Pulmonary health in horses encompasses the study of the respiratory system's function, structure, and disorders within equine species. This area of research addresses various conditions affecting the lungs and airways, such as equine asthma, exercise-induced pulmonary hemorrhage (EIPH), and infectious respiratory diseases. The respiratory system's efficiency is vital for horses, particularly those involved in athletic activities, as it influences performance and overall well-being. Research in pulmonary health investigates diagnostic methods, treatment options, and preventive measures for maintaining respiratory function in horses. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and pathophysiology of the equine respiratory system, as well as the management and therapeutic approaches for respiratory conditions in horses.
Derksen F, Williams K, Stack A.While airway endoscopy and bronchoalveolar lavage are the methodsof choice for diagnosing exercise-induced pulmonary hemorrhage (EIPH), these techniques do not allow accurate evaluation of the severity of bleeding. EIPH pathology is characterized by occlusive remodeling of pulmonary veins. Affected veins have large collagen deposits in their walls, which reduces their lumens. In the caudodorsal regions, pulmonary vein wall remodeling is associated with hemosiderin accumulation, bronchial circulation angiogenesis, and fibrosis of the alveolar interstitium, bronchovascular bundle, septa, and ple...
Veres-Nyéki KO, Graubner C, Aloisio F, Spadavecchia C.After an uneventful general anesthesia, in a horse negative pressure pulmonary edema developed due to acute upper airway obstruction during the anesthetic recovery phase after colic surgery. No pathologic alteration of respiration was observed until the horse stood up and began suffocating. The horse had recovered with the nasogastric tube in situ. This, together with the postmortem diagnosis of laryngeal hemiplegia resulted in impairment of airflow through the larynx and development of pulmonary edema. Our objective is to alert clinicians about the possible hazard of recovery with an in-situ ...
van der Geize R, Grommen AW, Hessels GI, Jacobs AA, Dijkhuizen L.Rhodococcus equi causes fatal pyogranulomatous pneumonia in foals and immunocompromised animals and humans. Despite its importance, there is currently no effective vaccine against the disease. The actinobacteria R. equi and the human pathogen Mycobacterium tuberculosis are related, and both cause pulmonary diseases. Recently, we have shown that essential steps in the cholesterol catabolic pathway are involved in the pathogenicity of M. tuberculosis. Bioinformatic analysis revealed the presence of a similar cholesterol catabolic gene cluster in R. equi. Orthologs of predicted M. tuberculosis vi...
Richard EA, Pitel PH, Christmann U, Lekeux P, Fortier G, Pronost S.Surfactant protein D (SP-D), mainly synthesised by alveolar type II cells and nonciliated bronchiolar cells, is one important component of innate pulmonary immunity. In man, circulating concentrations of SP-D are routinely used as biomarkers for pulmonary injury. To date, serum SP-D levels have only been investigated in horses in an experimental model of bacterial airway infection. Objective: To compare serum SP-D concentrations at rest and after exercise in horses with and without inflammatory airway disease (IAD). Methods: Venous blood samples were collected from 42 Standardbred racehorses a...
Hubbell JA, Aarnes TK, Bednarski RM, Lerche P, Muir WW.The purpose of this study was to compare the effects of 0.5 fraction of inspired oxygen (FiO₂) and >0.95 FiO₂ on pulmonary gas exchange, shunt fraction and oxygen delivery (DO₂) in dorsally recumbent horses during inhalant anesthesia. The use of 0.5 FiO₂ has the potential to reduce absorption atelectasis (compared to maximal FiO₂) and augment alveolar oxygen (O₂) tensions (compared to ambient air) thereby improving gas exchange and DO₂. Our hypothesis was that 0.5 FiO₂ would reduce ventilation-perfusion mismatching and increase the fraction of pulmonary blood flow that is ox...
Jean D, Vrins A, Beauchamp G, Lavoie JP.To determine variations in cytologic counts of bronchoalveolar lavage (BAL) fluid attributable to month of collection, first and second aliquots, and left and right lung sites in horses with recurrent airway obstruction (RAO). Methods: 5 horses with RAO and 5 healthy horses without respiratory tract disease. Methods: Horses were housed in a stable for 5 months prior to and throughout the study. Bronchoalveolar lavage fluid was collected from the right and left lung of each horse 3 times at monthly intervals (February, March, and April). Each BAL fluid collection was performed by use of 2 incre...
Vengust M, Stämpfli H, De Moraes AN, Teixeiro-Neto F, Viel L, Heigenhauser G.Carbonic anhydrase (CA) catalyses the hydration/dehydration reaction of CO(2) and increases the rate of Cl(-) and HCO(3)(-) exchange between the erythrocytes and plasma. Therefore, chronic inhibition of CA has a potential to attenuate CO(2) output and induce greater metabolic and respiratory acidosis in exercising horses. Objective: To determine the effects of Carbonic anhydrase inhibition on CO(2) output and ionic exchange between erythrocytes and plasma and their influence on acid-base balance in the pulmonary circulation (across the lung) in exercising horses with and without CA inhibition....
Colahan PT, Jackson CA, Rice B, Szabo N, Jones JH.Sildenafil, a phosphodiesterase-5 inhibitor vasodilator, increases cGMP concentrations by inhibiting enzymatic degradation. Marketed to treat erectile dysfunction in men, it also reduces pulmonary arterial pressure (PAP). Because it reduces PAP, sildenafil may enhance performance and/or prevent exercise induced-pulmonary haemorrhage (EIPH). Objective: To determine if sildenafil citrate administration altered commonly measured indices of performance or reduced EIPH in exercised horses. Methods: Thirteen athletically conditioned Thoroughbred horses (2 mares and 11 geldings, age 3-12 years) were ...
Buchholz BM, Murdock A, Bayly WM, Sides RH.The antifibrinolytic, 6-aminohexanoic acid, also named aminocaproic acid (ACA), has been used empirically as a treatment for exercise-induced pulmonary haemorrhage (EIPH) on the unsubstantiated basis that transient coagulation dysfunction may contribute to its development. Objective: To assess the effect of ACA on bronchoalveolar lavage fluid (BALF) erythrocyte counts in horses performing treadmill exercise at an intensity greater than that needed to reach maximal oxygen consumption. Methods: Eight Thoroughbreds were exercised to fatigue 3 times on a 10% inclined treadmill at a speed for which...
McKane SA, Slocombe RF.Histological studies of exercise-induced pulmonary haemorrhage (EIPH) reveals inflammatory infiltrates within areas of lung that contain haemorrhage. This has resulted in the hypothesis that pulmonary inflammation could cause EIPH or contribute to an increased risk or severity of EIPH. Objective: To determine whether experimentally-induced pulmonary inflammation predisposes the lung to haemorrhage during exercise, by evaluating the bronchoalveolar lavage (BAL) cytology of normal and inflamed regions of lung following high speed treadmill exercise. Methods: Transendoscopic airway inoculations o...
Ramseyer A, Sides R, Slinker B, Evans D, Bayly W.The ability to obtain breath-by-breath measures of ventilatory mechanics for the entirety of an exercise test, regardless of speed(s) or duration enables evaluations of equine ventilation during exercise that are necessary for assessments of performance. Objective: Evaluation of a new ergospirometer (Quadflow; QF) system's accuracy and repeatability for measuring pulmonary variables in contrast to the established pneumotachometer-based system (control) and assessment of its effects, if any, on exercise capacity at high speeds. Methods: Five Thoroughbred horses each performed 10 incremental exe...
Joubert P, Cordeau ME, Lavoie JP.Heaves in horses is characterized by lower airway neutrophilic inflammation, and reversible airflow obstruction. Pulmonary macrophages contribute to the inflammation observed in a number of human and animal pulmonary diseases, and it has been postulated that they are responsible for the neutrophilic inflammation present in heaves by the release of cytokines and chemokines. To test this hypothesis, the mRNA expression of TNF-α, IL-1β, IL-8, and MIP-2 by macrophages isolated from bronchoalveolar lavage cells was quantified using real-time RT-PCR in horses with heaves (n-6) and controls (n-6). ...
Credille BC, Giguère S, Berghaus LJ, Burton AJ, Sturgill TL, Grover GS, Donecker JM, Brown SA.The objectives of this study were to determine the plasma and pulmonary disposition of ceftiofur crystalline free acid (CCFA) in weanling foals and to compare the plasma pharmacokinetic profile of weanling foals to that of adult horses. A single dose of CCFA was administered intramuscularly to six weanling foals and six adult horses at a dose of 6.6 mg/kg of body weight. Concentrations of desfuroylceftiofur acetamide (DCA) were determined in the plasma of all animals, and in pulmonary epithelial lining fluid (PELF) and bronchoalveolar lavage (BAL) cells of foals. After intramuscular (IM) admin...
McCoy AM, Hackett ES, Wagner AE, Mama KR, Hendrickson DA.To characterize pulmonary gas exchange and arterial lactate in horses with gastrointestinal disease undergoing anesthesia, compared with elective surgical horses, and to correlate these variables with postoperative complications and mortality. Methods: Prospective clinical study. Methods: Horses undergoing emergency laparotomy for acute intestinal disease (n = 50) and healthy horses undergoing elective surgery in dorsal recumbency (n = 20). Methods: Arterial blood gas analysis was performed at predetermined intervals on horses undergoing a standardized anesthetic protocol. Alveolar-arterial ox...
Berghaus LJ, Giguère S, Sturgill TL, Bade D, Malinski TJ, Huang R.The objectives of this study were to determine the plasma and pulmonary disposition of gamithromycin in foals and to investigate the in vitro activity of the drug against Streptococcus equi subsp. zooepidemicus (S. zooepidemicus) and Rhodococcus equi. A single dose of gamithromycin (6 mg/kg of body weight) was administered intramuscularly. Concentrations of gamithromycin in plasma, pulmonary epithelial lining fluid (PELF), bronchoalveolar lavage (BAL) cells, and blood neutrophils were determined using HPLC with tandem mass spectrometry detection. The minimum inhibitory concentration of gamithr...
Bertin FR, Ivester KM, Couëtil LL.Studies investigating the clinical efficacy of albuterol administered with the same propellant and commercially available delivery devices in horses with recurrent airway obstruction (RAO) are not currently available. Objective: To determine the efficacy of aerosolised albuterol administered to horses with RAO by means of 2 commercially available, hand-held delivery devices. Methods: Ten horses with RAO were kept in a dusty environment and fed mouldy hay to induce airway obstruction. Lung mechanics were measured before and after the procedure. ΔP(max) was measured 5 min after administration o...
Bringewatt T, Hopster K, Kästner SB, Rohn K, Ohnesorge B.The influence of a modified open lung concept (mOLC) on pulmonary and cardiovascular function during total intravenous anaesthesia (TIVA) in horses was evaluated. Forty-two warmblood horses (American Society of Anesthesiologists class 1 to 2), scheduled for elective surgery (mean [sd] weight 526 [65] kg, age 6.4 [5.4] years) were randomly divided into three groups: ventilation with mOLC, intermittent positive-pressure ventilation (IPPV), and spontaneous breathing. Premedication (0.8 mg/kg xylazine), induction (2.2 mg/kg ketamine and 0.05 mg/kg diazepam) and maintenance of anaesthesia with TIVA...
Poole DC, Erickson HH.Evolutionary forces drive beneficial adaptations in response to a complex array of environmental conditions. In contrast, over several millennia, humans have been so enamored by the running/athletic prowess of horses and dogs that they have sculpted their anatomy and physiology based solely upon running speed. Thus, through hundreds of generations, those structural and functional traits crucial for running fast have been optimized. Central among these traits is the capacity to uptake, transport and utilize oxygen at spectacular rates. Moreover, the coupling of the key systems--pulmonary-cardio...
Matera MG, Calzetta L, Rogliani P, Bardaro F, Page CP, Cazzola M.Equine obstructive pulmonary disease, also known as heaves or recurrent airway obstruction (RAO) is a common equine pulmonary disease with some similarities to human asthma and COPD, which represents a major cause of morbidity and loss of lung performance. Salbutamol has been widely used for the treatment of human airway diseases and has usually been prepared as the racemic form of the drug. However, recently the R-enantiomer of salbutamol has been introduced into clinical practice in the treatment of asthma in humans and this has been suggested to be an improvement on the racemic form of the ...
Winther L, Baptiste KE, Friis C.Ampicillin concentrations in pulmonary epithelial lining fluid (PELF) and plasma was studied after single intravenous ampicillin administration (15mg/kg) or single intragastric administration of its prodrug, pivampicillin (19.9mg/kg) to horses and discussed in relation to minimum inhibitory concentrations (MIC) of common equine respiratory pathogens. After intravenous administration, elimination of ampicillin was fast and not detectable in plasma after 12h in three out of six horses. Pivampicillin was absorbed well in non-fasted horses with an oral bioavailability of 36%. The degree of penetra...
Winther L, Baptiste KE, Friis C.Cefquinome concentrations, following intravenous and aerosol administration to horses, in pulmonary epithelial lining fluid (PELF) were examined and compared to plasma concentrations. Single dose of cefquinome sulphate (1 mg/kg) was administered intravenously to six horses followed by a single aerosol administration (225 mg) with a wash-out period of 14 days between treatments. After each drug administration, cefquinome concentrations in plasma and PELF, obtained by intrabronchial cotton swabs, were determined. After intravenous administration, cefquinome concentrations in plasma declined fast...
Schoster A, Anderson ME.A 9-year-old Quarter horse was presented for chronic refractory pneumonia. On necropsy, an hepatic abscess, caudal vena cava thrombosis, pulmonary thromboembolism, and embolic pneumonia were identified. Similar lesions have been reported in cattle as caudal vena cava thrombosis syndrome, however this syndrome has not previously been reported in horses. Un cheval Quarter horse âgé de 9 ans est présenté pour une pneumonie réfractaire chronique. À la nécropsie, un abcès hépatique, une thrombose de la veine cave caudale, un thromboembolisme pulmonaire et une pneumonie embolique ont été...
Leclere M, Lavoie-Lamoureux A, Gélinas-Lymburner E, David F, Martin JG, Lavoie JP.Recent studies suggest that airway smooth muscle remodeling is an early event in asthma, but whether it remains a dynamic process late in the course of the disease is unknown. Moreover, little is known about the effects of an antigenic exposure on chronically established smooth muscle remodeling. We measured the effects of antigenic exposure on airway smooth muscle in the central and peripheral airways of horses with heaves, a naturally occurring airway disease that shares similarities with chronic asthma. Heaves-affected horses (n = 6) and age-matched control horses (n = 5) were kept on pastu...
Vengust M, Kerr C, Staempfli HR, Pringle J, Heigenhauser GJ, Viel L.Frusemide (Fru) is widely prescribed for management of racehorses experiencing EIPH. The effect of Fru in the lung appears to be a reduction in transcapillary pressures and inhibition of the erythrocyte anion exchange, which may lead to attenuation of transpulmonary fluid fluxes during exercise. Objective: Treatment with Fru will attenuate transpulmonary fluid fluxes in horses during high intensity exercise. Methods: In a crossover study, 6 race-fit Standardbred horses were treated with 250 mg of Fru i.v. (FruTr) or placebo (Con) 4 h before exercise on a high speed treadmill until fatigue. Art...
Lyle CH, Uzal FA, McGorum BC, Aida H, Blissitt KJ, Case JT, Charles JT, Gardner I, Horadagoda N, Kusano K, Lam K, Pack JD, Parkin TD, Slocombe RF....To improve the understanding of exercise related sudden death in Thoroughbred racehorses. Objective: To describe the post mortem findings in cases of sudden death associated with exercise in 268 Thoroughbred racehorses. Methods: Gross and histological post mortem findings of 268 cases of sudden death were collated and reviewed. Cases originated from 6 racing jurisdictions around the world. Sudden death was defined as acute collapse and death in a closely observed and previously apparently healthy Thoroughbred racehorse, during, or within one hour after, exercise. Cause of death as determined b...
Winther L, Guardabassi L, Baptiste KE, Friis C.Sulfadiazine (SDZ) and trimethoprim (TMP) concentrations were examined in plasma and pulmonary epithelial lining fluid (PELF), following intravenous and oral administration and compared to minimum inhibitory concentrations (MICs) of common bacterial isolates from equine lower airway infections. SDZ/TMP (25/5 mg/kg) was administered intravenously, intragastric or per os to fed horses, and blood samples were collected before and 11 times, over 24 h, after administration. PELF samples were collected via a tampon device four times after drug administration and analysed for drug concentrations. Add...
Winther L, Honoré Hansen S, Baptiste KE, Friis C.Doxycycline concentrations, following two types of oral administration to horses, in pulmonary epithelial lining fluid (PELF) were examined and compared to plasma concentrations. The oral bioavailability was estimated from plasma concentrations achieved after an intravenous study in two horses. Doxycycline (10 mg/kg) was administered either intragastric or as topdressing to nonfasted horses. Blood samples were collected for drug analysis, before and 11 times after administration during 24 h. PELF samples were collected by a tampon device four times after drug administration and analysed for do...
Evans DL, Kiddell L, Smith CL.Inflammatory airway disease (IAD) is common in racehorses, and is a cause of wastage in the industry. IAD has been diagnosed by measurement of percent neutrophils (N%) in tracheal aspirates (TA). The aim of this study was to investigate whether spirometric indices of pulmonary function were correlated with N% in TAs. Limits to breathing were measured by analyses of relationships between relative times and relative respiratory gas flows during inspiration and expiration in individual breaths recorded after exercise. Horses with higher N% had significantly lower relative gas flows at the same re...
Vandenput S, Votion D, Duvivier DH, Van Erck E, Anciaux N, Art T, Lekeux P.The aim of this study was to evaluate the respiratory function of horses affected with chronic obstructive pulmonary disease (COPD) when maintained in a barn on wood shavings and fed grass silage for a period of 6 weeks. The mechanics of breathing, blood gas analysis and bronchial reactivity were examined on five horses with COPD at the end of the environment-controlled period (Period B) and the results compared with values obtained after 2 months at pasture (Period A) and after the onset of clinical signs of acute crisis (Period C). The results showed that clinical and functional parameters w...
Riihimäki M, Lilliehöök I, Raine A, Berg M, Pringle J.The aim of this study was to assess clinical signs and altered pulmonary cell expression of cytokines related to eosinophil kinetics in horses with pulmonary eosinophilia. Pulmonary eosinophilia was detected by bronchoalveolar lavage (BAL) in a group of standardbreds in training. Horses had detailed clinical examination, bronchoscopy, endobronchial biopsy and BAL on three occasions at approximately 6 month intervals. During the second sampling period BAL eosinophils were significantly elevated (p>0.010), with five horses having from 5% to 37% eosinophils in BAL. Neither detailed clinical ex...
Pusterla N, Pesavento PA, Leutenegger CM, Hay J, Lowenstine LJ, Durando MM, Magdesian KG.Adiaspiromycosis is a fungal disease of the lung caused by the saprophytic soil mould Emmonsia crescens or, more rarely, E. p a rv a. The fungus affects lower order mammals, mostly rodents, and rarely man, although the organism is distributed worldwide (Sigler 1998). In veterinary medicine, the disease has been reported as an incidental histopathological finding in the lungs of one goat and 2 dogs (Al-Doory et al. 1971; Koller et al. 1976; Koller and Helfer 1978). The term adiaspiromycosis derives from the conidia of this fungus, the adiaconidia, which exhibit the unique property of progressiv...
Bertin FR, Ivester KM, Couëtil LL.Studies investigating the clinical efficacy of albuterol administered with the same propellant and commercially available delivery devices in horses with recurrent airway obstruction (RAO) are not currently available. Objective: To determine the efficacy of aerosolised albuterol administered to horses with RAO by means of 2 commercially available, hand-held delivery devices. Methods: Ten horses with RAO were kept in a dusty environment and fed mouldy hay to induce airway obstruction. Lung mechanics were measured before and after the procedure. ΔP(max) was measured 5 min after administration o...
Stack A, Derksen FJ, Williams KJ, Robinson NE, Jackson WF.Exercise-induced pulmonary hemorrhage is a performance-limiting condition of racehorses associated with severe pathology, including small pulmonary vein remodeling. Pathology is limited to caudodorsal (CD) lung. Mechanical properties of equine pulmonary microvasculature have not been studied. We hypothesized that regional differences in pulmonary artery and vein mechanical characteristics do not exist in control animals, and that racing and venous remodeling impact pulmonary vein mechanical properties in CD lung. Pulmonary arteries and veins [range of internal diameters 207-386 ± 67 μm (mean...
Nyman G, Marntell S, Edner A, Funkquist P, Morgan K, Hedenstierna G.Sedation with alpha2-agonists in the horse is reported to be accompanied by impairment of arterial oxygenation. The present study was undertaken to investigate pulmonary gas exchange using the Multiple Inert Gas Elimination Technique (MIGET), during sedation with the alpha2-agonist detomidine alone and in combination with the opioid butorphanol. Methods: Seven Standardbred trotter horses aged 3-7 years and weighing 380-520 kg, were studied. The protocol consisted of three consecutive measurements; in the unsedated horse, after intravenous administration of detomidine (0.02 mg/kg) and after sub...
Art T, Lekeux P.The exercise-induced changes in the equine breathing pattern were studied by analyzing tidal breathing flow-volume loops recorded in ten ponies both at rest and during a standardized exercise. Airflow, tidal volume, esophageal pressure and mask pressure were simultaneously recorded before, during and after a treadmill exercise. From the collected data, respiratory frequency and total pulmonary resistance were calculated, tidal breathing flow-volume loops were retraced using a computerized method and loop indices were measured for each period of the experimental protocol. For each pony, results...
Womble A, Giguère S, Murthy YV, Cox C, Obare E.The objectives of this study were to determine the serum and pulmonary disposition of tilmicosin in foals and to investigate the in vitro activity of the drug against Rhodococcus equi and other common bacterial pathogens of horses. A single dose of a new fatty acid salt formulation of tilmicosin (10 mg/kg of body weight) was administered to seven healthy 5- to 8-week-old foals by the intramuscular route. Concentrations of tilmicosin were measured in serum, lung tissue, pulmonary epithelial lining fluid (PELF), bronchoalveolar lavage (BAL) cells, and blood neutrophils. Mean peak tilmicosin conc...
Birks EK, Durando MM, McBride S.EIPH is a condition affecting virtually all horses during intense exercise worldwide. The hemorrhage originates from the pulmonary vasculature and is distributed predominantly bilaterally in the dorsocaudal lung lobes. As the condition progresses, the lung abnormalities extend cranially along the dorsal portions of the lung. An inflammatory response occurs in association with the hemorrhage and may contribute to the chronic sequela. Although conflicting opinions exist as to its affect on performance, it is a syndrome that is thought to increase in severity with age. The most commonly performed...
Schambourg MA, Laverty S, Mullim S, Fogarty UM, Halley J.Thoracic trauma occurs in newborn foals and may cause associated clinical signs; this condition remains poorly documented. Objective: The purpose of this study was to describe the pathological features of thoracic trauma in newborn foals presented for necropsy examination between 1990 and 2000. Methods: Necropsy reports of foals with thoracic trauma from 1990-2000 were reviewed. Subject details, clinical signs, thoracic and abdominal lesions were noted and analysed statistically. Results: Sixty-seven (9%) of 760 necropsied foals had thoracic trauma. In 19 foals, fractured ribs were considered ...
Winther L, Honoré Hansen S, Baptiste KE, Friis C.Doxycycline concentrations, following two types of oral administration to horses, in pulmonary epithelial lining fluid (PELF) were examined and compared to plasma concentrations. The oral bioavailability was estimated from plasma concentrations achieved after an intravenous study in two horses. Doxycycline (10 mg/kg) was administered either intragastric or as topdressing to nonfasted horses. Blood samples were collected for drug analysis, before and 11 times after administration during 24 h. PELF samples were collected by a tampon device four times after drug administration and analysed for do...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Lungs from 19 Thoroughbred racehorses with a history of exercise-induced pulmonary haemorrhage (EIPH) were studied using several forms of microscopy. Light microscopy of paraffin sections revealed three lesions in the caudodorsal region of the lungs from each horse. These correspond with the location of blue to brown stains seen at necropsy. These lesions include sequelae of bronchiolitis, hemosiderophages and increased connective tissue. Much of each of the lungs appeared normal, especially the more cranial or ventral portions. Foci of eosinophil infiltration were found in seven of the 19 lun...
McGorum BC, Dixon PM, Halliwell RE.Phenotypic analysis of lymphocytes in peripheral blood (PB) and bronchoalveolar lavage fluid (BALF) of control and chronic obstructive pulmonary disease (COPD) affected horses, both before and after 'natural (hay and straw) challenge', were performed using immunofluorescent labelling with monoclonal antibodies and flow cytometry. BALF lymphocytes were shown to be predominantly EqCD5+ cells, approximately half of which were also EqCD8+, with a smaller proportion of B cells. In comparison with PB, BALF contained higher proportions of EqCD5+ cells and EqCD8+ cells and a lower proportion of B cell...
Ammann VJ, Vrins AA, Lavoie JP.The effects of beclomethasone dipropionate on pulmonary function and arterial blood gas values were investigated in horses with chronic obstructive pulmonary disease (COPD). Six mature mares, diagnosed as having COPD based on clinical signs, cytological examination of bronchoalveolar lavage and pulmonary function testing, were used. Beclomethasone dipropionate (3750 microg) was administered b.i.d. for a 2 week period with a metered dose inhaler using a mask. Pulmonary function tests and arterial blood gas analyses were performed at weekly intervals, starting before beclomethasone administratio...
Derksen FJ, Robinson NE, Slocombe RF, Riebold TW, Brunson DB.Arterial blood gas tensions, pulmonary mechanics, and lung volumes were measured in 4 sedated ponies every hour for 6 hours and in 5 ponies 4 times at 2-month intervals to assess the short- and long-term reproducibility of pulmonary function measurements. Variability in blood gas tensions was small over the short- and long-term measurement periods, whereas the variability in total respiratory resistance and functional residual capacity was small over the short term but larger over the long term. The variability in tidal volume, minute ventilation, respiratory rate, and dynamic and quasistatic ...
Petsche VM, Derksen FJ, Robinson NE.Tidal breathing flow-volume (TBFV) loops were determined in a group of control horses and in horses affected with recurrent airway obstruction (heaves). The latter group was studied when the condition was in remission and under increasing amounts of airway obstruction as reflected by measurements of change in pleural pressure, pulmonary resistance, and dynamic compliance. The TBFV loops of control horses had biphasic inspiratory and expiratory patterns; peak inspiratory and peak expiratory flows were detected early in inspiration and expiration, respectively. Tidal volume was unaffected by hea...
Dixon CE, Bedenice D, Mazan MR.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 rand...
Dupont J, Serteyn D, Sandersen C.Horses are susceptible to developing large areas of pulmonary atelectasis during recumbency and anesthesia. The subsequent pulmonary shunt is responsible for significant impairment of oxygenation. Since ventilation perfusion mismatch persists into the post-operative period, hypoxemia remains an important concern in the recovery stall. This case report describes the diagnosis and supportive therapy of persistent hypoxemia in a 914 kg draft horse after isoflurane anesthesia. It highlights how challenging it can be to deal with hypoxemia after disconnection from the anesthesia machine and how lif...
Manohar M, Goetz TE.The present study was carried out to examine the effects of nitric oxide synthase inhibition with Nomega-nitro-L-arginine methyl ester (L-NAME) on the right atrial as well as on the pulmonary arterial, capillary, and venous blood pressures of horses during rest and exercise performed at maximal heart rate (HRmax). Experiments were carried out on seven healthy, sound, exercise-trained Thoroughbred horses. Using catheter-tip manometers, with signals referenced at the point of the shoulder, we determined phasic and mean right atrial and pulmonary vascular pressures in two sets of experiments [con...
Joubert P, Cordeau ME, Lavoie JP.Heaves in horses is characterized by lower airway neutrophilic inflammation, and reversible airflow obstruction. Pulmonary macrophages contribute to the inflammation observed in a number of human and animal pulmonary diseases, and it has been postulated that they are responsible for the neutrophilic inflammation present in heaves by the release of cytokines and chemokines. To test this hypothesis, the mRNA expression of TNF-α, IL-1β, IL-8, and MIP-2 by macrophages isolated from bronchoalveolar lavage cells was quantified using real-time RT-PCR in horses with heaves (n-6) and controls (n-6). ...
Sinclair SE, McKinney S, Glenny RW, Bernard SL, Hlastala MP.We determined the changes in fractal dimensions and spatial correlations of regional pulmonary blood flow with increasing exercise in race horses (n = 4) by using 15-microm fluorescent microspheres. Fluorescence was measured to quantitate regional blood to 1.3-cm(3) samples (n = 1,621-2,503). Perfusion distributions were characterized with fractal dimensions (a measure of spatial variability) and spatial correlations. On average, the fractal dimension decreased with exercise (trot 1.216 to gallop 1.173; P < 0. 05) despite a variable fractal dimension at rest. Spatial correlation of flow to ...
Hobo S, Oikawa M, Kuwano A, Yoshida K, Yoshihara T.To study the effects of extended transportation on the composition of bronchoalveolar lavage fluid (BALF) obtained from horses. Methods: 30 horses (14 males, 16 females: 25 Thoroughbreds and 5 Thoroughbred-Arabian cross-breds; 27 to 30 months old) without a history or clinical signs of respiratory tract disease. Bronchoalveolar lavage was performed on nontransported control horses (groups 1 and 2) and transported horses (group 3). Methods: 20 horses were used to determine the effect of 41 hours of transportation on the composition of BALF (group 3). Bronchoalveolar lavage fluid was analyzed fo...
Aharonson-Raz K, Singh B.Endotoxemia causes significant mortality and morbidity in horses. The mechanisms underlying this complex pathophysiology remain unclear. Therefore, effective tools to treat endotoxemia in horses are lacking. Furthermore, the multifactorial and multiorgan pathophysiology of equine endotoxemia has not been fully addressed, especially the lung injury associated with endotoxemia. Within the context of the broader picture of endotoxemia and lung injury, we offer a perspective on the roles of pulmonary intravascular macrophages in endotoxin-induced lung inflammation in horses. L’endotoxémie est u...
van den Hoven R, Zappe H, Zitterl-Eglseer K, Jugl M, Franz C.The effects of an oral preparation containing an extract of thyme and primula (Bronchipret; Bionorica) on the lung function of five horses suffering heaves were determined in a longitudinal study. The horses accepted the product well. The plasma concentrations of the marker substance, thymol, indicated that at least one of the substances in the extract had been absorbed from the gastrointestinal tract. The compliance, pulmonary pressure and airway resistance of the horses' lungs were all significantly improved after one month of treatment However, the severity of their clinical signs and their...
Rush BR, Flaminio MJ, Matson CJ, Hakala JE, Shuman W.To determine cytologic changes in horses with recurrent airway obstruction (heaves) after administration of aerosolized beclomethasone dipropionate and dexamethasone parenterally. Methods: 6 horses with inducible and reversible heaves. Methods: Episodes of heaves were induced by exposure to moldy hay and straw for 7 days. Horses were assigned to treatment groups (aerosolized beclomethasone, parenterally administered dexamethasone, aerosolized propellant), and pulmonary inflammation was evaluated by serial cytologic examination of bronchoalveolar lavage (BAL) fluid samples obtained on days 0, 7...
Winther L, Baptiste KE, Friis C.Cefquinome concentrations, following intravenous and aerosol administration to horses, in pulmonary epithelial lining fluid (PELF) were examined and compared to plasma concentrations. Single dose of cefquinome sulphate (1 mg/kg) was administered intravenously to six horses followed by a single aerosol administration (225 mg) with a wash-out period of 14 days between treatments. After each drug administration, cefquinome concentrations in plasma and PELF, obtained by intrabronchial cotton swabs, were determined. After intravenous administration, cefquinome concentrations in plasma declined fast...
