Bedside estimation of recruitable alveolar collapse and hyperdistension by electrical impedance tomography

Costa, Eduardo L. V.; Borges, João Batista; Melo, Alexandre; Suárez-Sipmann, Fernando; Toufen, Carlos; Böhm, Stephan H.; Amato, Marcelo Britto Passos

doi:10.1007/s00134-009-1447-y

Cited by 381 publications

(386 citation statements)

References 25 publications

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“…98 Electrical impedance tomography has the potential for bedside use to estimate regional alveolar collapse and overdistention. [98][99][100][101][102][103] To date, experience with electrical impedance tomography in North America is limited.…”

Section: Imagingmentioning

confidence: 99%

Recruitment Maneuvers and PEEP Titration

2015

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The injurious effects of alveolar overdistention are well accepted, and there is little debate regarding the importance of pressure and volume limitation during mechanical ventilation. The role of recruitment maneuvers is more controversial. Alveolar recruitment is desirable if it can be achieved, but the potential for recruitment is variable among patients with ARDS. A stepwise recruitment maneuver, similar to an incremental PEEP titration, is favored over sustained inflation recruitment maneuvers. Many approaches to PEEP titration have been proposed, and the best method to choose the most appropriate level for an individual patient is unclear. A PEEP level should be selected that balances alveolar recruitment against overdistention. The easiest approach to select PEEP might be according to the severity of the disease: 5-10 cm H 2 O PEEP in mild ARDS, 10 -15 cm H 2 O PEEP in moderate ARDS, and 15-20 cm H 2 O PEEP in severe ARDS. Recruitment maneuvers and PEEP should be used within the context of lung protection and not just as a means of improving oxygenation.

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Section: Imagingmentioning

confidence: 99%

Recruitment Maneuvers and PEEP Titration

2015

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“…Therefore the knowledge of lung recruitability may impact the mechanical ventilation setting [11]. Different methods such as the pressure-volume curve of the respiratory system [5,6], the use of electrical impedance tomography [8,31], nitrogen washout/washin technique [32], and transthoracic lung ultrasound [9] have been proposed to estimate lung recruitability [4]. Although lung CT scan requires the transportation of patients and exposure to radiation, it remains the reference method for assessing lung recruitability [11].…”

Section: Discussionmentioning

confidence: 99%

“…However, it may underestimate lung recruitment in patients with focal aeration loss [7]. Electrical impedance tomography provides noninvasive real-time imaging of pulmonary inflation which could predict the lung recruitability [8], but it computes only a small fraction of the lung and is affected by the movements of intrathoracic blood due to the application of PEEP. Recently, Bouhemad et al [9] showed that PEEPinduced lung recruitment estimated by transthoracic lung ultrasound was related to the one computed by the pressure-volume curves.…”

Section: Introductionmentioning

confidence: 99%

Visual anatomical lung CT scan assessment of lung recruitability

et al. 2012

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Purpose: The computation of lung recruitability in acute respiratory distress syndrome (ARDS) is advocated to set positive end-expiratory pressure (PEEP) for preventing lung collapse. The quantitative lung CT scan, obtained by manual image processing, is the reference method but it is time consuming. The aim of this study was to evaluate the accuracy of a visual anatomical analysis compared with a quantitative lung CT scan analysis in assessing lung recruitability. Methods: Fifty sets of two complete lung CT scans of ALI/ARDS patients computing lung recruitment were analyzed. Lung recruitability computed at an airway pressure of 5 and 45 cmH 2 O was defined as the percentage decrease in the collapsed/ consolidated lung parenchyma assessed by two expert radiologists using a visual anatomical analysis and as the decrease in not aerated lung regions using a quantitative analysis computed by dedicated software.Results: Lung recruitability was 11.3 % (interquartile range 7.39-16.41) and 15.5 % (interquartile range 8.18-21.43) with the visual anatomical and quantitative analysis, respectively. In the Bland-Altman analysis, the bias and agreement bands between the visual anatomical and quantitative analysis were -2.9 % (-11.8 to ?5.9 %). The ROC curve showed that the optimal cutoff values for the visual anatomical analysis in predicting high versus low lung recruitability was 8.9 % (area under the ROC curve 0.9248, 95 % CI 0.8550-0.9946). Considering this cutoff, the sensitivity, specificity, and diagnostic accuracy were 0.96, 0.76, and 0.86, respectively. Conclusions: Visual anatomical analysis can classify patients into those with high and low lung recruitability allowing more intensivists to get access to lung recruitability assessment.

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“…Alimentos ou líquidos de condutividade conhecida podem ser usados como contraste [23] para medir não só a velocidade de esvaziamento gástrico como também a motilidade gástrica [24]. Outra aplicação comum da TIE é o monitoramento da função pulmonar [25][26][27][28], incluindo a geração de imagens de ventilação e perfusão pulmonares, a investigação de embolia pulmonar, derrames e efeitos da ventilação mecânica. Além dessas aplicações, podem-se citar ainda o monitoramento do sistema circulatório [28][29][30][31] e a detecção de câncer de mama [32].…”

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“…A detecção de algumas alterações pulmonares já é feita com o uso de TIE, como a detecção de pneumotórax [25] e colapso alveolar [26], mas são baseadas em imagens de diferenças da caixa torácica e, por isso, é necessário que a monitorização seja iniciada antes do aparecimento da alteração pulmonar. A obtenção de imagens absolutas tridimensionais do pulmão pode possibilitar a detecção e localização dessas alterações nos casos em que a condição já existia antes do início da monitoração com TIE.…”

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Desenvolvimento de algoritmo de imagens absolutas de tomografia por impedância elétrica para uso clínico.

Camargo¹

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Electrical Impedance Tomography is a non invasive imaging technique that can be used in clinical applications to infer living tissue impeditivity from boundary electrical measurements. Mathematically this is an non-linear ill-posed inverse problem. Usually a spatial high-pass Gaussian filter is used as a regularization method for solving the inverse problem. The main objective of this work is to propose the use of physiological and anatomical priors of tissue resistivity distribution within the thorax, also known as anatomical atlas, in conjunction with the Gaussian filter as regularization methods. The proposed methodology employs the finite element method and the Gauss-Newton algorithm in order to reconstruct three-dimensional resistivity images. The Approximation Error Theory is used to reduce discretization effects and mesh size errors. Electrical impedance tomography data and computed tomography images of physiological pulmonary changes collected in vivo in a swine were used to validate the proposed method. The images obtained are compatible with atelectasis, pneumothorax, pleural effusion and different ventilation pressures during mechanical ventilation. The results show that image reconstruction from swines with clinically significant information is feasible when both the Gaussian filter and the anatomical atlas are used as regularization methods.vi

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Bedside estimation of recruitable alveolar collapse and hyperdistension by electrical impedance tomography

Abstract: We described an EIT-based method for estimating recruitable alveolar collapse at the bedside, pointing out its regional distribution. Additionally, we proposed a measure of lung hyperdistension based on regional lung mechanics.

Cited by 381 publications

References 25 publications

Recruitment Maneuvers and PEEP Titration

Recruitment Maneuvers and PEEP Titration

Visual anatomical lung CT scan assessment of lung recruitability

Desenvolvimento de algoritmo de imagens absolutas de tomografia por impedância elétrica para uso clínico.

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