Regional pressure volume curves by electrical impedance tomography in a model of acute lung injury

Kunst, Peter W.A.; Böhm, Stephan H.; Anda, Gilberto Felipe Vázquez de; Amato, Marcelo B. P.; Lachmann, Burkhard; Postmus, P.E.; Vries, P. M. J. M. De

doi:10.1097/00003246-200001000-00029

Cited by 100 publications

(88 citation statements)

References 14 publications

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“…The application of moderate levels of external PEEP (6 ¡ 2 cmH 2 O) abolished intrinsic PEEP and LIP, reduced time constants and increased compliance of the respiratory system, suggesting the homogenisation of alveolar ventilation. The P/V curve of the respiratory system reflects, therefore, different lung regions with heterogeneous mechanical properties and is a composite of multiple regional P/V curves [35].…”

Section: Interpretation Of the Pressure/volume Curve: A New Insightmentioning

confidence: 99%

What has been learnt from P/V curves in patients with acute lung injury/acute respiratory distress syndrome

Maggiore¹,

Richard²,

Brochard³

2003

European Respiratory Journal

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What has been learnt from P/V curves in patients with acute lung injury/acute respiratory distress syndrome. S.M. Maggiore, J-C. Richard, L. Brochard. #ERS Journals Ltd 2003. ABSTRACT: Mechanical impairment of the respiratory system was recognised soon after the description of acute respiratory distress syndrome. The analysis of the pressure/volume (P/V) curve of the respiratory system contributed a lot to the understanding of the pathophysiology of acute lung injury and formed the basis for lung protection. The lower and upper inflection points were regarded as points of interest to avoid cyclic derecruitment and overdistension and to optimise ventilatory settings. However, because of the heterogeneity of lung injury, reducing the mechanical properties of the whole respiratory system to a single curve is a schematic approach, which makes interpretation difficult.New data suggest that alveolar re-inflation occurs along the whole P/V curve that can, therefore, be considered as a recruitment curve. The lower inflection point has no relationship with alveolar opening and closure and does not indicate the positive endexpiratory pressure needed to prevent alveolar collapse. The shape of the P/V curve gives information about the extension and the homogeneity of lung injury, indicating the possibility of lung recruitment. The upper inflection point, classically seen as the beginning of overdistension, may also indicate the end of recruitment.The pressure/volume curve offers the unique opportunity of evaluating alveolar recruitment/derecruitment at the bedside that can be helpful for the identification of optimal ventilatory settings and makes the curve a valuable tool for the ventilatory management of acute lung injury. Eur Respir J 2003; 22: Suppl. 42, 22s-26s. Since its first description, acute respiratory distress syndrome (ARDS) was recognised as a condition characterised by the decrease of lung volume and mechanical abnormalities of the respiratory system [1]. It was therefore tempting to correlate the mechanical impairment of the respiratory system with the severity of the disease and to set the ventilatory parameters accordingly. In 1972, FALKE et al.[2] described the changes in dynamic compliance and tidal pressure/volume (P/V) loops with the application of positive end-expiratory pressure (PEEP) in patients with acute respiratory failure (currently classified as acute lung injury (ALI) or ARDS) [2]. A few years later, SUTER et al. [3] showed in a classical paper that the measurement of static or effective compliance (calculated by dividing the tidal volume (VT) by the difference between end-inspiratory plateau pressure and end-expiratory pressure) could be helpful in determining the PEEP level resulting in optimum cardiopulmonary function. The PEEP level corresponding to the highest static compliance resulted in the best oxygen transport and the lowest deadspace fraction, suggesting optimal alveolar recruitment without overdistension. However, the interaction between ventilatory settings and respiratory mechan...

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Section: Interpretation Of the Pressure/volume Curve: A New Insightmentioning

confidence: 99%

What has been learnt from P/V curves in patients with acute lung injury/acute respiratory distress syndrome

Maggiore¹,

Richard²,

Brochard³

2003

European Respiratory Journal

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“…This adjustment (Eq. (18) and Table 3) characterizes the condition of sickness, in our case the COPD, in a group of subjects. The most important parameters involved in the COPD adjustment equations were subscapular skinfold and height.…”

Section: Discussionmentioning

confidence: 99%

“…Different research groups have used the EIT technique in order to describe the behavior of respiratory pattern (RP) [12,13] and detect lung diseases. Some important pneumological applications by using EIT are: (1) the development of an artificial pneumothorax in a controlled experimental setting [14,15], (2) the quantification of the amount of fluid volume in lungs [16,17] and (3) the determination of regional pressure-volume curves [18][19][20]. However, the most important EIT application in pneumology area is the regional lung ventilation monitoring as a function of positive end-expiratory pressure (PEEP) in patients in use of mechanical ventilation [21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Tidal volume monitoring by electrical impedance tomography (EIT) using different regions of interest (ROI): Calibration equations

Balleza

Alday

Vargas-Luna

et al. 2015

Biomedical Signal Processing and Control

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a b s t r a c t A set of calibration equations was previously obtained to transform the lung impedance changes obtained by electrical impedance tomography (EIT), using all frame's elements, into a measurable volume signal. In order to study the goodness of the use of regions of interest (ROI) for lung ventilation monitoring, we considered 6 different ROI to obtain a calibration equation for each area. Our aim was to compare the results, determined by these areas, and those obtained by using all EIT image elements. Two ROI's were defined by those pixels with an impedance change higher than 30% and 70% of the maximum change value. These areas were called P30 and P70, respectively. Two other ROI were defined by bounding two areas by mouse, resembling P30 and P70 regions, which were called M30 and M70, respectively. The remainder was defined by two elliptical areas with an eccentricity of 0.8, and 25 and 32 pixels of mayor axis (E25p and E32p, respectively). Twenty healthy males and 24 chronic obstructive pulmonary disease (COPD) patients were considered. For small region (P30 and M30) we obtained a large dispersion in volume measurement, concluding that small regions are not suitable for monitoring the tidal changes in lung volume even for healthy subjects. The results obtained by the remainder areas, and by using EIT image were similar. Even a slight improvement in data dispersion was obtained by using some ROI. These optimal results, for healthy people, were those corresponding to P70 and M70 (volume dispersion improved from 12% with the whole EIT image to 9% using ROI), and for COPD patients improves volume dispersion from 32% using the whole EIT image to 27% by using E25p. Using not so small ROI, it is possible to estimate the total lung ventilation. IntroductionIn clinical environment, there is nothing good enough to measure and monitor in a non-invasive manner the breathing pattern (BP), especially during large periods of time. The BP monitoring provides information about neuromuscular alterations suffered by patients and assesses organs that regulate breathing [1,2]. The reference method aimed to monitor the BP is the pneumotachometer. However, this device spontaneously modifies the behavior of respiration between 15% and 35% due to the essential use of a mouthpiece and clip-nose [3][4][5][6]. The pneumotachometer is mainly used in exercise stress testing in order to assess the pulmonary functional capacity during exercise. Other alternative method to monitor BP is the respiratory inductance plethysmography (RIP). This equipment is used to estimate lung volume by detecting respiratory movements of chest and abdominal wall. This method has been almost completely abandoned due to calibration problems [7][8][9]. Nowadays, this technique is used to monitor qualitatively respiration in patients with obstructive sleep apnea/hypopnea syndrome. A new experimental method used in clinical environment is the electrical impedance tomography (EIT). EIT is used to image regional impedance distribution in a cross-sectional...

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“…A TIE avalia portanto alterações regionais pulmonares, sendo capaz de detectar áreas de colapso e hiperdistensão (58,60) . No entanto, a TIE tem como limitações ser uma técnica que fornece imagens e medidas relativas do pulmão além de assumir que a região avaliada pela cinta de eletrodos, colocada ao redor do tórax, é representativa de todo o pulmão.…”

Section: Ventilação Mecânica Protetora E Sdraunclassified

Titulação de PEEP por manobra rápida versus lenta utilizando tomografia de impedância elétrica, e estabilidade da função pulmonar com estratégia ventilatória protetora em modelo suíno de síndrome do desconforto respiratório agudo

Ortiz¹

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AgradecimentosAos meus pais pelo incentivo e apoio infinito. Vocês são um bálsamo em minha vida! Amo pra sempre! Ao meu marido Vando pela compreensão e apoio. Meu amor que me sustenta, me acompanha, me ensina, me acalma, me compreende... Te amo! Clarinha, minha riqueza! Obrigada por me ensinar a ser mais forte, mais confiante e segura. Você me faz crescer! Aos meus irmãos Rodrigo e Thiago pelo carinho, apoio e incentivo. Amo vocês! Às minhas queridas cunhadas Corina e Débora pelo carinho e amizade! Obrigada! Joana por ser minha segunda mãe! À família "Mão Unidas" pelo suporte e vibrações sempre! À minha querida família de Tangará: tia Nessa, tia Bibi, tia Vaninha, vovó Neiva, vovô Mundo, tia Dione, tio Humberto...todos que cuidaram da Clara, como se fosse uma filha! Minha eterna gratidão! Essa tese não teria saído sem o apoio de vocês.À tia Fátima e tia Ana: obrigada por cuidarem da minha família.Ao Fabinho e Rose, meus queridos irmãos que me abraçaram em Tangará da Serra.À Tatá (Thaís) pela compreensão e apoio. À Keyti, por "segurar a barra" sempre e nunca perder o bom humor.À querida Rafa, pela ajuda e cuidado em preparar as traduções.Aos professores e alunos da UNIC pelas palavras de incentivo.À toda equipe do LIM pelo apoio em todas as etapas:Neidoca por toda ajuda e carinho.Otília e Silvinha pela dedicação e apoio.Susi pela competência, pelos conselhos, por ser a minha "mãezona", me pegar pela mão e ensinar TUDO! Robertinha pela delicadeza, disciplina, generosidade e carinho. Você é um exemplo de perseverança e otimismo.Ozires, por todas as risadas! Por todas as conversas! Pelo seu exemplo de mãe, esposa e amiga.Andrea, por todas as risadas! Sempre com as piadas para descontrair.Miyuki, pelo exemplo de disciplina, organização, inteligência, competência e extrema habilidade em escrever, elaborar relatórios, e me ajudar desde o início.Elena pela doçura e meiguice. Sinto falta de você! À Marcinha por me ajudar desde o mestrado, com as correções, sugestões e atenção.Ao Germano por me inspirar a seguir na área acadêmica.Ao eterno "Maurão", que me fez descobrir o verdadeiro significado da palavra "altruísmo".Ao Marcelinho, Rollin, Takeshi, Caio, Glasi, Chris e Renato pelo apoio.Ao Edu pelo apoio e inteligência. Vini por trazer a ideia do estudo e sempre me auxiliar nas analises com esse seu jeito despachado e sempre muito atencioso Ao Dr. Carlos pelas aulas e acompanhamento no PAE. Genorosidade e humildade em pessoa.À professora Cida Basili, pelas maravilhosas aulas de didática na pós.Ao Dr. Marcelo. Cinco minutos preciosos com você me faziam acreditar que eu iria dar conta.Obrigada.Como diz a Clara: um "abaço foiti" em cada um de vocês! Muito obrigada. Introdução: A estratégia protetora de ventilação mecânica para a Síndrome do Desconforto Respiratório Agudo (SDRA), que associa o uso de baixo volume corrente com PEEP mais elevada, é uma intervenção eficaz para reduzir a morbimortalidade desta síndrome. Existe um consenso sobre o ajuste do volume corrente, mas o método de escolher a PEEP ainda é controverso. Dos ...

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Regional pressure volume curves by electrical impedance tomography in a model of acute lung injury

Abstract: Using EIT, determination of LIP and UDP from the regional PI curves is possible. The obtained information from the regional PI curves may help in understanding alveolar recruitment. The use of this new bedside technique for clinical decision making remains to be examined.

Cited by 100 publications

References 14 publications

What has been learnt from P/V curves in patients with acute lung injury/acute respiratory distress syndrome

What has been learnt from P/V curves in patients with acute lung injury/acute respiratory distress syndrome

Tidal volume monitoring by electrical impedance tomography (EIT) using different regions of interest (ROI): Calibration equations

Titulação de PEEP por manobra rápida versus lenta utilizando tomografia de impedância elétrica, e estabilidade da função pulmonar com estratégia ventilatória protetora em modelo suíno de síndrome do desconforto respiratório agudo

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