Role of Strain Rate in the Pathogenesis of Ventilator-Induced Lung Edema*

Protti, Alessandro; Maraffi, Tommaso; Milesi, M.; Votta, Emiliano; Santini, Alessandro; Pugni, Paola; Andreis, Davide T.; Nicosia, Francesco M.; Zannin, Emanuela; Gatti, Stefano; Vaira, Valentina; Ferrero, Stefano; Gattinoni, Luciano

doi:10.1097/ccm.0000000000001718

Cited by 117 publications

(101 citation statements)

References 37 publications

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“…In addition, we found that the tidal strain was more related to injury than the static strain (40). Further, we found that, for the same tidal volume, the rate of its delivery (i.e., the flow) was also a possible determinant of VILI (24). Given these experimental data, we realized that the cause of VILI could be described as a single physical entity (i.e., the mechanical power), which combines volume, pressures, flow and respiratory rate (22).…”

Section: Mechanical Powermentioning

confidence: 86%

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Driving pressure and mechanical power: new targets for VILI prevention

et al. 2017

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Several factors have been recognized as possible triggers of ventilator-induced lung injury (VILI).The first is pressure (thus the 'barotrauma'), then the volume (hence the 'volutrauma'), finally the cyclic opening-closing of the lung units ('atelectrauma'). Less attention has been paid to the respiratory rate and the flow, although both theoretical considerations and experimental evidence attribute them a significant role in the generation of VILI. The initial injury to the lung parenchyma is necessarily mechanical and it could manifest as an unphysiological distortion of the extracellular matrix and/or as micro-fractures in the hyaluronan, likely the most fragile polymer embedded in the matrix. The order of magnitude of the energy required to break a molecular bond between the hyaluronan and the associated protein is 1.12×10 -16 Joules (J), 70-90% higher than the average energy delivered by a single breath of 1L assuming a lung elastance of 10 cmH 2 O/L (0.5 J). With a normal statistical distribution of the bond strength some polymers will be exposed each cycle to an energy large enough to rupture. Both the extracellular matrix distortion and the polymer fractures lead to inflammatory increase of capillary permeability with edema if a pulmonary blood flow is sufficient. The mediation analysis of higher vs. lower tidal volume and PEEP studies suggests that the driving pressure, more than tidal volume, is the best predictor of VILI, as inferred by increased mortality. This is not surprising, as both tidal volume and respiratory system elastance (resulting in driving pressure) may independently contribute to the mortality. For the same elastance driving pressure is a predictor similar to plateau pressure or tidal volume. Driving pressure is one of the components of the mechanical power, which also includes respiratory rate, flow and PEEP. Finding the threshold for mechanical power would greatly simplify assessment and prevention of VILI.

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Section: Mechanical Powermentioning

confidence: 86%

“…However, both theoretical considerations (22,23) and experimental evidence (24) suggest that during mechanical ventilation the importance of flow cannot be neglected. Indeed, the flow may be considered as the rate at which a given strain occurs into the lung.…”

Section: Flowmentioning

confidence: 99%

Driving pressure and mechanical power: new targets for VILI prevention

et al. 2017

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“…Excessive stretch, strain, and tidal opening and closure may all be important, but the precise mechanism through which they act remains unclear. Dynamic characteristics-frequency, flow rate, strain rate-have recently been emphasized as key determinants of whether the 'static' variables inflict injury [2]. In this issue, Gattinoni and colleagues present an elegant and persuasive argument that energy delivered per unit time ('power') is a unifying entity into which most key ventilator settings and forces relevant to VILI can be channeled, thus providing a "composite index" by which to translate this insight into clinical practice [3].…”

mentioning

confidence: 99%

“…The excursion of tidal pressure (DP) appears to be more important than the maximum (plateau) pressure applied [1], and the frequency of potentially injurious cycling helps determine tissue damage [6]. Flow rate and profile, clinically adjustable variables often de-emphasized in the lung protective strategy, have also been shown to be influential, even when plateau and driving pressures remain constant [2,7]. Whether raising PEEP proves protective or deleterious has been thought to depend on its ability to recruit new units and whether DP or plateau pressure remains unchanged during the increase.…”

mentioning

confidence: 99%

“…Even though logically weighted, not all components of the proposed power equation contribute to VILI in an obvious way. For instance, although flow magnitude and flow profile (attack rate dP/dt) relate to the aggressiveness of lung tissue expansion during inflation and may contribute to damage for that reason [2,7], it is difficult to link power dissipated in proximal airway resistance directly to noxious events at the alveolar level.…”

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confidence: 99%

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Dynamic predictors of VILI risk: beyond the driving pressure

Marini

Jaber

2016

Intensive Care Med

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Strain, strain rate, and mechanical power: An optimization comparison for oscillatory ventilation

Herrmann

Tawhai

Kaczka

2019

Numer Methods Biomed Eng

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The purpose of this study was to assess the potential for optimization of mechanical ventilator waveforms using multiple frequencies of oscillatory flow delivered simultaneously to minimize the risk of ventilator‐induced lung injury (VILI) associated with regional strain, strain rate, and mechanical power. Optimization was performed using simulations of distributed oscillatory flow and gas transport in a computational model of anatomically derived branching airway segments and viscoelastic terminal acini under healthy and injured conditions. Objective functions defined by regional strain or strain rate were minimized by single‐frequency ventilation waveforms using the highest or lowest frequencies available, respectively. However, a mechanical power objective function was minimized by a combination of multiple frequencies delivered simultaneously. This simulation study thus demonstrates the potential for multifrequency oscillatory ventilation to reduce regional mechanical power in comparison to single‐frequency ventilation, and thereby reduce the risk of VILI.

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Role of Strain Rate in the Pathogenesis of Ventilator-Induced Lung Edema*

Abstract: High strain rate is a risk factor for ventilator-induced pulmonary edema, possibly because it amplifies lung viscoelastic behavior.

Cited by 117 publications

References 37 publications

Driving pressure and mechanical power: new targets for VILI prevention

Driving pressure and mechanical power: new targets for VILI prevention

Dynamic predictors of VILI risk: beyond the driving pressure

Strain, strain rate, and mechanical power: An optimization comparison for oscillatory ventilation

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