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.
Javsicas LH, Giguère S, Womble AY.The objectives of this study were to determine the serum and pulmonary disposition of telithromycin in foals and to determine the minimum inhibitory concentration (MIC) of telithromycin against macrolide-susceptible and macrolide-resistant Rhodococcus equi isolates. A single dose of telithromycin (15 mg/kg of body weight) was administered to six healthy 6-10-week-old foals by the intragastric route. Activity of telithromycin was measured in serum, pulmonary epithelial lining fluid (PELF), and bronchoalveolar lavage (BAL) cells using a microbiological assay. The broth macrodilution method was u...
Marcilla MG, Schauvliege S, Duchateau L, Gasthuys F.To evaluate the cardiopulmonary effects of two different constant rate infusions (CRI) of dexmedetomidine (1 and 1.75 microg kg(-1 )hour(-1)) in experimental ponies. Methods: Six healthy ponies (mean 306 +/- SD 71 kg, 7.0 +/- 1.6 years). Methods: Prospective, randomized, experimental study. Methods: After premedication with intravenous (IV) dexmedetomidine (3.5 microg kg(-1)), anaesthesia was induced (T0) with ketamine (2.2 mg kg(-1) IV) and midazolam (0.06 mg kg(-1) IV) and maintained with isoflurane (Fe'ISO 1.50%) in 55% oxygen for 150 minutes. Normocapnia was maintained using artificial ven...
Leclere M, Lefebvre-Lavoie J, Beauchamp G, Lavoie JP.Orally administered prednisolone and dexamethasone are used commonly in the treatment of recurrent airway obstruction (RAO) in horses. However, the efficacy of prednisolone in improving pulmonary function during continuous antigen exposure has not been evaluated critically and there is little evidence supporting the efficacy of low-dose oral dexamethasone in the same conditions. Objective: Oral prednisolone and dexamethasone improve pulmonary function in RAO under conditions of continuous antigen exposure, and dexamethasone is more effective than prednisolone at commonly used dosages. Methods:...
Oslund KL, Adamson G, Wu R.To isolate and culture primary equine airway epithelial cells in vitro and elucidate the major cytokines involved in expression of the gel-forming mucin gene MUC5AC in horses. Methods: 12 tracheas obtained within 5 hours after euthanasia from horses free from respiratory tract disease. Methods: Tracheal rings were digested overnight in 0.2% protease, and dissociated airway epithelial cells were grown in a serum-free defined medium at an air-liquid interface until confluence was achieved. Differentiated airway epithelial cells were treated with a panel of recombinant equine cytokines followed b...
Beeler-Marfisi J, Clark ME, Wen X, Sears W, Huber L, Ackerley C, Viel L, Bienzle D.To evaluate experimental induction of recurrent airway obstruction (RAO) with inhaled fungal spores, lipopolysaccharide, and silica microspheres in horses. Methods: 7 horses with and 3 horses without a history of RAO. Methods: RAO-susceptible horses ranged in age from 17 to approximately 30 years, and control horses ranged in age from 7 to approximately 15 years. Pure mold cultures were derived from repeated culture of hay and identified via gene amplification and sequencing. Pulmonary function testing and bronchoalveolar lavage were performed before and after nebulization with a suspension of...
Saulez MN, Godfroid J, Bosman A, Stiltner JL, Breathnach CC, Horohov DW.To determine concentrations of cytokine mRNA in horses with exercise-induced pulmonary hemorrhage (EIPH) after racing. Methods: 97 Thoroughbreds. Methods: Following tracheobronchoscopy, the severity of EIPH was graded (scale of 0 to 4), and venous blood samples were collected from 10 horses in each grade. After RNA isolation and cDNA synthesis, real-time PCR assay was conducted to detect cytokinespecific mRNA for interleukin (IL)-1, IL-6, and IL-10; interferon (INF)-gamma; and tumor necrosis factor (TNF)-alpha. Results: Neither location nor grade of EIPH affected the expression of IL-1 and INF...
Venugopal CS, Mendes LC, Peiró JR, Laborde SS, Stokes AM, Moore RM.To identify differentially expressed genes in pulmonary tissues of horses affected with summer pasture-associated obstructive pulmonary disease (SPAOPD), which is a form of recurrent airway obstruction (RAO), compared with those of unaffected horses. Methods: 6 horses with SPAOPD-RAO and 6 unaffected (healthy) horses. Methods: Horses were assigned to 2 groups on the basis of medical history, clinical score, and transpleural pressure. Total RNA from each of the 5 lung lobes of each of the 6 SPAOPD-RAO-affected horses was extracted and pooled. Similarly, total RNA from unaffected horses was pool...
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...
Kaartinen MJ, Pang DS, Cuvelliez SG.CASE 1: A two-year old, 462 kg Standard bred horse was anesthetized for arthroscopy and castration. During anesthesia, hyperemia of the mucosal membranes and urticaria were noticed. During 5 hours of anesthesia subcutaneous edema of the eyelids and neck region developed. In the recovery box, the orotracheal (OT) tube was left in situ and secured in place with tape. Following initial attempts to stand, the horse became highly agitated and signs consistent with pulmonary edema developed subsequently. Arterial hypoxemia (PaO(2): 3.7 kPa [28 mmHg]) and hypocapnia (PaCO(2): 3.1 kPa [23 mmHg]) were ...
Teeter MG, Arroyo LG, Bakker JD, Hayes MA, Viel L, Runciman RJ.Arterial calcification is found frequently in the pulmonary artery of racehorses, but the aetiology is unknown. Calcification might be associated with increased wall stress due to arterial geometry (shape) and exercise-induced hypertension. Objective: High wall stress levels are found in the regions associated with calcified lesion formation, exacerbated as transluminal pressure increases to levels associated with exercise. Methods: The pulmonary arteries of 5 horses, unaffected by calcification, were dissected and pressurised to resting and exercising physiological transluminal pressures and ...
Staffieri F, Bauquier SH, Moate PJ, Driessen B.It is unknown whether administration of gas-mixtures high in inspired fraction of oxygen (FiO2) under general anaesthesia may increase formation of pulmonary atelectasis and impair gas exchange. Objective: To evaluate the effects of different FiO2 on pulmonary gas exchange in isoflurane-anaesthetised horses breathing a helium/oxygen (He/O2) mixture. Methods: Thirty healthy mature horses were sedated with i.v. acepromazine (0.02 mg/kg bwt), detomidine (0.002 mg/kg bwt) and xylazine (02-0.4 mg/kg bwt). General anaesthesia was induced with i.v. 5% guaifenesin to effect, diazepam (0.1 mg/kg bwt) a...
Kutasi O, Horvath A, Harnos A, Szenci O.We characterized the kinetics of postnatal equine lung using sequential thoracic radiography. The aim was to establish the earliest time when normal foals have clear, radiolucent lung fields, and to characterize the pattern of this clearance. Both right-to-left and left-to-right thoracic radiographs were acquired in lateral recumbency at peak inspiration within the first 30 min after birth and thereafter at 1, 2, 3, 4, 6, 8, 12, 24, 48, and 72 h. Radiographs were interpreted by three observers. The overall assessment of radiographic lung clearance was followed by the evaluation of individual l...
Reyner CL, Wagner B, Young JC, Ainsworth DM.To examine gene expression of selected cytokines in pulmonary mononuclear cells isolated from healthy horses and horses susceptible to recurrent airway obstruction (RAO), and to determine whether interleukin (IL)-17 and IL-23 were associated with pulmonary inflammation. Methods: 6 RAO-susceptible and 5 healthy horses. Methods: Bronchoalveolar lavage cells were retrieved from horses that were stabled and fed dusty hay for 24 hours. Lavage cells devoid of neutrophils were incubated for 24 hours with solutions of PBS, hay dust, lipopolysaccharide, or B-glucan. Gene expression of IL-17, IL-23 (p19...
Costa LR, Eades SC, Venugopal CS, Moore RM.Summer pasture-associated recurrent airway obstruction (SPA-RAO), a seasonal airway obstructive disease of horses, is characterized by clinical exacerbation after exposure to pasture during warm months of the year. Endothelin (ET)-1, potent bronchoconstrictor, mitogen, secretagogue, and proinflammatory mediator, has been implicated in the pathogenesis of asthma and equine heaves. Objective: Immunoreactive ET-1 concentrations increase during clinical exacerbation and return to basal values during periods of disease remission. Methods: Twelve horses, 6 affected with SPA-RAO and 6 nonaffected. Me...
Christmann U, Hite RD, Witonsky SG, Elvinger F, Werre SR, Thatcher CD, Tan RH, Buechner-Maxwell VA.Surfactant alterations are described in horses after exercise, anesthesia, and prolonged transport, in horses with recurrent airway obstruction, and in neonatal foals. The effect of horse age or bronchoalveolar lavage fluid (BALF) sample characteristics on surfactant is unknown. Objective: To evaluate surfactant phospholipid composition and function in healthy horses, and to investigate the influence of age and BALF sample characteristics on surfactant. Methods: Seventeen healthy horses 6-25 years of age maintained on pasture year-round. Methods: BALF was collected by standard procedures and w...
Hinchcliff KW, Morley PS, Guthrie AJ.To evaluate the efficacy of furosemide for prevention of exercise-induced pulmonary hemorrhage (EIPH) in Thoroughbred racehorses under typical racing conditions. Methods: Randomized, placebo-controlled, blinded, crossover field trial. Methods: 167 Thoroughbred racehorses. Methods: Horses were allocated to race fields of 9 to 16 horses each and raced twice, 1 week apart, with each of the 2 races consisting of the same race field and distance. Each horse received furosemide (500 mg, IV) before one race and a placebo (saline solution) before the other, with the order of treatments randomly determ...
Richard EA, Fortier GD, Denoix JM, Art T, Lekeux PM, Van Erck E.Inflammatory airway disease (IAD) is a nonseptic condition of the lower respiratory tract. Its negative impact on respiratory function has previously been described using either forced expiration or forced oscillations techniques. However, sedation or drug-induced bronchoconstriction were usually required. The impulse oscillometry system (IOS) is a noninvasive and sensitive respiratory function test validated in horses, which could be useful to evaluate IAD-affected horses without further procedures. Objective: To determine the sensitivity of IOS in detecting alterations of the respiratory fun...
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...
von Bargen K, Haas A.The soil actinomycete Rhodococcus equi is a pulmonary pathogen of young horses and AIDS patients. As a facultative intracellular bacterium, R. equi survives and multiplies in macrophages and establishes its specific niche inside the host cell. Recent research into chromosomal virulence factors and into the role of virulence plasmids in infection and host tropism has presented novel aspects of R. equi infection biology and pathogenicity. This review will focus on new findings in R. equi biology, the trafficking of R. equi-containing vacuoles inside host cells, factors involved in virulence and ...
Venugopal CS, Holmes EP, Polikepahad S, Laborde S, Kearney M, Moore RM.The purpose of the study was to compare in vitro airway responses to neurokinin A & B (NKA and NKB) and expression of NK-2 receptors in airways of horses affected and unaffected with recurrent airway obstruction (RAO). Neurokinin-A, an inflammatory mediator belonging to the tachykinin family of neuropeptides, causes bronchoconstriction by binding to NK-2 receptors. Neurokinin-B is a lesser-known neuropeptide that acts on NK-3 receptors. Horses were placed into RAO-affected and RAO-unaffected groups based on their history, clinical scoring, and pulmonary function testing. Lung tissue from e...
Vannella KM, Moore BB.Idiopathic pulmonary fibrosis (IPF) remains exactly that. The disease originates from an unknown cause, and little is known about the mechanisms of pathogenesis. While the disease is likely multi-factorial, evidence is accumulating to implicate viruses as co-factors (either as initiating or exacerbating agents) of fibrotic lung disease. This review summarizes the available clinical and experimental observations that form the basis for the hypothesis that viral infections may augment fibrotic responses. We review the data suggesting a link between hepatitis C virus, adenovirus, human cytomegalo...
Arroyo LG, Hayes MA, Delay J, Rao C, Duncan B, Viel L.Calcification of large arteries has been sporadically reported in horses. The pathogenesis is still unknown, but recent studies in humans suggest that this is a regulated biomineralizing process. This study surveyed the prevalence, distribution, and severity of vascular calcification in Thoroughbred and Standardbred racehorses. Histopathologic, ultrastructural imaging, and energy dispersive X-ray elemental analyses were used to examine the lesions. Calcification of the tunica media, predominantly the pulmonary artery, was found in 82% of horses (83/101). Young adult horses (mean [SD] age in ye...
Menzies-Gow NJ.Eight normal thoroughbred horses were examined by echocardiography before and 10 minutes after they had been sedated by the intravenous administration of 0.03 mg/kg acepromazine. There were significant (P<0.025) increases in the diameters of the pulmonary artery and the aorta, measured at end-systole, and in the thickness of the interventricular septum, measured at end-systole and end-diastole. In addition, there was a significant (P<0.001) decrease in the diameter of the left atrium measured at end-diastole. The remaining cardiac dimensions, all the indices of cardiac function, and the ...
Bedenice D, Mazan MR, Hoffman AM.The objective of this study was to examine the relationship between chronic cough, pulmonary mechanical function, bronchial hyper-responsiveness, and peripheral airway inflammation in adult performance horses with nonseptic inflammatory airway disease (IAD). Objective: We hypothesized that horses with a presenting complaint of cough have a higher percentage of inflammatory cells on bronchoalveolar lavage (BAL), greater airway obstruction, and airway hyper-responsiveness (AHR) than do horses without cough. ANIMALS/SAMPLE POPULATION: Adult performance horses (n = 137) referred for evaluation of ...
Gehlen H, Oey L, Rohn K, Bilzer T, Stadler P.Chronic pulmonary diseases (recurrent airway obstruction [RAO]) have been reported to alter skeletal muscle cells in humans. The purpose of this study was to evaluate a potential relationship between pulmonary and muscle variables in horses with a clinical diagnosis of RAO. Muscle biopsies from healthy horses and from horses with RAO were investigated and the relationship between the severity of lung disease and the degree of muscular changes was determined. Objective: We hypothesized that chronic pulmonary disease can lead to changes of the skeletal muscle in horses. Methods: Fifteen healthy ...
Cunningham FM, Dunkel B.Recurrent airway obstruction (RAO) and insect bite hypersensitivity (IBH) are allergic conditions that are commonly encountered in the horse. Whilst complete allergen avoidance is an effective management strategy for both diseases, this may not be achievable in all cases and treatment options are therefore required. The inflammatory response is the main therapeutic target for glucocorticoids given to horses with RAO and severe cases of IBH, whilst the bronchodilators used in RAO primarily target airway smooth muscle. Such drugs are effective in most but not all individuals and there may be unw...
Schatzmann U, Koehli M, Dudan F, Rohr W, Jones RS.Certain circulatory and respiratory values were measured in horses in the standing, lateral, and supine positions. Twelve adult horses were kept in the standing position under the influence of glycerol guiacolate. Alterations in position to lateral and dorsal recumbencies were achieved without any further drug administration. The changes from the standing to the lateral position decreased the arterial oxygen tension, but left the arterial carbon dioxide tension unchanged. There was no statistically significant effect of body position on respiratory flow rates or volumes. The shift from the lat...
Ducharme NG, Hackett RP, Gleed RD, Ainsworth DM, Erb HN, Mitchell LM, Soderholm LV.We hypothesized that changes in pleural pressure induced by resistive breathing would affect transmural pulmonary artery, pulmonary capillary, and pulmonary wedge pressures. Seven horses were assigned to exercise with each of 4 upper respiratory resistive loads in random order at intervals of at least 2 days: 1) control--no added resistive loads; 2) inspiratory resistive load (Iobst)--left laryngeal hemiplegia; 3) expiratory resistive load (Eobst)--one-way valve in the right nostril; and 4) combined inspiratory and expiratory resistive loads (CIEobst)--left nostril occlusion. On each occasion,...
Kindig CA, McDonough P, Fenton G, Poole DC, Erickson HH.The purpose of this investigation was to study the effects of an equine nasal strip (NS), furosemide (Fur), and a combination of both (NS + Fur) on exercise-induced pulmonary hemorrhage (EIPH) at speeds corresponding to near-maximal effort. Five Thoroughbreds (526 +/- 25 kg) were run on a flat treadmill from 7 to 14 m/s in 1 m x s(-1) x min(-)1 increments every 2 wk (treatment order randomized) under control (Con), Fur (1 mg/kg iv 4 h prior), NS, or NS + Fur conditions. During each run, pulmonary arterial (Ppa) and esophageal (Pes) pressures were measured. Severity of EIPH was quantified via b...
Léguillette R, Lavoie JP.To evaluate whether bronchoalveolar lavage (BAL) alters respiratory mechanics of horses with recurrent airway obstruction (ie, heaves) over a 48-hour period. Methods: 6 horses affected with heaves. Methods: Horses were subjected to a complete BAL procedure, which included sedation with xylazine and butorphanol, intratracheal administration of lidocaine, and instillation and aspiration of two 250-mL boluses of saline (0.9% NaCl) solution through an endoscope (study 1). To evaluate the effects of saline solution, horses were subjected to the same procedure without saline solution instillation an...
Crichlow EC, Yoshida K, Wallace K.Over a period of 4 months, in winter, the mean concentration of airborne particles in the ambient air of a riding stable was 0.41 mg/m3. This value was significantly higher than that found outdoors (0.04 mg/m3). During the day, levels of airborne particles were highest when stalls were cleaned and soiled bedding from the previous night replenished, and lowest when all stable activities had ceased. Fine particles, capable of entering the pulmonary alveoli, constituted 30 to 40 per cent of the total mass concentration of airborne particles.
Burnheim K, Hughes KJ, Evans DL, Raidal SL.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 c...
Crispe EJ, Lester GD.Exercise-induced pulmonary hemorrhage (EIPH) occurs commonly in horses undergoing strenuous exercise. Reported risk factors include racing in cold temperatures and wearing of bar shoes. In horses with documented moderate to severe EIPH, increasing the interval between races and adopting a negative race pace strategy may reduce the severity of EIPH in subsequent races. EIPH seems to have an impact on performance only when moderate to severe. This occurs in a small number of starters, approximately 6%. EIPH often is erratic in severity from race to race, although across a population it is weakly...
Oikawa M.The dorsocaudal extremities of the caudal lobes of the lungs of racehorses are vulnerable to exercise-induced pulmonary haemorrhage (EIPH). The morphology of the lungs at these sites was studied in 13 Thoroughbred horses aged 18 to 22 months. These animals, which had been performing low-intensity exercise on a track at maximum running speeds of approximately 5-8.5 metres/second (m/s), were withdrawn from the racehorse training programme for reasons of unsuitability. Lung lesions observed in the dorsocaudal lung extremities in 10 of the 13 horses were not found in the craniodorsal or craniovent...
Staffieri F, Bauquier SH, Moate PJ, Driessen B.It is unknown whether administration of gas-mixtures high in inspired fraction of oxygen (FiO2) under general anaesthesia may increase formation of pulmonary atelectasis and impair gas exchange. Objective: To evaluate the effects of different FiO2 on pulmonary gas exchange in isoflurane-anaesthetised horses breathing a helium/oxygen (He/O2) mixture. Methods: Thirty healthy mature horses were sedated with i.v. acepromazine (0.02 mg/kg bwt), detomidine (0.002 mg/kg bwt) and xylazine (02-0.4 mg/kg bwt). General anaesthesia was induced with i.v. 5% guaifenesin to effect, diazepam (0.1 mg/kg bwt) a...
Gallivan GJ, McDonell WN, Forrest JB.Pulmonary mechanics and lung volumes were measured in horses and cows to determine if differences in breathing pattern between the two species were due to differences in the mechanical properties of the lungs. Tidal volume (VT) was larger in the horses, while the respiratory rate (fR) and minute ventilation (VE) were higher in the cows. The horses often had a double peak in airflow during inspiration and, or, expiration, while the cows had a single peak during expiration. Measured lung volumes were larger in the horses and they had a higher dynamic lung compliance (Cdyn,L), although the static...
Bernard SL, Glenny RW, Erickson HH, Fedde MR, Polissar N, Basaraba RJ, Hlastala MP.We determined the spatial distribution of pulmonary blood flow at rest and during increasing levels of exercise (34, 59, and 90% of maximal oxygen consumption) in Thoroughbred racehorses (n = 4) using 15-microns fluorescent microspheres. After the horses were killed, the lungs were flushed free of blood, removed, air-dried at total lung capacity, and sliced into isogravitational planes, which were sampled in a systematic fashion for three-dimensional reconstruction. The fluorescence was measured for quantification of blood flow. Mean pulmonary blood flow heterogeneity (expressed as a coefficie...
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...
Marntell S, Nyman G.The clinical and cardiorespiratory effects of premedication with acepromazine, butorphanol or diazepam in addition to romifidine before induction of anaesthesia with ketamine were studied in 6 horses on 4 random occasions. Administration of romifidine alone or in combination with butorphanol resulted in an increase in arterial blood pressure, accompanied by a significant decrease in heart rate with second-degree atrio-ventricular heart block. Induction of anaesthesia with ketamine returned the heart rate to baseline value, but the arterial blood pressure was significantly increased compared to...
Kohn CW, Hinchcliff KW, McKeever KH.To determine whether body temperature of horses exercised in hot, humid conditions and then repetitively washed with cold water will decrease more rapidly than that of horses that are not washed, and to determine whether washing with cold water has deleterious effects on horses. Methods: 5 physically fit Thoroughbred mares, 3 to 10 years old. Methods: Horses were exercised on a high-speed treadmill in hot (31.1+/-0.3 C), humid (relative humidity, 77.7+/-2%) conditions. Exercise was terminated when pulmonary artery temperature reached 41.5 C. Values for pulmonary artery, rectal, and left glutea...
Benamou AE, Art T, Marlin DJ, Roberts CA, Lekeux P.Recurrent airway obstruction (RAO) is an asthma-like condition of the horse that represents a major cause of morbidity and loss of performance. The exact pathogenesis of asthma in man is unclear but the role of endothelin (ET) is currently under investigation, thus sparking interest in the bronchoconstrictive and vasoconstrictive properties of endothelin in the equine-specific disease entity. In this study, we investigated the levels of ET-1 in systemic blood, as well as in bronchoalveolar lavage (BAL) from horses with RAO. We also studied how these values might correlate with those of lung fu...
Gasthuys F, de Moor A, Parmentier D.The effects of change in position and respiration modes were studied in 5 experimental ponies during a standard halothane anaesthesia. A marked cardiovascular depression (decrease in mean arterial blood pressure, cardiac output, stroke volume and left ventricle work) occurred in recumbent, spontaneously breathing ponies. No significant differences were found between right and left lateral recumbency. The most pronounced cardiovascular depression was observed in the dorsal position. Sternal recumbency appeared to be slightly beneficial (higher systemic blood pressure and arterial oxygenation). ...
Amis TC, Pascoe JR, Hornof W.The regional distribution of ventilation to perfusion ratios (VA/Q) in the lungs of 8 healthy standing Thoroughbred geldings (4.4 +/- 1.5 years, 465.7 +/- 46.6 kg) was studied, using steady-state inhalation and IV infusion of the radioactive gas krypton-81m. The VA/Q was uniformly distributed within a vertical lung strip centered over the 9th rib on the right side. Ventilation per unit of alveolar volume (V/VA) assessed from the clearance of inhaled radioactive gas in 5 horses increased from 0.49 +/- 0.13 (arbitrary units) in nondependent lung zones to 1.45 +/- 0.16 in dependent lung zones. Se...
Olson LE, Lai-Fook SJ.Pleural liquid pressure was measured at end expiration in 11 spontaneously breathing anesthetized ponies in the prone and supine positions. A liquid-filled capsule was implanted into a rib to measure pleural liquid pressure with minimal distortion of the pleural space (Wiener-Kronish et al., J. Appl. Physiol. 59: 597-602, 1985). Capsule position relative to lung height was measured from thoracic radiographs taken in each position. In each body position, pleural liquid pressure was most negative in the superior lung regions and least negative in the inferior lung regions. In the supine position...
Voynick BT, Sweeney CR.Philippine polo and racing horses were examined for exercise-induced pulmonary hemorrhage after their competitive exercise. Exercise-induced pulmonary hemorrhage occurred in 11.1% of the polo horses and 64% of the racing horses. None of the horses had blood at the nostrils.
Sweeney CR, Habecker PL.To analyze medical records and identify factors that veterinarians can use to prevent pulmonary aspergillosis in horses or that would enable them to diagnose it as early as possible. Methods: Retrospective study. Methods: 29 horses. Methods: Medical records were reviewed for horses with pulmonary aspergillosis diagnosed on the basis of characteristic postmortem findings. Information on history, clinical signs, disease progression, and postmortem findings was obtained. Results: 25 of 29 (86.2%) horses had primary (n = 20) or secondary (5) disease compatible with loss of integrity of the gastroi...
Johnson PJ, Moore LA, Mrad DR, Turk JR, Wilson DA.The sudden death of two horses was attributed to the rapid and acute development of pulmonary aspergillosis. One horse was making excellent postoperative progress after a jejunal resection and anastomosis for intestinal adhesions. The other horse was being treated routinely for equine protozoal myeloencephalitis (EPM). Signs of fever and an increased respiratory rate were detected shortly before death in the first horse, but no premonitory clinical signs characteristic of pulmonary infection were detected in the horse being treated for EPM. Both horses developed rapidly debilitating, acute pul...
Mosing M, MacFarlane P, Bardell D, Lüthi L, Cripps PJ, Bettschart-Wolfensberger R.To evaluate the effects of continuous positive airway pressure (CPAP) on intrapulmonary shunt, cardiac output and oxygen delivery in horses subjected to a 6 hour period of general anaesthesia. Methods: Randomized, experimental, crossover study. Methods: Ten healthy adult horses. Methods: Following medetomidine, diazepam and ketamine administration, orotracheal intubation was performed and horses positioned in dorsal recumbency. Anaesthesia was maintained with isoflurane carried in an oxygen and air mix (FiO 0.5) combined with a medetomidine infusion. Horses were anaesthetized twice and either...
Villarino N, Martín-Jiménez T.Macrolides are used for treatment of pneumonia and extrapulmonary conditions caused by Rhodococcus equi. In foals, macrolides have an extraordinary capacity to accumulate in different lung tissue compartments. These drugs show unique pharmacokinetic features such as rapid and extensive distribution and long persistence in pulmonary epithelial lining fluid (PELF) and bronchoalveolar lavage (BAL) cells from foals. This article reviews the pharmacokinetic characteristics of erythromycin, azithromycin, clarithromycin, tulathromycin, telithromycin, gamithromycin, and tilmicosin in foals, with empha...
Halliwell RE, Fleischman JB, Mackay-Smith M, Beech J, Gunson DE.Twenty-five horses with chronic pulmonary disease were skin tested with allergenic extracts of 24 molds, 4 thermophilic actinomyces, barn dust, hay dust, soya-bean mill dust, and grain mill dust. The results were compared with those obtained on 25 normal horses. Between the 2 groups of horses, there was a highly significant difference in positive skin test results at 30 minutes and 4 hours.
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...
