Determination of respiratory gas flow by electrical impedance tomography in an animal model of mechanical ventilation

Bodenstein, Marc; Boehme, Stefan; Bierschock, Stephan; Vogt, Andreas; David, Matthias; Markstaller, Klaus

doi:10.1186/1471-2466-14-73

Cited by 11 publications

(20 citation statements)

References 19 publications

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“…; Bodenstein et al. ). Exposure to LBNP exerted a less appreciable effect on regional lung ventilation than the acute changes in gravity, and specifically in response to LBNP, the regional tidal volumes in the ventral and dorsal regions did not significantly differ from each other.…”

Section: Discussionmentioning

confidence: 98%

Aging modifies the effect of cardiac output on middle cerebral artery blood flow velocity

et al. 2017

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An association between cerebral blood flow (CBF) and cardiac output (CO) has been established in young healthy subjects. As of yet it is unclear how this association evolves over the life span. To that purpose, we continuously recorded mean arterial pressure (MAP; finger plethysmography), CO (pulse contour; CO‐trek), mean blood flow velocity in the middle cerebral artery (MCAV; transcranial Doppler ultrasonography), and end‐tidal CO 2 partial pressure (PetCO 2) in healthy young (19–27 years), middle‐aged (51–61 years), and elderly subjects (70–79 years). Decreases and increases in CO were accomplished using lower body negative pressure and dynamic handgrip exercise, respectively. Aging in itself did not alter dynamic cerebral autoregulation or cerebrovascular CO 2 reactivity. A linear relation between changes in CO and MCAV mean was observed in middle‐aged (P < 0.01) and elderly (P = 0.04) subjects but not in young (P = 0.45) subjects, taking concurrent changes in MAP and PetCO 2 into account. These data imply that with aging, brain perfusion becomes increasingly dependent on CO.

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Section: Discussionmentioning

confidence: 98%

Aging modifies the effect of cardiac output on middle cerebral artery blood flow velocity

et al. 2017

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“…The total impedance change during inspiration and expiration corresponds with the inspired and expired volume . Peak inspiratory (InF global ) and peak expiratory (ExF global ) global flow can be evaluated by calculating the first derivative of the EIT volume signal . The clinical usefulness of EIT‐derived flow signals to diagnose global and regional ventilation characteristics related to changes in airway diameters has been shown recently in human subjects .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of histamine‐provoked changes in airflow using electrical impedance tomography in horses

Secombe

Waldmann

Hosgood

et al. 2020

Equine Veterinary Journal

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Background Electrical impedance tomography (EIT) generates thoracic impedance images of the lungs and has been used to assess ventilation in horses. This technique may have application in the detection of changes in airflow associated with equine asthma. Objectives The objective was to determine if histamine‐induced airflow changes observed with flowmetric plethysmography (Δflow) could also be explained using global and regional respiratory gas flow signals calculated from EIT signals. Study design Experimental in vivo study. Methods Six horses, sedated using detomidine were fitted with a thoracic EIT belt and flowmetric plethysmography hardware. Saline (baseline = BL) and increasing concentrations of histamine (C1‐4) were nebulised into the face mask until a change in breathing pattern was clinically confirmed and Δflow increased greater or equal to 50%. After nebulisation Δflow and EIT images were recorded over 3 minutes and peak global inspiratory (InFglobal) and expiratory (ExFglobal) flow as well as peak regional expiratory and inspiratory flow for the dorsal and the ventral area of the right and left lungs were evaluated. Delta flow, InFglobal and ExFglobal at subsequent concentrations were indexed to baseline (yi = Ci/BL−1). Indexed and nonindexed variables were evaluated for a difference from baseline at sequential histamine doses (time). Multiple linear regression assessment of variance in delta flow was also investigated. Results Consistent with histamine‐provoked increases in Δflow, the global flow indices increased significantly. A significant increase in regional inspiratory flow was seen in the right and left ventral lung and dorsal right lung. Multiple regression revealed that the variance in ExFglobal, and right and left ventral expiratory flow best explained the variance in Δflow (r2 = .82). Main limitations Low number of horses and horses were healthy. Conclusions Standardised changes in airflow during histamine challenge could be detected using EIT gas flow variables.

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“…In the present study, following preliminary data obtained in animal model [8], we aimed to validate in intubated AHRF and ARDS patients undergoing controlled ventilation and spontaneous breathing EIT-based measures of global MIF and MEF against standard spirometry. Moreover, we explored the effects of higher vs. lower PEEP and pressure support levels on regional flows; our hypothesis is that higher PEEP and lower pressure support could yield more homogenous distribution of regional MIF and MEF.…”

Section: Introductionmentioning

confidence: 99%

Noninvasive assessment of airflows by electrical impedance tomography in intubated hypoxemic patients: an exploratory study

Mauri

Spinelli

Corte

et al. 2019

Ann. Intensive Care

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Background Noninvasive monitoring of maximal inspiratory and expiratory flows (MIF and MEF, respectively) by electrical impedance tomography (EIT) might enable early recognition of changes in the mechanical properties of the respiratory system due to new conditions or in response to treatments. We aimed to validate EIT-based measures of MIF and MEF against spirometry in intubated hypoxemic patients during controlled ventilation and spontaneous breathing. Moreover, regional distribution of maximal airflows might interact with lung pathology and increase the risk of additional ventilation injury. Thus, we also aimed to describe the effects of mechanical ventilation settings on regional MIF and MEF. Methods We performed a new analysis of data from two prospective, randomized, crossover studies. We included intubated patients admitted to the intensive care unit with acute hypoxemic respiratory failure (AHRF) and acute respiratory distress syndrome (ARDS) undergoing pressure support ventilation (PSV, n = 10) and volume-controlled ventilation (VCV, n = 20). We measured MIF and MEF by spirometry and EIT during six different combinations of ventilation settings: higher vs. lower support during PSV and higher vs. lower positive end-expiratory pressure (PEEP) during both PSV and VCV. Regional airflows were assessed by EIT in dependent and non-dependent lung regions, too. Results MIF and MEF measured by EIT were tightly correlated with those measured by spirometry during all conditions (range of R 2 0.629–0.776 and R 2 0.606–0.772, respectively, p < 0.05 for all), with clinically acceptable limits of agreement. Higher PEEP significantly improved homogeneity in the regional distribution of MIF and MEF during volume-controlled ventilation, by increasing airflows in the dependent lung regions and lowering them in the non-dependent ones. Conclusions EIT provides accurate noninvasive monitoring of MIF and MEF. The present study also generates the hypothesis that EIT could guide PSV and PEEP settings aimed to increase homogeneity of distending and deflating regional airflows. Electronic supplementary material The online version of this article (10.1186/s13613-019-0560-5) contains supplementary material, which is available to authorized users.

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Determination of respiratory gas flow by electrical impedance tomography in an animal model of mechanical ventilation

Cited by 11 publications

References 19 publications

Aging modifies the effect of cardiac output on middle cerebral artery blood flow velocity

Aging modifies the effect of cardiac output on middle cerebral artery blood flow velocity

Evaluation of histamine‐provoked changes in airflow using electrical impedance tomography in horses

Noninvasive assessment of airflows by electrical impedance tomography in intubated hypoxemic patients: an exploratory study

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