Tidal recruitment assessed by electrical impedance tomography and computed tomography in a porcine model of lung injury*

Muders, Thomas; Luepschen, Henning; Zinserling, Jörg; Greschus, Susanne; Fimmers, Rolf; Guenther, Ulf; Buchwald, Miriam; Grigutsch, Daniel; Leonhardt, Steffen; Putensen, Christian; Wrigge, Hermann

doi:10.1097/ccm.0b013e318236f452

Cited by 132 publications

(174 citation statements)

References 48 publications

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“…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]. The effects of regional lung ventilation were studied in patients with acute lung injury (ALI) [24] or in animals [25][26][27][28]. Many research groups are studying the relation between the levels of PEEP and the impedance determinations obtained by EIT in order to find out the optimal PEEP.…”

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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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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“…RVD has been shown to give accurate data during 12-mL/kg slow insufflation manoeuver by Wrigge [123], later confirmed by Muders [125]. In our case, the data were from spontaneously breathing patients, therefore we cannot know with certainty that the RVD index relates to cyclic opening and closing of the alveoli.…”

Section: Limitations Of the Studymentioning

confidence: 55%

“…In recent times, a broader range of data has been able to be extracted and analysed using EIT. Variables such as RVD, VSA, CoV, and rNoVent are enabling an improved understanding of lung recruitment [56,122,125]. Ethics approval (HREC/13/QPCH/95) from local ethics committee was gained, an altered methodology similar to the research protocol described in Chapters 3 and 4 was utilised.…”

Section: Methodsmentioning

confidence: 99%

“…Novel methods of estimating lung recruitment using EIT have recently been described in the literature [125,126]. Two of these emerging EIT analyses to estimate changes in ventilation distribution and lung recruitment are VSA and RVD.…”

Section: Introductionmentioning

confidence: 99%

“…It gives data on delayed opening of lung areas that have been previously unopened or collapsed. Thus, alveolar recruitment can be detected by EIT and expressed as a simple index [123,125]: the smaller the index, the smaller the delay. VSA and RVD calculations in this study slightly differ from these of Blankman [126] as results are presented in pixel values, rather than percentage.…”

Section: Introductionmentioning

confidence: 99%

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Towards an improved understanding of the effect of a speaking valve on lung volumes and communication in the critically ill tracheostomised patient

Sutt¹

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Tracheostomised mechanically ventilated patients are often left unable to speak, which is frustrating for patients and the staff caring for them. Having no voice causes major distress and feelings of helplessness for patients. Voicelessness frequently leads to reduced information exchange between the patient and healthcare team, frequently to the detriment of patient care. An in-line speaking valve (SV) is a one-way valve that may be used in the mechanical ventilation circuit to enable verbal communication in tracheostomised patients.Limited data exist regarding the effect of SVs on respiratory mechanics. Deflation of the tracheostomy cuff is required for placement of the SV, effectively causing a "leak" in the As an experienced speech pathologist, I believe concerns over SV use to date have little evidence. The main objective, and first aim of this thesis was to investigate the effect of SV use on respiratory mechanics to determine whether SVs should be used in-line with mechanical ventilation of tracheostomised patients. The second aim was to assess the effect of introducing SVs into a cardio-thoracic ICU on patient tracheostomy specific outcomes. The third aim was to further clarify the effect of SVs on success with healthrelated communication for ICU patients. To achieve these aims, 5 studies were conducted, resulting in 5 manuscripts.For the first aim, 20 tracheostomised ICU patients using a SV that met the inclusion criteria were recruited to the study from November 2013-December 2014. Electrical Impedance iii Tomography (EIT) was used to assess the patients' end-expiratory lung impedance (EELI) and ventilation distribution continuously over 60 minutes (before, during and after SV use). For the third aim, 25 patients and 52 nursing staff were asked to fill out a custom-made questionnaire on success with health communication, firstly when the patients were voiceless, and, secondly, when they were using a SV. Chapter 7 highlights individual differences and some disparity between patient and nursing ratings of communication success. Overall, however, following SV use both the patients and nursing staff reported a significant improvement in success with health communication. Additional variables included oxygenation (SpOIn conclusion, the findings of this thesis addressed the research aims, and provide new knowledge through use of an innovative approach to assessing lung mechanics. Having iv already resulted in real clinical changes in our centre, the results indicate the potential for optimising communication, using SVs in tracheostomised cardiothoracic ICU patients undergoing weaning from mechanical ventilation.v

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Basics of Electrical Impedance Tomography and Its Application

Putensen

Hentze

Muders

2021

Cardiopulmonary Monitoring

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Tidal recruitment assessed by electrical impedance tomography and computed tomography in a porcine model of lung injury*

Cited by 132 publications

References 48 publications

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

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

Towards an improved understanding of the effect of a speaking valve on lung volumes and communication in the critically ill tracheostomised patient

Basics of Electrical Impedance Tomography and Its Application

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