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Background: Brachycephalic dogs display sleep-disordered breathing (SDB). The risk factors for SDB remain unknown., Objectives: To identify risk factors for SDB. We hypothesized that brachycephaly, increasing severity of brachycephalic obstructive airway syndrome (BOAS), excess weight, and aging predispose to SDB., Animals: Sixty-three privately owned pet dogs were prospectively recruited: 28 brachycephalic and 35 normocephalic (mesaticephalic or dolicocephalic) dogs., Methods: Prospective observational cross-sectional study with convenience sampling. Recording with the neckband was done over 1 night at each dog's home. The primary outcome measure was the obstructive respiratory event index (OREI). Body condition score (BCS) was assessed, and BOAS severity was graded for brachycephalic dogs., Results: Brachycephaly was a significant risk factor for high OREI value (ratio of the geometric means 5.6, 95% confidence interval [CI] 3.2-9.9; P < .001) but aging was not (1.1, 95% CI 1.0-1.2; P = .2). Excess weight, defined as a BCS of over 5/9, (3.5, 95% CI 1.8-6.7; P < .001) was a significant risk factor. In brachycephalic dogs, BOAS-positive class (moderate or severe BOAS signs) was a significant risk factor (2.5, 95% CI 1.1-5.6; P = .03)., Conclusions and Clinical Importance: Brachycephaly decreases welfare in a multitude of ways, including disrupting sleep. Brachycephaly, increasing severity of BOAS and excess weight are risk factors for obstructive SDB., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Reducing inhaled dust particles improves lung function in horses with severe asthma. Soaked hay is commonly used by owners, but its efficacy in improving lung function and inflammation has not been documented., Objectives: To measure the effects of soaked hay and alfalfa pellets in horses with severe asthma., Animals: Ten adult horses with severe asthma from a research colony., Methods: Prospective controlled trial. Horses in clinical exacerbation were housed indoors and allocated to be fed either soaked hay (n = 5) or alfalfa pellets (n = 5) for 6 weeks. Soaked hay was immersed for 45 minutes and dried out hay was discarded between meals. Pulmonary function and clinical scores were measured before and after 2, 4, and 6 weeks. Tracheal mucus scores and bronchoalveolar lavages were performed before and after 6 weeks. Lung function was analyzed with a linear mixed model using log-transformed data., Results: Lung resistance decreased from (median (range)) 2.47 (1.54-3.95) to 1.59 (0.52-2.10) cmH 2 O/L/s in the pellets group and from 1.89 (1.2-3.54) to 0.61 (0.42-2.08) cmH 2 O/L/s in the soaked hay group over the 6-week period for an average difference of 1.06 cmH 2 O/L/s for pellets (95% confidence interval [95% CI]: 0.09-2.04, P = .03, not significant after correction) and 1.31 cmH 2 O/L/s for soaked hay (95% CI: -0.23 to 2.85, P < .001, significant)., Conclusion and Clinical Importance: Soaked hay can control airway obstruction in horses with severe asthma. The strict protocol for soaking and discarding dried-out hay in this study could however be considered too great of an inconvenience by owners., (© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Background: Aerodigestive diseases (AeroD), hybrid disorders between the respiratory and gastrointestinal (GI) tracts, may present without GI signs. Sliding hiatal hernia (sHH) is an important AeroD in brachycephalic dogs linked to respiratory pathology. The spectrum of other AeroD and respiratory clinical signs (CS) in brachycephalic and nonbrachycephalic dogs with sHH is unknown., Objectives: Characterize CS of AeroD in dogs with sHH, compare CS between brachycephalic and nonbrachycephalic dogs, and compare thoracic radiographs and videofluoroscopic swallow study (VFSS) for diagnosing sHH., Animals: Sixty-seven client-owned dogs with sHH., Methods: Medical records of dogs with sHH presented to the veterinary teaching hospitals at Auburn University and the University of Missouri between 1 January 2009 and 31 December 2020 were retrospectively reviewed. Between group, comparisons were made using Mann-Whitney test, Chi-square analysis, and Spearman correlation (P < .05)., Results: Dogs with sHH presented with exclusively GI signs (28/67), mixed respiratory and GI signs (22/67), or with exclusively respiratory signs (17/67). Wheras brachycephalic dogs were not significantly more likely to present with respiratory CS (P = .145), they were younger (P < .001), and more likely to present in respiratory distress (P = .02), and with radiographic evidence of aspiration pneumonia (P < .001) compared to nonbrachycephalic dogs. Six of 12 dogs with normal thoracic radiographs having sHH presented with respiratory CS. For detection of sHH, VFSS was superior to radiographs (P < .001)., Conclusions and Clinical Importance: Dogs with sHH may present with exclusively respiratory signs. Respiratory signs may be more severe in brachycephalic compared to nonbrachycephalic dogs. Videofluoroscopic swallow study was superior to thoracic radiographs for detection of sHH in dogs., (© 2022 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.)

Background: Brachycephalic dogs have abnormal breathing patterns similar to those in humans with obstructive sleep apnea syndrome. Obstructive sleep apnea syndrome is associated with dyslipidemia, hyperglycemia, and insulin resistance. Despite the fact that anatomic and functional alterations are well described in brachycephalic dogs, little is known about the consequences of upper airway obstruction on systemic inflammatory response and metabolic profile., Objectives: To describe history, clinical presentation, and anatomic abnormalities; to evaluate systemic inflammatory response and metabolic profile; and to identify possible associations among clinical signs, anatomic abnormalities, inflammatory response, and metabolic profile in brachycephalic dogs with airway obstruction., Animals: Thirty purebred brachycephalic dogs with brachycephalic airway obstructive syndrome (BAOS)., Methods: Prospective study. The following information was recorded and studied: respiratory and digestive signs, airway and digestive endoscopic anomalies, presence or absence of tracheal hypoplasia, histologic evaluation of gastrointestinal tract biopsy specimens, serum concentrations of C-reactive protein (CRP), fructosamine, insulin, glucose, triglyceride, cholesterol, and plasma concentrations of lipoprotein classes., Results: A high proportion of dogs (76.7%) had gastrointestinal signs. Esophageal deviation, atony of the cardia of the stomach, and distal esophagitis were the most common endoscopic anomalies detected. Twenty-six (86.6%) dogs had different degrees of laryngeal collapse. Gastrointestinal histologic evaluation identified mostly chronic inflammation. Glucose, fructosamine, triglycerides, cholesterol, CRP, pre-beta, beta lipoproteins, and chylomicrons were increased to a variable extent. Significant associations among clinical signs, anatomic abnormalities, CRP, and metabolic profile were not found., Conclusion and Clinical Importance: Despite the presence of inflammation and some mild metabolic derangements, the clinicopathological variables evaluated did not offer valuable information in dogs with BAOS., (© 2019 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Bronchoalveolar lavage (BAL) fluid cytology and culture are used to characterize respiratory diseases in dogs. Little is known about disorders associated with increased numbers of lymphocytes in BAL fluid., Objective: To evaluate duration of clinical signs and detection of specific respiratory diagnoses in dogs with BAL lymphocytosis., Animals: One-hundred four client-owned dogs evaluated for respiratory signs., Methods: Medical records of dogs that had >300 cells/μL and >20% lymphocytes on a differential cell count of BAL fluid between January 1, 2006, and January 1, 2016, were reviewed retrospectively. Cases were evaluated for the duration of clinical signs and respiratory diagnoses, including aspiration injury, infectious or inflammatory respiratory disease, and airway collapse., Results: Dogs ranged in age from 0.5 to 16 years (median, 7.9 years) and had a median body weight of 11.4 kg (range, 2.0-42.7 kg). Eosinophilic lung disease was documented in 13 of 104 dogs (Group 1) and airway neutrophilia associated with infectious or inflammatory disease was found in 59 of 104 dogs (Group 2). Lymphocytosis alone in BAL fluid was described in 32 dogs (Group 3). Duration of cough did not differ among groups, but airway collapse was significantly more common in dogs with solitary lymphocytosis than in those with other types of inflammation., Conclusions and Clinical Importance: Lymphocytosis in BAL fluid is common in dogs and, in many cases, likely represents a common response to airway injury, independent of the type or duration of insult. It is unknown whether airway collapse leads to lymphocytosis or if the inflammatory process causes airway collapse., (© 2019 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Heliox, a mixture of helium and oxygen, alleviates airway obstruction in people and improves air flow, and its use has been proposed in dogs. Brachycephalic dogs have naturally occurring airway obstruction where heliox might be a useful therapeutic option., Objective: The purposes of this study were to (1) determine the impact of breathing heliox on peak inspiratory and expiratory flows (PIF/PEF) in healthy dogs and (2) determine if brachycephalic dogs and mesocephalic dogs have similar responses to inhaled heliox., Animals: Eleven healthy dogs: 5 mesocephalic and 6 brachycephalic dogs., Methods: A prospective study. Tidal breathing flow-volume loops were recorded when dogs were breathing room air (nitrogen-oxygen) and heliox. Peak inspiratory and expiratory flow rates were recorded and the subjective shape of loops assessed. Peak inspiratory and expiratory flows pre- and post-heliox were compared using a Mann-Whitney Rank sum test with a P-value of <.05 considered significant., Results: In inhaled heliox, PIF and PEF were evaluated by tidal breathing flow-volume loops. In mesocephalic dogs, PIF increased from a median of 820 mL/s (range, 494-1010 mL/s) to 1386 mL/s; P = .02; and for PEF from 688 mL/s to 1793 mL/s (P = .04), whereas in brachycephalic dogs, the median PIF increased from 282 mL/s to 694 mL/s; P = .01 and the median PEF increased from 212 mL/s to 517 mL/sec; P = .03. Brachycephalic dogs showed normalization of loop shapes., Conclusions and Clinical Importance: Heliox improves flow rate and appears to improve flow patterns in brachycephalic dogs., (© 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: A novel test using whole-body barometric plethysmography (WBBP) was developed recently to diagnose brachycephalic obstructive airway syndrome (BOAS) in unsedated French bulldogs., Hypothesis/objectives: The hypotheses of this study were: (1) respiratory characteristics are different between healthy nonbrachycephalic dogs and brachycephalic dogs; and among pugs, French bulldogs, and bulldogs; and (2) obesity and stenotic nares are risk factors for BOAS. The main objective was to establish a diagnostic test for BOAS in these 3 breeds., Animals: A total of 266 brachycephalic dogs (100 pugs, 100 French bulldogs, and 66 bulldogs) and 28 nonbrachycephalic dogs., Methods: Prospective study. Exercise tolerance tests with respiratory functional grading, and WBBP were performed on all dogs. Data from WBBP were associated with functional grades to train quadratic discriminant analysis tools to assign dogs to BOAS+ and BOAS- groups. A BOAS index (0-100%) was calculated for each dog. Receiver operating characteristic (ROC) curves were used to evaluate classification ability., Results: Minute volume was decreased significantly in asymptomatic pugs (P = .009), French bulldogs (P = .026), and bulldogs (P < .0001) when compared to nonbrachycephalic controls. Respiratory characteristics were different among breeds and affected dogs had a significant increase in trace variation. The BOAS index predicted BOAS status for each breed with 94-97% (95% confidence interval [CI], 88.9-100%) accuracy (area under the ROC curve). Both obesity (P = .04) and stenotic nares (P = .004) were significantly associated with BOAS., Conclusions and Clinical Importance: The WBBP can be used as a clinical tool to diagnose BOAS noninvasively and objectively., (Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.)

Background: Systemic oxidative stress in horses with recurrent airway obstruction (RAO) is poorly characterized., Objectives: The goal of this study was to investigate whether equine RAO is associated with systemic disturbances in the oxidant-antioxidant equilibrium., Animals: Seven healthy horses and 7 horses with symptomatic RAO., Methods: A prospective study. Healthy and RAO-affected horses were exposed to a 48-hour challenge with moldy hay and straw to induce clinical exacerbation of RAO. Venous blood was collected and the activities of the superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in equine erythrocyte lysates were measured. The concentration of thiobarbituric acid-reactive substances (TBARSs) was assessed both in erythrocyte lysates and in plasma., Results: A significant increase in the activities of GPx and SOD was detected in RAO-affected horses compared with the control animals. There was no significant difference between groups in terms of the erythrocyte lysate activities of CAT, GR, or TBARs or the plasma concentration of TBARs., Conclusion and Clinical Importance: Our results support the hypothesis that RAO in horses is associated with systemic oxidative stress. Future studies are needed to assess whether horses suffering from RAO can benefit from antioxidant supplementation., (Copyright © 2014 by the American College of Veterinary Internal Medicine.)

Background: It is often assumed that horses with mild respiratory clinical signs, such as mucous nasal discharge and occasional coughing, have an increased risk of developing recurrent airway obstruction (RAO)., Hypothesis: Compared to horses without any clinical signs of respiratory disease, those with occasional coughing, mucous nasal discharge, or both have an increased risk of developing signs of RAO (frequent coughing, increased breathing effort, exercise intolerance, or a combination of these) as characterized by the Horse Owner Assessed Respiratory Signs Index (HOARSI 1-4)., Animals: Two half-sibling families descending from 2 RAO-affected stallions (n = 65 and n = 47) and an independent replication population of unrelated horses (n = 88)., Methods: In a retrospective cohort study, standardized information on occurrence and frequency of coughing, mucous nasal discharge, poor performance, and abnormal breathing effort-and these factors combined in the HOARSI-as well as management factors were collected at intervals of 1.3-5 years., Results: Compared to horses without clinical signs of respiratory disease (half-siblings 7%; unrelated horses 3%), those with mild respiratory signs developed clinical signs of RAO more frequently: half-siblings with mucous nasal discharge 35% (P < .001, OR: 7.0, sensitivity: 62%, specificity: 81%), with mucous nasal discharge and occasional coughing 43% (P < .001, OR: 9.9, sensitivity: 55%, specificity: 89%); unrelated horses with occasional coughing: 25% (P = .006, OR = 9.7, sensitivity: 75%, specificity: 76%)., Conclusions and Clinical Importance: Occasional coughing and mucous nasal discharge might represent an increased risk of developing RAO., (Copyright © 2014 by the American College of Veterinary Internal Medicine.)

Background: Norwich Terriers have grown increasingly popular as show animals and pets, and awareness of respiratory problems within the breed is growing., Objective: To describe components of obstructive upper airway syndrome in a nonbrachycephalic terrier breed., Animals: Sixteen Norwich Terriers; 12 with and 4 without clinical signs of respiratory disease., Methods: Prospective case series. Physical and laryngoscopic examinations were performed by 1 investigator in all dogs. Medical and surgical interventions were summarized and results of follow-up examination or owner reports were recorded., Results: The study population was comprised of 9 females (6 intact) and 7 males (5 intact). Median age was 3.0 years (range, 0.5-11 years). Of 12 dogs presented for a respiratory complaint, physical examination was normal in 4 dogs. Laryngoscopic examination was abnormal in 11/12 dogs with redundant supra-arytenoid folds, laryngeal collapse, everted laryngeal saccules, and a narrowed laryngeal opening in most. Of 4 dogs lacking clinical signs, all had normal physical examination; however, 3/4 dogs had similar appearance of the larynx to dogs with clinical signs. Response to surgical intervention was minimal to moderate in all dogs., Conclusions and Clinical Importance: Norwich Terriers suffer from an upper airway obstructive syndrome that differs from that encountered in brachycephalic breeds. Affected dogs are difficult to identify without laryngoscopic examination because of the lack of clinical signs and abnormalities in physical examination findings, despite severe airway obstruction. Care is warranted when anesthetizing Norwich Terriers because of the small size of the laryngeal opening., (Copyright © 2013 by the American College of Veterinary Internal Medicine.)

Background: Tracheoscopy is generally used for the diagnosis of tracheal collapse (TC) in dogs; yet, it is costly, requires anesthesia, and can irritate the airway. The tidal breathing flow-volume loop (TBFVL) is a safe, quick, and noninvasive pulmonary function test currently used in humans., Hypothesis: TBFVL will differentiate dogs with TC from healthy controls and contribute to disease grading., Animals: Twenty-eight dogs with naturally occurring TC and 10 healthy controls., Methods: Cross-sectional, prospective clinical study: The 38 dogs were assigned to one of 4 groups based on tracheoscopy results: group A (n=10, healthy controls), group B (n=10, grade I TC), group C (n=10, grade II TC), and group D (n=8, grade III TC). The TBFVL measurement was performed on all dogs and loops were assessed for their shape. Forty-four TBFVL parameters were calculated., Results: Two types of TBFVL shapes were identified: Type I, representative of the 10 healthy controls, and Type II, representative of the 28 dogs with TC. Statistical analysis showed the dogs could be differentiated into healthy or affected by TC by 3 indices, TE/TI (expiratory time divided by inspiratory time), TI/TTOT (inspiratory time divided by total respiratory time), and EF75/IF75 (expiratory flow at end tidal volume plus 75% end tidal volume divided by inspiratory flow at end tidal volume plus 75% end tidal volume). The TC could also be graded as mild-moderate (grades I and II) or severe (grade III), showing a diagnostic value of 97.4%., Conclusion and Clinical Importance: TBFVL is accurate, quick, noninvasive, and safe and can contribute to the diagnosis of TC in dogs.

Mucus accumulation and neutrophilic inflammation in the airways are hallmarks of heaves. Endoscopically visible mucus accumulations, however, have not been studied during exposure to dusty hay and allergens (ie, environmental challenge). We hypothesized that (1) heaves-affected horses have increased mucus accumulation compared with controls, (2) mucus accumulations increase in heaves-affected horses during environmental challenge, and (3) environmental challenge also induces neutrophilic inflammation and mucus accumulation in control horses. Mucus accumulation was graded endoscopically (mucus grades [MGs] 1-5), and airway inflammation was evaluated by bronchoalveolar lavage fluid (BALF) cytology before (0 hours) and during (6, 24, 48 hours) environmental challenge. Large amounts of mucus (MG 4-5) were specific for heaves-affected horses in this study. Variation among controls was considerable, however, and intermediate grades (MG 2-3) were nonspecific, showing complete overlap between the 2 groups. Median mucus accumulations (25th, 75th percentiles) increased in heaves-affected horses from MG 2.5 (1.5, 3.5) at baseline to MG 3.5 (2.0, 4.0), 4.0 (3.0, 4.0), and 4.0 (4.0, 4.0) at 6, 24, and 48 hours, respectively. MG values did not increase in controls--overall MG 1.0 (1.0, 2.0)--even though controls also showed a moderate increase of BALF neutrophils. Mucus accumulations before and especially after exposure to dust and allergens are increased in heaves-affected horses compared with controls. Healthy controls show considerable variability in mucus accumulation but, despite an influx of neutrophils into the airways, no increase of mucus accumulation after exposure to hay dust.

The results of clinical and pulmonary functional evaluation of 24 cats with bronchopulmonary disease and 15 healthy cats are presented. Affected cats had historical evidence of excessive reflexes (coughing, sneezing); physical evidence of airway secretions (crackles), obstruction (wheezing), and increased tracheal sensitivity; radiographic evidence of bronchial and interstitial lung disease; and cytological evidence of airway inflammation or mucous secretions. Bacterial isolates from healthy and affected cats were predominantly Gram-negative rods, indicating that bronchi of cats are not always sterile and that normal flora should be considered in interpreting cultures from cats with suspected bronchopulmonary disease. Cats were grouped according to relative disease severity based on scored historical, physical, and radiographic abnormalities. The mean (+/- standard deviation) baseline lung resistance measurement in healthy cats was 28.9 cm H2O/L/s (+/- 6.2 cm H2O/L/s), whereas in mildly, moderately, and severely affected cats it was 38.3 cm H2O/L/s (+/- 21.5 cm H2O/L/s), 44.8 cmH2O/L/s (+/- 7.7 cm H2O/L/s), and 105.2 cm H2O/L/s (+/- 66.9 cm H2O/L/s), respectively. In healthy cats, dynamic lung compliance was 19.8 (+/- 7.4), whereas in mildly, moderately, and severely affected cats it was 14.7 mL/cm H2O (+/- 3.8 mL/cm H2O), 17.7 mL/cm H2O (+/- 6.9 mL/cm H2O), and 13.0 mL/cm H2O (+/- 7.9 mL/cm H2O), respectively. Thus, airway obstruction was present in many of the affected cats. Based on acute response to the bronchodilator, terbutaline, airway obstruction was partially reversible in many affected cats, although the degree of reversibility varied. Furthermore, based on bronchoprovocation testing, 6 (of 7) affected cats evaluated also had increased airway responsiveness to aerosolized methacholine.