a lifesaving supportive intervention in the management of acute respiratory distress syndrome (ARDS), buying time while the primary precipitating cause is being corrected. However, MV can contribute to a worsening of the primary lung injury, known as ventilation-induced lung injury (VILI), which could have an important impact on outcome. The ARDS lung is characterized by diffuse and heterogeneous lung damage and is particularly prone to suffer the consequences of an excessive mechanical stress imposed by higher airway pressures and volumes during MV. Of major concern is cyclic overdistension, affecting those lung segments receiving a proportionally higher tidal volume in an overall reduced lung volume. Theoretically, healthier lung regions are submitted to a larger stress and cyclic deformation and thus at high risk for developing VILI. Clinicians have difficulties in detecting VILI, particularly cyclic overdistension at the bedside, since routine monitoring of gas exchange and lung mechanics are relatively insensitive to this mechanism of VILI. Expired CO2 kinetics integrates relevant pathophysiological information of high interest for monitoring. CO2 is produced by cell metabolism in large daily quantities. After diffusing to tissue capillaries, CO2 is transported first by the venous and then by pulmonary circulation to the lung. Thereafter diffusing from capillaries to lung alveoli, it is finally convectively transported by lung ventilation for its elimination to the atmosphere. Modern readily clinically available sensor technology integrates information related to pulmonary ventilation, perfusion, and gas exchange from the single analysis of expired CO2 kinetics measured at the airway opening. Current volumetric capnography (VCap), the representation of the volume of expired CO2 in one single breath, informs about pulmonary perfusion, end-expiratory lung volume, dead space, and pulmonary ventilation inhomogeneities, all intimately related to cyclic overdistension during MV. Additionally, the recently described capnodynamic method provides the possibility to continuously measure the end-expiratory lung volume and effective pulmonary blood flow. All this information is accessed non-invasively and breath-by-breath helping clinicians to personalize ventilatory settings at the bedside and minimize overdistension and cyclic deformation of lung tissue.

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Effect of PEEP on Dead Space in an Experimental Model of ARDS

Cited by 14 publications

References 39 publications

Ventilator output splitting interface ‘ACRA’: Description and evaluation in lung simulators and in an experimental ARDS animal model

Ventilator output splitting interface ‘ACRA’: Description and evaluation in lung simulators and in an experimental ARDS animal model

Lung Mechanics Over the Century: From Bench to Bedside and Back to Bench

Monitoring Expired CO2 Kinetics to Individualize Lung-Protective Ventilation in Patients With the Acute Respiratory Distress Syndrome

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