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Journal of veterinary internal medicine2021; 35(4); 2035-2044; doi: 10.1111/jvim.16152

Can bronchoconstriction and bronchodilatation in horses be detected using electrical impedance tomography?

Abstract: Electrical impedance tomography (EIT) generates images of the lungs based on impedance change and was able to detect changes in airflow after histamine challenge in horses. Objective: To confirm that EIT can detect histamine-provoked changes in airflow and subsequent drug-induced bronchodilatation. Novel EIT flow variables were developed and examined for changes in airflow. Methods: Bronchoconstriction was induced using stepwise histamine bronchoprovocation in 17 healthy sedated horses. The EIT variables were recorded at baseline, after saline nebulization (control), at the histamine concentration causing bronchoconstriction (Cmax ) and 2 and 10 minutes after albuterol (salbutamol) administration. Peak global inspiratory (PIFEIT ) and peak expiratory EIT (PEFEIT ) flow, slope of the global expiratory flow-volume curve (FVslope ), steepest FVslope over all pixels in the lung field, total impedance change (surrogate for tidal volume; VTEIT ) and intercept on the expiratory FV curve normalized to VTEIT (FVintercept /VTEIT ) were indexed to baseline and analyzed for a difference from the control, at Cmax , 2 and 10 minutes after albuterol. Multiple linear regression explored the explanation of the variance of Δflow, a validated variable to evaluate bronchoconstriction using all EIT variables. Results: At Cmax , PIFEIT , PEFEIT , and FVslope significantly increased whereas FVintercept /VT decreased. All variables returned to baseline 10 minutes after albuterol. The VTEIT did not change. Multivariable investigation suggested 51% of Δflow variance was explained by a combination of PIFEIT and PEFEIT . Conclusions: Changes in airflow during histamine challenge and subsequent albuterol administration could be detected by various EIT flow volume variables.
Publication Date: 2021-05-11 PubMed ID: 33977584PubMed Central: PMC8295671DOI: 10.1111/jvim.16152Google Scholar: Lookup
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  • Journal Article

Summary

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The research article explores if Electrical Impedance Tomography (EIT) can detect lung changes due to bronchoconstriction and bronchodilatation in horses after tests using histamine and drug treatments.

Research Objective

The goal of this study was to verify if EIT, a diagnostic technique that creates images based on changes in impedance (resistance to electrical current), could detect changes in airflow in horses’ lungs prompted by a histamine challenge and subsequent treatment with a bronchodilator.

Methodology

  • The researchers caused bronchoconstriction in 17 healthy, sedated horses by administering histamine in stages.
  • EIT variables were recorded before any treatment (baseline), after nebulization with saline as a control, at the histamine concentration that caused bronchoconstriction, and 2 and 10 minutes after Albuterol (a bronchodilator) administration.
  • The study introduced new EIT flow variables specifically designed to evaluate changes in airflow.
  • A multiple linear regression analysis was utilized to examine how EIT variables explained changes in airflow variability.

Findings

  • As bronchoconstriction took effect, some EIT variables such as peak inspiratory flow (PIF), peak expiratory EIT flow (PEF), and slope of the global expiratory flow-volume curve (FV) were found to increase markedly. Furthermore, FV normalized to Tidal Volume (VT), another EIT variable, was found to decrease.
  • All changes reverted to their baseline values ten minutes after Albuterol administration, suggesting successful bronchodilation.
  • Interestingly, the total impedance change (a surrogate measure for tidal volume) saw no changes.
  • Using multivariable analysis, the study found that a combination of PIF and PEF accounted for 51% of the variance in the change in airflow, underlining their potential as significant indicators of bronchoconstriction.

Conclusion

The research concluded that changes in airflow as a result of histamine-induced bronchoconstriction and subsequent Albuterol-induced bronchodilatation could indeed be observed using EIT through the application of specific variables. This underscores EIT’s potential as a non-invasive and valuable diagnostic tool for veterinary respiratory medicine.

Cite This Article

APA
Secombe C, Adler A, Hosgood G, Raisis A, Mosing M. (2021). Can bronchoconstriction and bronchodilatation in horses be detected using electrical impedance tomography? J Vet Intern Med, 35(4), 2035-2044. https://doi.org/10.1111/jvim.16152

Publication

ISSN: 1939-1676
NlmUniqueID: 8708660
Country: United States
Language: English
Volume: 35
Issue: 4
Pages: 2035-2044

Researcher Affiliations

Secombe, Cristy
  • School of Veterinary Medicine, Murdoch University, Perth, Australia.
Adler, Andy
  • Systems and Computer Engineering, Carleton University, Ottawa, Canada.
Hosgood, Giselle
  • School of Veterinary Medicine, Murdoch University, Perth, Australia.
Raisis, Anthea
  • School of Veterinary Medicine, Murdoch University, Perth, Australia.
Mosing, Martina
  • School of Veterinary Medicine, Murdoch University, Perth, Australia.

MeSH Terms

  • Animals
  • Bronchoconstriction
  • Electric Impedance
  • Horses
  • Lung
  • Tidal Volume
  • Tomography, X-Ray Computed

Conflict of Interest Statement

Andy Adler and Martina Mosing are developing a commercial product that uses technology developed in this paper. All other authors have declared that their contribution to the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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