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Byrne DP, Keeshan B, Hosgood G, Adler A, Mosing M. Comparison of electrical impedance tomography and spirometry-based measures of airflow in healthy adult horses. Front Physiol 2023; 14:1164646. [PMID: 37476683 PMCID: PMC10354512 DOI: 10.3389/fphys.2023.1164646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/26/2023] [Indexed: 07/22/2023] Open
Abstract
Electrical impedance tomography (EIT) is a non-invasive diagnostic tool for evaluating lung function. The objective of this study was to compare respiratory flow variables calculated from thoracic EIT measurements with corresponding spirometry variables. Ten healthy research horses were sedated and instrumented with spirometry via facemask and a single-plane EIT electrode belt around the thorax. Horses were exposed to sequentially increasing volumes of apparatus dead space between 1,000 and 8,500 mL, in 5-7 steps, to induce carbon dioxide rebreathing, until clinical hyperpnea or a tidal volume of 150% baseline was reached. A 2-min stabilization period followed by 2 minutes of data collection occurred at each timepoint. Peak inspiratory and expiratory flow, inspiratory and expiratory time, and expiratory nadir flow, defined as the lowest expiratory flow between the deceleration of flow of the first passive phase of expiration and the acceleration of flow of the second active phase of expiration were evaluated with EIT and spirometry. Breathing pattern was assessed based on the total impedance curve. Bland-Altman analysis was used to evaluate the agreement where perfect agreement was indicated by a ratio of EIT:spirometry of 1.0. The mean ratio (bias; expressed as a percentage difference from perfect agreement) and the 95% confidence interval of the bias are reported. There was good agreement between EIT-derived and spirometry-derived peak inspiratory [-15% (-46-32)] and expiratory [10% (-32-20)] flows and inspiratory [-6% (-25-18)] and expiratory [5% (-9-20)] times. Agreement for nadir flows was poor [-22% (-87-369)]. Sedated horses intermittently exhibited Cheyne-Stokes variant respiration, and a breath pattern with incomplete expiration in between breaths (crown-like breaths). Electrical impedance tomography can quantify airflow changes over increasing tidal volumes and changing breathing pattern when compared with spirometry in standing sedated horses.
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Affiliation(s)
- David P. Byrne
- School of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Ben Keeshan
- Department of Systems and Computer Engineering, Carleton University, Ottawa, ON, Canada
| | - Giselle Hosgood
- School of Veterinary Medicine, Murdoch University, Perth, WA, Australia
| | - Andy Adler
- Department of Systems and Computer Engineering, Carleton University, Ottawa, ON, Canada
| | - Martina Mosing
- Anaesthesiology and Perioperative Intensive Care, Department for Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria
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Secombe C, Adler A, Hosgood G, Raisis A, Mosing M. Can bronchoconstriction and bronchodilatation in horses be detected using electrical impedance tomography? J Vet Intern Med 2021; 35:2035-2044. [PMID: 33977584 PMCID: PMC8295671 DOI: 10.1111/jvim.16152] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND 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. OBJECTIVES 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 AND CLINICAL IMPORTANCE Changes in airflow during histamine challenge and subsequent albuterol administration could be detected by various EIT flow volume variables.
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Affiliation(s)
- Cristy Secombe
- School of Veterinary Medicine, Murdoch UniversityPerthAustralia
| | - Andy Adler
- Systems and Computer Engineering, Carleton UniversityOttawaCanada
| | - Giselle Hosgood
- School of Veterinary Medicine, Murdoch UniversityPerthAustralia
| | - Anthea Raisis
- School of Veterinary Medicine, Murdoch UniversityPerthAustralia
| | - Martina Mosing
- School of Veterinary Medicine, Murdoch UniversityPerthAustralia
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Dixon CE, Bedenice D, Mazan MR. Comparison of Flowmetric Plethysmography and Forced Oscillatory Mechanics to Measure Airway Hyperresponsiveness in Horses. Front Vet Sci 2021; 7:511023. [PMID: 33693040 PMCID: PMC7937713 DOI: 10.3389/fvets.2020.511023] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 09/18/2020] [Indexed: 11/13/2022] Open
Abstract
Airway hyperresponsiveness (AHR) is linked to airway inflammation and is considered a key manifestation of mild/moderate equine asthma (EA). The study purpose was to determine whether two modalities of non-invasive lung function testing (FOM-forced oscillatory mechanics vs. FP-flowmetric plethysmography) establish the same clinical diagnosis of AHR in horses, using histamine bronchoprovocation. Nineteen horses (3-25 years, 335-650 kg) with clinical signs suggestive of mild/moderate equine asthma were enrolled. FOM and FP testing was performed in each horse on two consecutive days, using a randomized cross-over design. AHR was defined by the histamine dose needed to double FOM baseline resistance, or to achieve a 35% increase in FP delta flow. Bronchoalveolar lavage fluid (BALF) was subsequently collected and stained with modified Wright's and toluidine blue stains. Binary statistical tests (related samples T-test, Mann-Whitney U, Chi-square analyses) were performed to compare study groups, with P < 0.05 considered significant. Abnormal BALF cytology confirmed EA in 14/19 (73.7%) horses. Both FOM and FP revealed AHR in 7/14 (50%) of these EA horses. An additional 4/19 (21.1%) horses showed AHR based on FP but not FOM, including two horses with normal BALF cytology. A diagnosis of AHR was more often associated with FP than FOM (P = 0.013), although the prevalence of AHR was significantly higher in EA vs. non-EA horses, regardless of testing methodology. The phase angle between thoracic and abdominal components of breathing did not differ between test groups. In conclusion, FP diagnosed AHR more frequently than did FOM, including horses with no other diagnostic evidence of EA. Without further evaluation, these two testing modalities of AHR cannot be used interchangeably.
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Affiliation(s)
- Claire E Dixon
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, United States
| | - Daniela Bedenice
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, United States
| | - Melissa R Mazan
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, United States
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Couetil L, Cardwell JM, Leguillette R, Mazan M, Richard E, Bienzle D, Bullone M, Gerber V, Ivester K, Lavoie JP, Martin J, Moran G, Niedźwiedź A, Pusterla N, Swiderski C. Equine Asthma: Current Understanding and Future Directions. Front Vet Sci 2020; 7:450. [PMID: 32903600 PMCID: PMC7438831 DOI: 10.3389/fvets.2020.00450] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 06/19/2020] [Indexed: 12/12/2022] Open
Abstract
The 2019 Havemeyer Workshop brought together researchers and clinicians to discuss the latest information on Equine Asthma and provide future research directions. Current clinical and molecular asthma phenotypes and endotypes in humans were discussed and compared to asthma phenotypes in horses. The role of infectious and non-infectious causes of equine asthma, genetic factors and proposed disease pathophysiology were reviewed. Diagnostic limitations were evident by the limited number of tests and biomarkers available to field practitioners. The participants emphasized the need for more accessible, standardized diagnostics that would help identify specific phenotypes and endotypes in order to create more targeted treatments or management strategies. One important outcome of the workshop was the creation of the Equine Asthma Group that will facilitate communication between veterinary practice and research communities through published and easily accessible guidelines and foster research collaboration.
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Affiliation(s)
- Laurent Couetil
- College of Veterinary Medicine, Purdue University, West Lafayette, IN, United States
| | - Jacqueline M Cardwell
- Department of Pathobiology and Population Sciences, Royal Veterinary College, London, United Kingdom
| | - Renaud Leguillette
- College of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
| | - Melissa Mazan
- Cummings School of Veterinary Medicine, Tufts University, Grafton, MA, United States
| | - Eric Richard
- LABÉO (Frank Duncombe), Normandie Université, UniCaen, Caen, France
| | - Dorothee Bienzle
- Department of Pathobiology, University of Guelph, Guelph, ON, Canada
| | - Michela Bullone
- Department of Veterinary Sciences, University of Turin, Grugliasco, Italy
| | - Vinzenz Gerber
- Vetsuisse Faculty, Institut Suisse de Médecine Équine (ISME), University of Bern and Agroscope, Bern, Switzerland
| | - Kathleen Ivester
- College of Veterinary Medicine, Purdue University, West Lafayette, IN, United States
| | - Jean-Pierre Lavoie
- Faculty of Veterinary Medicine, University of Montreal, Montreal, QC, Canada
| | - James Martin
- Meakins Christie Laboratories, McGill University Health Center Research Institute, Montreal, QC, Canada
| | - Gabriel Moran
- Department of Pharmacology, Faculty of Veterinary Sciences, Universidad Austral de Chile, Valdivia, Chile
| | - Artur Niedźwiedź
- Department of Internal Diseases With Clinic for Horses, Dogs and Cats, Wroclaw University of Environmental and Life Sciences, Wrocław, Poland
| | - Nicola Pusterla
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States
| | - Cyprianna Swiderski
- College of Veterinary Medicine, Mississippi State University, Starkville, MS, United States
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Burnheim K, Hughes KJ, Evans DL, Raidal SL. Reliability of breath by breath spirometry and relative flow-time indices for pulmonary function testing in horses. BMC Vet Res 2016; 12:268. [PMID: 27894292 PMCID: PMC5126818 DOI: 10.1186/s12917-016-0893-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 11/21/2016] [Indexed: 11/23/2022] Open
Abstract
Background Respiratory 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. Results The 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. Conclusions The 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 material The 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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Affiliation(s)
- K Burnheim
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, 2650, NSW, Australia
| | - K J Hughes
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, 2650, NSW, Australia
| | - D L Evans
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, 2650, NSW, Australia
| | - S L Raidal
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, 2650, NSW, Australia.
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Pacheco AP, Paradis MR, Hoffman AM, Hermida P, Sanchez A, Nadeau JA, Tufts M, Mazan MR. Age effects on blood gas, spirometry, airway reactivity, and bronchoalveolar lavage fluid cytology in clinically healthy horses. J Vet Intern Med 2014; 28:603-8. [PMID: 24528225 PMCID: PMC4857999 DOI: 10.1111/jvim.12318] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 11/16/2013] [Accepted: 01/06/2014] [Indexed: 11/10/2022] Open
Abstract
Background Despite the increasing number of geriatric horses attended by veterinarians, there is a lack of understanding of aging‐related changes on the respiratory system of horses. Objective To identify aging‐related changes on the respiratory function and bronchoalveolar lavage fluid (BALF) cytology of horses. Animals Fifteen healthy young adult (2–11 years) and 16 healthy aged (≥20 years) horses. Methods The respiratory system was examined by measurement of arterial blood gases (ABG), use of respiratory inductive plethysmography (RIP) for assessment of breathing pattern and ventilatory parameters, histamine bronchoprovocation, and BALF cytology. Results No significant differences were detected with regard to values obtained by ABG or bronchoprovocation of young adult and aged healthy horses. In aged horses, there were significant differences in mean ± SD of the following parameters when compared to young horses: prolonged expiratory time (Te) measured by RIP (3.9 ± 1.5 s versus 3.0 ± 0.6 s), decreased percentage of alveolar macrophages (40.6 ± 11.3% versus 53.5 ± 9.6%), and increased percentage of lymphocytes (53.4 ± 9.5% versus 43.9 ± 11.0%). No correlations between airway reactivity and ventilatory parameters, ABG, or BALF cytology were found in this asymptomatic population. Conclusions These results suggest that aging does not cause changes in the results obtained by ABG, most RIP‐derived variables, and bronchoprovocation in the horse. A decreased percentage of macrophage and an increased percentage of lymphocytes in the BALF cytology may be expected in the asymptomatic geriatric horse and may be a result of aging.
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Affiliation(s)
- A P Pacheco
- Department of Clinical Sciences, Cummings School of Veterinary Medicine, Tufts University, North Grafton, MA
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DeVanna JC, Kornegay JN, Bogan DJ, Bogan JR, Dow JL, Hawkins EC. Respiratory dysfunction in unsedated dogs with golden retriever muscular dystrophy. Neuromuscul Disord 2013; 24:63-73. [PMID: 24295812 DOI: 10.1016/j.nmd.2013.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 10/14/2013] [Accepted: 10/16/2013] [Indexed: 12/30/2022]
Abstract
Golden retriever muscular dystrophy (GRMD) is a well-established model of Duchenne muscular dystrophy. The value of this model would be greatly enhanced with practical tools to monitor progression of respiratory dysfunction during treatment trials. Arterial blood gas analysis, tidal breathing spirometry, and respiratory inductance plethysmography (RIP) were performed to determine if quantifiable abnormalities could be identified in unsedated, untrained, GRMD dogs. Results from 11 dogs with a mild phenotype of GRMD and 11 age-matched carriers were compared. Arterial blood gas analysis was successfully performed in all dogs, spirometry in 21 of 22 (95%) dogs, and RIP in 18 of 20 (90%) dogs. Partial pressure of carbon dioxide and bicarbonate concentration were higher in GRMD dogs. Tidal breathing peak expiratory flows were markedly higher in GRMD dogs. Abnormal abdominal motion was present in 7 of 10 (70%) GRMD dogs. Each technique provided objective, quantifiable measures that will be useful for monitoring respiratory function in GRMD dogs during clinical trials while avoiding the influence of sedation on results. Increased expiratory flows and the pattern of abdominal breathing are novel findings, not reported in people with Duchenne muscular dystrophy, and might be a consequence of hyperinflation.
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Affiliation(s)
- Justin C DeVanna
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, United States
| | - Joe N Kornegay
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Daniel J Bogan
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Janet R Bogan
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Jennifer L Dow
- Department of Pathology and Laboratory Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; Department of Neurology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States; The Gene Therapy Center, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, United States
| | - Eleanor C Hawkins
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, United States.
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