Assessment of regional lung recruitment and derecruitment during a PEEP trial based on electrical impedance tomography

Meier, T.; Luepschen, Henning; Karsten, Jan; Leibecke, Thorsten; Großherr, M.; Gehring, Hartmut; Leonhardt, Steffen

doi:10.1007/s00134-007-0786-9

Cited by 199 publications

(135 citation statements)

References 30 publications

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“…Our findings are in line with the study of VAN GENDERINGEN et al [24], showing a similar relationship between FRC and ventilation, expressed as the oscillatory pressure ratio, in highfrequency ventilated surfactant-deficient pigs. The fact that the association between FRC and (tidal) ventilation was also found in animal experiments using pressure-controlled ventilation indicates that these physiological principles are independent of the ventilation mode [15,18]. In an in vitro study, PILLOW et al…”

Section: Discussionmentioning

confidence: 88%

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The effect of airway pressure and oscillation amplitude on ventilation in pre-term infants

Miedema

Jongh

Frerichs³

et al. 2012

Eur Respir J

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We determined the effect of lung recruitment and oscillation amplitude on regional oscillation volume and functional residual capacity (FRC) in high-frequency oscillatory ventilation (HFOV) used in pre-term infants with respiratory distress syndrome (RDS).Changes in lung volume, oscillation volume and carbon dioxide levels were recorded in 10 infants during a stepwise recruitment procedure, and an increase in pressure amplitude of 5 cmH 2 O was measured using electrical impedance tomography and transcutaneous monitoring. The pressures at maximal respiratory system compliance, maximal oscillation volume and minimal carbon dioxide levels were determined. Impedance data were analysed for the chest cross-section and predefined regions of interest.Despite the fixed pressure amplitude, the oscillation volume changed during the incremental pressure steps following a parabolic pattern, with an inverse relationship to the carbon dioxide pressures. The pressures corresponding with maximal compliance, maximal oscillation volume and minimal carbon dioxide were similar and highly correlated. Regional analysis showed similar findings. The increase in pressure amplitude resulted in increased oscillation volumes and decreased carbon dioxide levels, while FRC remained unchanged.In HFV pre-term infants with RDS, oscillation volumes are closely related to the position of ventilation in the pressure-volume envelope and the applied pressure amplitude. Changes in pressure amplitude do not seem to affect FRC.

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Section: Discussionmentioning

confidence: 88%

“…EIT and noninvasively monitor changes in lung impedance, which are highly correlated with changes in gas volume [16]. EIT provides regional information on lung volume changes in the chest crosssection, which may be important in case of heterogeneous lung disease or gravitational effects [16][17][18][19].…”

mentioning

confidence: 99%

The effect of airway pressure and oscillation amplitude on ventilation in pre-term infants

Miedema

Jongh

Frerichs³

et al. 2012

Eur Respir J

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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%

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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“…The mouse and percentage methods are compared because in many situations a handmade determination of a clinical ROI is necessary to be performed in situ in order to obtain a better diagnostics. For example, the ventilatory pattern monitoring in those EIT areas produced by the alveolar recruitment in patients in use of mechanical ventilation [37]. Finally, the third method (ellipse method) consists on selecting those pixels determined by two elliptical masks placed in the SD EIT frame.…”

Section: Determination Of Roi'smentioning

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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Assessment of regional lung recruitment and derecruitment during a PEEP trial based on electrical impedance tomography

Abstract: EIT is suitable for monitoring the dynamic effects of PEEP variations on the regional change of tidal volume. It is superior to global ventilation parameters in assessing the beginning of alveolar recruitment and lung collapse.

Cited by 199 publications

References 30 publications

The effect of airway pressure and oscillation amplitude on ventilation in pre-term infants

The effect of airway pressure and oscillation amplitude on ventilation in pre-term infants

Visual anatomical lung CT scan assessment of lung recruitability

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

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