Time-controlled adaptive ventilation (TCAV) accelerates simulated mucus clearance via increased expiratory flow rate

Mahajan, Melissa; DiStefano, David; Satalin, Joshua; Andrews, Penny; Al-Khalisy, Hassan; Baker, S.; Gatto, Louis A.; Nieman, Gary F.; Habashi, Nader M.

doi:10.1186/s40635-019-0250-5

Cited by 10 publications

(8 citation statements)

References 19 publications

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“…A similar study found a PEFR target of 75% during T-low resulted in the least alveolar microstrain (107). In other animal models, APRV has had a favorable effect on dynamic alveolar homogeneity (108) and has also led to improved mucous clearance (109). APRV was found to reduce inflammation and pulmonary edema in a rabbit model of ARDS (110).…”

Section: Animal Modelsmentioning

confidence: 81%

A narrative review of advanced ventilator modes in the pediatric intensive care unit

Miller¹,

Bartle²,

Feldman³

et al. 2021

Transl Pediatr

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Respiratory failure is a common reason for pediatric intensive care unit admission. The vast majority of children requiring mechanical ventilation can be supported with conventional mechanical ventilation (CMV) but certain cases with refractory hypoxemia or hypercapnia may require more advanced modes of ventilation. This paper discusses what we have learned about the use of advanced ventilator modes [e.g., high-frequency oscillatory ventilation (HFOV), high-frequency percussive ventilation (HFPV), high-frequency jet ventilation (HFJV) airway pressure release ventilation (APRV), and neurally adjusted ventilatory assist (NAVA)] from clinical, animal, and bench studies. The evidence supporting advanced ventilator modes is weak and consists of largely of single center case series, although a few RCTs have been performed. Animal and bench models illustrate the complexities of different modes and the challenges of applying these clinically. Some modes are proprietary to certain ventilators, are expensive, or may only be available at well-resourced centers. Future efforts should include large, multicenter observational, interventional, or adaptive design trials of different rescue modes (e.g., PROSpect trial), evaluate their use during ECMO, and should incorporate assessments through volumetric capnography, electric impedance tomography, and transpulmonary pressure measurements, along with precise reporting of ventilator parameters and physiologic variables.

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Section: Animal Modelsmentioning

confidence: 81%

A narrative review of advanced ventilator modes in the pediatric intensive care unit

Miller¹,

Bartle²,

Feldman³

et al. 2021

Transl Pediatr

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“…In lungs with global edema, accelerated deflation also led to release of fluid from flooded alveoli, but the fluid redistributed to neighboring alveoli due to the higher surface tension, with no improvement in flooding heterogeneity (Wu et al, 2017). The importance of accelerated deflation on mucous clearance has similarly been described in a porcine lung model and represents a ventilator setting that may alter the lung micro-environment (Mahajan et al, 2019).…”

Section: Alveolar Edemamentioning

confidence: 88%

Mechanical Ventilation Lessons Learned From Alveolar Micromechanics

et al. 2020

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Morbidity and mortality associated with lung injury remains disappointingly unchanged over the last two decades, in part due to the current reliance on lung macro-parameters set on the ventilator instead of considering the micro-environment and the response of the alveoli and alveolar ducts to ventilator adjustments. The response of alveoli and alveolar ducts to mechanical ventilation modes cannot be predicted with current bedside methods of assessment including lung compliance, oxygenation, and pressurevolume curves. Alveolar tidal volumes (Vt) are less determined by the Vt set on the mechanical ventilator and more dependent on the number of recruited alveoli available to accommodate that Vt and their heterogeneous mechanical properties, such that high lung Vt can lead to a low alveolar Vt and low Vt can lead to high alveolar Vt. The degree of alveolar heterogeneity that exists cannot be predicted based on lung calculations that average the individual alveolar Vt and compliance. Finally, the importance of time in promoting alveolar stability, specifically the inspiratory and expiratory times set on the ventilator, are currently under-appreciated. In order to improve outcomes related to lung injury, the respiratory physiology of the individual patient, specifically at the level of the alveolus, must be targeted. With experimental data, this review highlights some of the known mechanical ventilation adjustments that are helpful or harmful at the level of the alveolus.

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“…Indeed, our work in translational animal models and a meta-analysis of data on surgical intensive care unit (SICU) patients has shown that our time-controlled adaptive ventilation (TCAV) method, using airway pressure release ventilation (APRV) mode, is highly effective at keeping the lung open and stable, significantly reducing morbidity in translational animal models and reducing the ARDS incidence and mortality rates of SICU patients at high risk of developing ARDS (Roy et al, 2012;Andrews et al, 2013;Emr et al, 2013;Roy S.K. et al, 2013;Kollisch-Singule et al, 2014a,b, 2015aNieman et al, Nieman et al, 2015, 2017aSmith et al, 2015;Jain et al, 2016Jain et al, , 2017Satalin et al, 2018;Silva et al, 2018;Mahajan et al, 2019).…”

Section: A Physiologically Informed Strategy To Effectively Open and mentioning

confidence: 99%

A Physiologically Informed Strategy to Effectively Open, Stabilize, and Protect the Acutely Injured Lung

et al. 2020

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Acute respiratory distress syndrome (ARDS) causes a heterogeneous lung injury and remains a serious medical problem, with one of the only treatments being supportive care in the form of mechanical ventilation. It is very difficult, however, to mechanically ventilate the heterogeneously damaged lung without causing secondary ventilatorinduced lung injury (VILI). The acutely injured lung becomes time and pressure dependent, meaning that it takes more time and pressure to open the lung, and it recollapses more quickly and at higher pressure. Current protective ventilation strategies, ARDSnet low tidal volume (LVt) and the open lung approach (OLA), have been unsuccessful at further reducing ARDS mortality. We postulate that this is because the LVt strategy is constrained to ventilating a lung with a heterogeneous mix of normal and focalized injured tissue, and the OLA, although designed to fully open and stabilize the lung, is often unsuccessful at doing so. In this review we analyzed the pathophysiology of ARDS that renders the lung susceptible to VILI. We also analyzed the alterations in alveolar and alveolar duct mechanics that occur in the acutely injured lung and discussed how these alterations are a key mechanism driving VILI. Our analysis suggests that the time component of each mechanical breath, at both inspiration and expiration, is critical to normalize alveolar mechanics and protect the lung from VILI. Animal studies and a meta-analysis have suggested that the time-controlled adaptive ventilation (TCAV) method, using the airway pressure release ventilation mode, eliminates the constraints of ventilating a lung with heterogeneous injury, since it is highly effective at opening and stabilizing the time-and pressure-dependent lung. In animal studies it has been shown that by "casting open" the acutely injured lung with TCAV we can (1) reestablish normal expiratory lung volume as assessed by direct observation of subpleural alveoli; (2) return normal parenchymal microanatomical structural support, known as alveolar interdependence and parenchymal tethering, as assessed by morphometric analysis of lung histology; (3) facilitate regeneration of normal surfactant function measured as increases in surfactant proteins A and B; and (4) significantly increase lung compliance, which reduces the pathologic impact of driving pressure and mechanical power at any given tidal volume.

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Time-controlled adaptive ventilation (TCAV) accelerates simulated mucus clearance via increased expiratory flow rate

Cited by 10 publications

References 19 publications

A narrative review of advanced ventilator modes in the pediatric intensive care unit

A narrative review of advanced ventilator modes in the pediatric intensive care unit

Mechanical Ventilation Lessons Learned From Alveolar Micromechanics

A Physiologically Informed Strategy to Effectively Open, Stabilize, and Protect the Acutely Injured Lung

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