Assessment of distribution of ventilation by electrical impedance tomography in standing horses

Ambriskó, Tamás Dezső; Schramel, Johannes P.; Adler, Andy; Kutasi, O; Makra, Zita; Moens, Yves

doi:10.1088/0967-3334/37/2/175

Cited by 30 publications

(52 citation statements)

References 38 publications

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“…Some variability in tidal volumes and respiratory frequency was expected during eupnoea, as horses have significant respiratory reserve, and ventilation is subject to rapid change in response to excitement, fear and other emotional states. Additionally, horses regularly take single large breaths (sighs), which serve to redistribute ventilation within pulmonary fields [37]. Carbon dioxide-induced hyperpnoea attenuated both the within day and between day variability observed in the current study.…”

Section: Discussionmentioning

confidence: 76%

“…Time invested acclimatising horses to the test environment and spirometry procedures likely improved the reliability of the findings of the current study, and research methodology based on selection of three consecutive breaths, representative of the available spirometry trace and based on carefully defined inclusion criteria, was also designed to optimise repeatability and precision of PFT procedures. Previous respiratory studies have utilised analysis of three breaths from each epoch [18, 37], however, analysis of a greater number of breaths might increase the accuracy of derived measures of respiratory function [23], and further analyses may be indicated to determine the optimal number of breaths for analysis. Coefficients of variation in the current study were similar to, or less than, analogous results from previous studies [11, 34], and within acceptable limits for PFT [12].…”

Section: Discussionmentioning

confidence: 99%

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Reliability of breath by breath spirometry and relative flow-time indices for pulmonary function testing in horses

et al. 2016

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BackgroundRespiratory problems are common in horses, and are often diagnosed as a cause of poor athletic performance. Reliable, accurate and sensitive spirometric tests of airway function in resting horses would assist with the diagnosis of limitations to breathing and facilitate investigations of the effects of various treatments on breathing capacity. The evaluation of respiratory function in horses is challenging and suitable procedures are not widely available to equine practitioners. The determination of relative flow or flow-time measures is used in paediatric patients where compliance may limit conventional pulmonary function techniques. The aim of the current study was to characterise absolute and relative indices of respiratory function in healthy horses during eupnoea (tidal breathing) and carbon dioxide (CO2)-induced hyperpnoea (rebreathing) using a modified mask pneumotrachographic technique well suited to equine practice, and to evaluate the reliability of this technique over three consecutive days. Coefficients of variation, intra-class correlations, mean differences and 95% confidence intervals across all days of testing were established for each parameter.ResultsThe technique provided absolute measures of respiratory function (respiratory rate, tidal volume, peak inspiratory and expiratory flows, time to peak flow) consistent with previous studies and there was no significant effect of day on any measure of respiratory function. Variability of measurements was decreased during hyperpnea caused by rebreathing CO2, but a number of relative flow-time variables demonstrated good agreement during eupnoeic respiration.ConclusionsThe technique was well tolerated by horses and study findings suggest the technique is suitable for evaluation of respiratory function in horses. The use of relative flow-time variables provided reproducible (consistent) results, suggesting the technique may be of use for repeated measures studies in horses during tidal breathing or rebreathing.Electronic supplementary materialThe online version of this article (doi:10.1186/s12917-016-0893-3) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

Reliability of breath by breath spirometry and relative flow-time indices for pulmonary function testing in horses

et al. 2016

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“…The existence of inverse respiratory signals is known [ 22 ] and a previous horse study from our institution demonstrated that the location of such signals was predictable and corresponded to the location of abdominal gas pockets [ 23 ]. Nevertheless, in the current study, the inverse signals were unremarkable and did not seem to correspond to any particular anatomical structure.…”

Section: Discussionmentioning

confidence: 99%

Impact of four different recumbencies on the distribution of ventilation in conscious or anaesthetized spontaneously breathing beagle dogs: An electrical impedance tomography study

et al. 2017

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The aim was to examine the effects of recumbency and anaesthesia on distribution of ventilation in beagle dogs using Electrical Impedance Tomography (EIT). Nine healthy beagle dogs, aging 3.7±1.7 (mean±SD) years and weighing 16.3±1.6 kg, received a series of treatments in a fixed order on a single occasion. Conscious dogs were positioned in right lateral recumbency (RLR) and equipped with 32 EIT electrodes around the thorax. Following five minutes of equilibration, two minutes of EIT recordings were made in each recumbency in the following order: RLR, dorsal (DR), left (LLR) and sternal (SR). The dogs were then positioned in RLR, premedicated (medetomidine 0.01, midazolam 0.1, butorphanol 0.1 mg kg-1 iv) and pre-oxygenated. Fifteen minutes later anaesthesia was induced with 1 mg kg-1 propofol iv and maintained with propofol infusion (0.1–0.2 mg kg-1 minute-1 iv). After induction, the animals were intubated and allowed to breathe spontaneously (FIO2 = 1). Recordings of EIT were performed again in four recumbencies similarly to conscious state. Centre of ventilation (COV) and global inhomogeneity (GI) index were calculated from the functional EIT images. Repeated-measures ANOVA and Bonferroni tests were used for statistical analysis (p < 0.05). None of the variables changed in the conscious state. During anaesthesia left-to-right COV increased from 46.8±2.8% in DR to 49.8±2.9% in SR indicating a right shift, and ventral-to-dorsal COV increased from 49.8±1.7% in DR to 51.8±1.1% in LLR indicating a dorsal shift in distribution of ventilation. Recumbency affected distribution of ventilation in anaesthetized but not in conscious dogs. This can be related to loss of respiratory muscle tone (e.g. diaphragm) and changes in thoracic shape. Changing position of thoraco-abdominal organs under the EIT belt should be considered as alternative explanation of these findings.

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“…Based on the conductivity changes of contrasting air and blood flow in lungs, the bio-electrical properties of pulmonary tissue can be imaged by EIT. In addition, EIT can be used for continuously bedside monitoring the condition of patients suffering from acute respiratory distress syndrome (ARDS) in intensive care units (ICU) [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Optimal distance of multi-plane sensor in three-dimensional electrical impedance tomography

Hao

Yue

Sun

et al. 2017

Computer Assisted Surgery

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Electrical impedance tomography (EIT) is a visual imaging technique for obtaining the conductivity and permittivity distributions in the domain of interest. As an advanced technique, EIT has the potential to be a valuable tool for continuously bedside monitoring of pulmonary function. The EIT applications in any three-dimensional (3 D) field are very limited to the 3 D effects, i.e. the distribution of electric field spreads far beyond the electrode plane. The 3 D effects can result in measurement errors and image distortion. An important way to overcome the 3 D effect is to use the multiple groups of sensors. The aim of this paper is to find the best space resolution of EIT image over various electrode planes and select an optimal plane spacing in a 3 D EIT sensor, and provide guidance for 3 D EIT electrodes placement in monitoring lung function. In simulation and experiment, several typical conductivity distribution models, such as one rod (central, midway and edge), two rods and three rods, are set at different plane spacings between the two electrode planes. A Tikhonov regularization algorithm is utilized for reconstructing the images; the relative error and the correlation coefficient are utilized for evaluating the image quality. Based on numerical simulation and experimental results, the image performance at different spacing conditions is evaluated. The results demonstrate that there exists an optimal plane spacing between the two electrode planes for 3 D EIT sensor. And then the selection of the optimal plane spacing between the electrode planes is suggested for the electrodes placement of multi-plane EIT sensor.

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Assessment of distribution of ventilation by electrical impedance tomography in standing horses

Cited by 30 publications

References 38 publications

Reliability of breath by breath spirometry and relative flow-time indices for pulmonary function testing in horses

Reliability of breath by breath spirometry and relative flow-time indices for pulmonary function testing in horses

Impact of four different recumbencies on the distribution of ventilation in conscious or anaesthetized spontaneously breathing beagle dogs: An electrical impedance tomography study

Optimal distance of multi-plane sensor in three-dimensional electrical impedance tomography

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