ORCID Profile
0000-0003-2910-9133
Current Organisation
Murdoch University
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Publisher: Wiley
Date: 20-03-2016
DOI: 10.1111/EVE.12162
Publisher: Frontiers Media SA
Date: 22-07-2022
DOI: 10.3389/FVETS.2022.946911
Abstract: Electrical impedance tomography (EIT) is a non-invasive real-time non-ionising imaging modality that has many applications. Since the first recorded use in 1978, the technology has become more widely used especially in human adult and neonatal critical care monitoring. Recently, there has been an increase in research on thoracic EIT in veterinary medicine. Real-time imaging of the thorax allows evaluation of ventilation distribution in anesthetised and conscious animals. As the technology becomes recognised in the veterinary community there is a need to standardize approaches to data collection, analysis, interpretation and nomenclature, ensuring comparison and repeatability between researchers and studies. A group of nineteen veterinarians and two biomedical engineers experienced in veterinary EIT were consulted and contributed to the preparation of this statement. The aim of this consensus is to provide an introduction to this imaging modality, to highlight clinical relevance and to include recommendations on how to effectively use thoracic EIT in veterinary species. Based on this, the consensus statement aims to address the need for a streamlined approach to veterinary thoracic EIT and includes: an introduction to the use of EIT in veterinary species, the technical background to creation of the functional images, a consensus from all contributing authors on the practical application and use of the technology, descriptions and interpretation of current available variables including appropriate statistical analysis, nomenclature recommended for consistency and future developments in thoracic EIT. The information provided in this consensus statement may benefit researchers and clinicians working within the field of veterinary thoracic EIT. We endeavor to inform future users of the benefits of this imaging modality and provide opportunities to further explore applications of this technology with regards to perfusion imaging and pathology diagnosis.
Publisher: Frontiers Media SA
Date: 09-06-2022
DOI: 10.3389/FVETS.2022.895268
Abstract: Equine respiratory physiology might be influenced by the presence of an endotracheal tube (ETT). This experimental, randomized cross-over study aimed to compare breathing pattern (BrP) and ventilation distribution in anesthetized horses spontaneously breathing room air via ETT or facemask (MASK). Six healthy adult horses were anesthetized with total intravenous anesthesia (TIVA xylazine, ketamine, guaiphenesin), breathing spontaneously in right lateral recumbency, and randomly assigned to ETT or MASK for 30 min, followed by the other treatment for an additional 30 min. During a second anesthesia 1 month later, the treatment order was inversed. Electrical impedance tomography (EIT) using a thoracic electrode belt, spirometry, volumetric capnography, esophageal pressure difference (ΔPoes), venous admixture, and laryngoscopy data were recorded over 2 min every 15 min. Breaths were classified as normal or alternate (sigh or crown-like ) according to the EIT impedance curve. A mixed linear model was used to test the effect of treatment on continuous outcomes. Cochran-Mantel-Haenszel analysis was used to test for associations between global BrP and treatment. Global BrP was associated with treatment ( p = 0.012) with more alternate breaths during ETT. The center of ventilation right-to-left (CoV RL ) showed more ventilation in the non-dependent lung during ETT ( p = 0.025). The I:E ratio ( p = 0.017) and ΔPoes ( p & 0.001) were smaller, and peak expiratory flow ( p = 0.009) and physiologic dead space ( p = 0.034) were larger with ETT. The presence of an ETT alters BrP and shifts ventilation toward the non-dependent lung in spontaneously breathing horses anesthetized with TIVA.
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.TVJL.2018.07.008
Abstract: Thyrotropin releasing hormone (TRH)-stimulation testing for pituitary pars intermedia dysfunction (PPID) in horses is only recommended at certain times of the year. Current diagnostic cut-off values reflect testing in the northern hemisphere during this time. The aims of this study were to evaluate TRH stimulation testing during two different phases of the circannual pituitary cycle and to determine whether diagnostic cut-off values developed in the northern hemisphere are appropriate in Australia. Thirteen clinically normal horses at Perth, Western Australia, and 23 horses at Townsville, Queensland, Australia, had TRH stimulation tests performed at two different time points during the circannual pituitary cycle. At both locations, post-TRH adrenocorticotropic hormone (ACTH) concentrations were significantly different between testing time points (Perth: P=0.001 Townsville: P<0.0001). In Perth, the mean ACTH concentrations 10min post-TRH in September and March were 51.4pg/mL (95% confidence interval, CI, 46.4-56.4pg/mL) and 248.5pg/mL (95% CI 170.2-326.9pg/mL), respectively. The median percentage change in ACTH concentrations in March was 361.9%. In Townsville, the mean ACTH concentrations 30min post-TRH in September and April were 35.3pg/mL (95% CI 29.6-40.9pg/mL) and 112.3pg/mL (95% CI 93.4-131.2pg/mL), respectively. The median percentage change in ACTH concentrations in April was 144.7%. The ACTH cut-off value after TRH stimulation in normal horses in September in Perth and Townsville was similar to the values established in the northern hemisphere. However, TRH stimulation testing in March/April was highly variable at both locations.
Publisher: Wiley
Date: 29-06-2017
DOI: 10.1111/JVIM.14782
Publisher: Wiley
Date: 06-10-2023
DOI: 10.1111/JVIM.16884
Publisher: Frontiers Media SA
Date: 05-07-2023
DOI: 10.3389/FPHYS.2023.1164646
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.
Publisher: Wiley
Date: 04-08-2021
DOI: 10.1111/JVIM.16227
Abstract: Left‐sided cardiac volume overload (LCVO) can cause fluid accumulation in lung tissue changing the distribution of ventilation, which can be evaluated by electrical impedance tomography (EIT). To describe and compare EIT variables in horses with naturally occurring compensated and decompensated LCVO and compare them to a healthy cohort. Fourteen adult horses, including university teaching horses and clinical cases (healthy: 8 LCVO: 4 compensated, 2 decompensated). In this prospective cohort study, EIT was used in standing, unsedated horses and analyzed for conventional variables, ventilated right (VA R ) and left (VA L ) lung area, linear‐plane distribution variables (avg‐max VΔZ Line , VΔZ Line ), global peak flows, inhomogeneity factor, and estimated tidal volume. Horses with decompensated LCVO were assessed before and after administration of furosemide. Variables for healthy and LCVO‐affected horses were compared using a Mann‐Whitney test or unpaired t ‐test and observations from compensated and decompensated horses are reported. Compared to the healthy horses, the LCVO cohort had significantly less VA L (mean difference 3.02 95% confidence interval .77‐5.2 P = .02), more VA R (−1.13 −2.18 to −.08 P = .04), smaller avg‐max VΔZ L Line (2.54 1.07‐4.00 P = .003) and VΔZ L Line (median difference 5.40 1.71‐9.09 P = .01). Observation of EIT alterations were reflected by clinical signs in horses with decompensated LCVO and after administration of furosemide. EIT measurements of ventilation distribution showed less ventilation in the left lung of horses with LCVO and might be useful as an objective assessment of the ventilation effects of cardiogenic pulmonary disease in horses.
Publisher: Wiley
Date: 07-12-2022
DOI: 10.1111/EVE.13603
Abstract: A 3‐year‐old Thoroughbred filly presented with a several‐month history of weight loss, polydipsia and polyuria, intermittent diarrhoea and behavioural changes and intermittently uncoordinated gait. Neurological examination revealed hyperexcitability, bilaterally reduced pupillary light reflexes and quadrilateral ataxia with proprioceptive deficits more obvious in the forelimbs than in the hindlimbs. A multifocal neurological lesion was suspected. The laboratory finding of a persistent hyperchloraemia and an apparent negative anion gap prompted measurement of serum bromide concentration and subsequently confirmed bromide intoxication. Further questioning of the trainer revealed that the filly had been administered oral potassium bromide for behavioural modification over several months. Clinical signs of bromide intoxication resolved within 20 days following the last bromide administration, without specific medical intervention. This case report describes the risk of inadvertent bromide overdosing in horses and highlights the need for control of bromide use in the equine industry.
Publisher: MDPI AG
Date: 03-07-2023
DOI: 10.3390/MICROORGANISMS11071743
Abstract: Clostridioides difficile poses an ongoing threat as a cause of gastrointestinal disease in humans and animals. Traditionally considered a human healthcare-related disease, increases in community-associated C. difficile infection (CDI) and growing evidence of inter-species transmission suggest a wider perspective is required for CDI control. In horses, C. difficile is a major cause of diarrhoea and life-threatening colitis. This study aimed to better understand the epidemiology of CDI in Australian horses and provide insights into the relationships between horse, human and environmental strains. A total of 752 faecal s les from 387 Western Australian horses were collected. C. difficile was isolated from 104 (30.9%) horses without gastrointestinal signs and 19 (37.8%) with gastrointestinal signs. Of these, 68 (55.3%) harboured one or more toxigenic strains, including C. difficile PCR ribotypes (RTs) 012 (n = 14), 014/020 (n = 10) and 087 (n = 7), all prominent in human infection. Whole-genome analysis of 45 strains identified a phylogenetic cluster of 10 closely related C. difficile RT 012 strains of equine, human and environmental origin (0–62 SNP differences average 23), indicating recent shared ancestry. Evidence of possible clonal inter-species transmission or common-source exposure was identified for a subgroup of three horse and one human isolates, highlighting the need for a One Health approach to C. difficile surveillance.
Publisher: Wiley
Date: 12-05-2023
DOI: 10.1111/EVE.13811
Abstract: The natural progression of equine glandular gastric disease (EGGD) in the absence of treatment has not yet been described in the literature, nor has the prevalence in a teaching herd population been reported. The aims of this study were to determine the prevalence of disease in a teaching population over the study period (2019–2021) and to observe the changes over time in disease severity of naturally occurring diseases (not experimentally induced) without medical intervention. Twenty‐one horses underwent an initial gastroscopy and a repeat gastroscopy between 14 and 731 days later. Gastroscopy data were graded quantitatively and described qualitatively. Prevalence and 95% confidence intervals (CI) were calculated. The changes over time were determined by comparing initial and repeat gastroscopies. The prevalence from initial, repeat and total number of gastroscopies was 62% (95% CI: 40.8–79.3), 71% (95% CI: 50.0–86.2) and 67% (95% CI: 51.6–79), respectively. The changes over time included worsening of disease in 29% of horses (95% CI: 13.8–50.0), improvement of disease to a lower grade in 24% (95% CI: 10.6–45.1), no change in grade in 38% (95% CI: 20.8–59.1), and complete resolution of disease to grade 0 in 10% (95% CI: 2.7–28.9). Limitations included a maximum of two gastroscopies per horse given COVID‐19 restrictions on data collection, and highly varied interval times between initial and repeat gastroscopies. In conclusion, there is a high prevalence of disease in this teaching herd. The changes over time in naturally occurring diseases without medical intervention might include worsening, improvement, no change or resolution of disease.
No related grants have been discovered for David Byrne.