Exercise-Induced Pulmonary Hemorrhage (EIPH) is a condition observed in horses, characterized by bleeding from the blood vessels within the lungs during or shortly after intense physical activity. This phenomenon is commonly identified in racing and performance horses. The condition is associated with the rupture of pulmonary capillaries, leading to the presence of blood in the airways. EIPH can affect a horse's respiratory efficiency and overall performance. Diagnosis is typically confirmed through endoscopic examination or detection of blood in the trachea post-exercise. This page compiles peer-reviewed research studies and scholarly articles that explore the pathophysiology, diagnosis, management, and implications of EIPH in equine athletes.
Sweeney CR, Hall J, Fisher JR, Leary HJ, Soma LR, Spencer PA.The efficacy of water vapor-saturated air as a treatment for horses with exercise-induced pulmonary hemorrhage (EIPH) was studied. Horses selected for study (n = 14) had grade 1 or greater hemorrhage in the trachea after a minimum of 4 breezes between 0.8 and 1 km, as determined by endoscopy. Nine horses were treated with water vapor-saturated air; 5 horses were not treated. When the mean and maximal EIPH scores from the pretreatment period were compared with the mean and maximal EIPH scores from the treatment period in both treated and nontreated groups, there was no significant difference be...
Gunson DE, Sweeney CR, Soma LR.Pathologic changes are described in 11 horses that died during racing or training; 9 died of acute pulmonary hemorrhage (exercise-induced pulmonary hemorrhage), 1 died of exsanguination, and 1 died of CNS trauma. Cardiac lesions were not found in any horse. Severe engorgement of pulmonary vessels, with hemorrhage into alveoli, airways, interstitium, and subpleural tissues, was observed in all 9 horses that died of exercise-induced pulmonary hemorrhage. Infiltration of eosinophils and/or lymphocytes around vessels and airways was seen in 6 horses. Focally extensive fibrosis was observed in the ...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.The purpose of this study was to use radiographic contrast techniques and special imaging methods to identify and high-light bronchial arterial involvement in lung lesions associated with exercise-induced pulmonary haemorrhage (EIPH) in horses. The lungs from four horses with histories of EIPH were prepared for computerised tomographic scanning and microradiography by perfusing the broncho-oesophageal artery with a mixture of red latex and either barium or iodine contrast materials while the pulmonary supply received only blue latex. Computerised tomographic scan slices of the prepared inflate...
O'Callaghan MW, Hornof WJ, Fisher PE, Pascoe JR.Detailed post mortem examination of the lungs of horses with exercise-induced pulmonary haemorrhage (EIPH) has demonstrated significant small airway disease and intense bronchial arterial proliferation in the dorsocaudal lungfields. The purpose of this study was to investigate ventilation and perfusion distribution in the lungs of a similar group of horses to compare changes in the live animal with the previously reported post mortem findings. Thoracic radiography and ventilation/perfusion (V/Q) scintigraphy were performed on five racing Thoroughbreds with recent histories of EIPH. Parametric ...
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...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.This paper reviews a series of clinical, post mortem and imaging studies on exercise-induced pulmonary haemorrhage (EIPH) performed on 26 Thoroughbred racehorses. Post mortem techniques included routine gross, subgross and histological examination; coloured latex perfusions of pulmonary and bronchial circulations; and microradiography and computerised tomography scans of lungs with contrast injected vasculature. The major lesions were multiple, separate and coalescing foci of moderately proliferative small airway disease accompanied by intense neovascularisation of the bronchial circulation. A...
O'Callaghan MW, Pascoe JR, O'Brien TR, Hornof WJ, Mason DK.This study was initiated to determine if the extent and intensity of lung lesions associated with exercise-induced pulmonary haemorrhage (EIPH) in horses could be predicted from thoracic radiographs. Sets of thoracic radiographs from 24 horses with varied histories of EIPH were subjectively coded for radiographic quality, and perceived extent and intensity of diffuse interstitial opacity by three radiologists who had no knowledge of the corresponding autopsy results. Codes assigned from radiographs for the chosen parameters were compared with coded estimates of lung surface staining assigned a...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Latex was injected under pressure into bronchial and pulmonary arteries of the inflated lungs of Thoroughbreds and transverse sections taken to calculate the area of lesions resulting from exercise-induced pulmonary haemorrhage. Extensive areas of dense brown haemosiderin varying from 0 to 45 per cent of total lung volume were identified, predominantly in the dorsocaudal lungfields. Bronchial arterial proliferation appeared to have replaced the pulmonary supply in affected areas of the lung. Closely associated with the staining and bronchial arterialisation, there was widespread small airway d...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Detailed physical and clinical examinations were performed on 26 Thoroughbred racehorses which were used subsequently in a series of studies to investigate the contribution of the pulmonary and bronchial arterial circulations to the pathophysiology of exercise-induced pulmonary haemorrhage (EIPH). Twenty-five of the horses had been retired from race training in Hong Kong during the 1984-85 season, all but four raced that season; one horse had been retired the previous season. The average number of races for the group that season was 4.1 +/- 2 with an average distance of 1502 +/- 216 metres, me...
O'Callaghan MW, Pascoe JR, Tyler WS, Mason DK.Gross post mortem examinations were performed on the lungs of 26 Thoroughbred horses of known exercise-induced pulmonary haemorrhage (EIPH) status. The most consistent finding was a variable degree of bilaterally symmetrical, dark discolouration of the dorsocaudal regions of the caudal lung lobes. In more severely affected lungs, the stained areas extended cranially along the dorsal surfaces of the lungs, and in some cases affected approximately one third of the lung surface. Discoloured areas of lung were denser than normal, collapsed less readily, often contained trapped air and were slow to...
Hillidge CJ, Whitlock TW.Post race endoscopy was carried out on 255 two-year-old quarter horses and exercise-induced pulmonary haemorrhage (EIPH) was diagnosed in 166 (65 per cent) of them. Visible epistaxis was seen in a higher proportion of geldings than in either mares or stallions. The prevalence of EIPH was similar in mares (73 per cent) and in geldings (74 per cent). A significantly lower prevalence (49 per cent) was noted in stallions (P less than 0.01). It was concluded that a sex variation in the prevalence of EIPH exists in two-year-old quarter horses.
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.
Bove AA.Myocardial blood flow is the major determinant of oxygen delivery to the myocardium, since oxygen extraction by the myocardium is near maximum in the resting state. Regulation of flow during exercise depends on local metabolic factors and, to a small extent, on autonomic tone. Maximum flow of 5-6 times resting has been measured in reactive hyperemia experiments. In strenuous exercise, myocardial oxygen delivery appears to be adequate and flow reserve seems capable of handling the increased oxygen demand. No evidence of myocardial failure in normal hearts due to excess exercise has been present...
Pascoe JR, McCabe AE, Franti CE, Arthur RM.The repeatability of endoscopic observations of exercise-induced pulmonary hemorrhage (EIPH) and the efficacy of furosemide as a prophylactic treatment of horses with EIPH were studied in Thoroughbred race horses after consecutive breezes (at or near maximum speed, approx 16 m/s). Of 56 horses examined greater than or equal to 2 times, 21 (38%) had identical EIPH scores, whereas 26 (46%) and 9 (16%) had scores that differed by greater than or equal to 1 grade. In 56 nontreated horses, there was good agreement between 2 consecutive observations (K = 0.59, Z = 4.54, P less than 0.001). Similar c...
Clarke AF.Exercise induced pulmonary haemorrhage (EIPH) is a condition of uncertain aetiology. This article reviews the evidence relating to its incidence, clinical findings, radiological observations, histopathology and certain aspects of respiratory physiology. It is proposed that EIPH is primarily caused by mechanical stress in the dorsocaudal region of the lung.
Soma LR, Laster L, Oppenlander F, Barr-Alderfer V.In 3 groups of horses with exercise-induced pulmonary hemorrhage (EIPH), comparisons of racing times and finishing positions were made between the 5 races before the horses were given furosemide and 5 races after furosemide administration. The horses were grouped according to 3 methods used to diagnose EIPH: group 1, observation of hemorrhage at the nostrils within 1 hour after a workout or race; group 2, observation of pulmonary hemorrhage only by endoscopic examination after a race or workout; and group 3, observation of hemorrhage at the nostrils during a race or immediately after a race. G...
Burrell MH.A group of racehorses in training was examined on several occasions with a fibreoptic endoscope and monitored for viral infection. Only equine herpes virus-2 (EHV-2) infection was detected. Pharyngeal lymphoid hyperplasia (PLH) was present in all horses and decreased in severity with age. There was no association between PLH severity and antibody titres to EHV-1, or with the isolation of EHV-2. Finishing position in races was not affected by PLH severity. Exercise induced pulmonary haemorrhage (EIPH) was evident on 23 out of 49 (47 per cent) examinations after maximal speed training exercise. ...
Mason DK, Collins EA, Watkins KL.An investigation into the incidence of exercise induced pulmonary haemorrhage (EIPH) in thoroughbreds in Hong Kong was carried out between the 1981 and 1983 racing seasons. A total of 1039 post race endoscopic examinations were performed in 1982-1983 and the results indicated that 46.8 per cent of runners had EIPH. This was not statistically different from the percentage of horses showing EIPH during 1981-82 (46.9 per cent). As it had been postulated that dust, especially from straw, could be implicated in lung haemorrhage a proportion of horses were bedded on paper in the 1982-83 season. No s...
Sweeney CR, Soma LR.Of 61 horses with a history of exercise-induced pulmonary hemorrhage and treated with furosemide 4 hours prior to racing, 34 (55.7%) continued to bleed. Of 24 horses with exercise-induced pulmonary hemorrhage that were not treated with furosemide prior to racing, 17 (70.8%) still bled. There was no statistically significant difference between the treated and the nontreated groups. Of 45 horses given hesperidin-citrus bioflavinoids, 38 (84.4%) bled when exercised 90 days later. There was no statistically significant difference between the results for hesperidin-citrus bioflavinoid-treated horse...
Sweeney CR, Soma LR, Bucan CA, Ray SG.Thoroughbreds with a confirmed history of exercise-induced pulmonary hemorrhage (EIPH) were treated pre-exercise with atropine sulfate, cromolyn, ipratropium or furosemide. Atropine prevented EIPH in 3 of 3 trials in 1 horse, while having no significant effect on bleeding status in the other 2 horses. Pre-exercise treatment with cromolyn had no significant effects in the 3 horses. Pre-exercise treatment of ipratropium was apparently responsible for preventing EIPH in 17 out of 18 trials in 2 horses. The pharmacologic properties of ipratropium in the horse have not been studied, but based on hu...
Littlejohn A, Howell W, Killeen V.In ten Thoroughbred racehorses which suffered epistaxis during a race, the mean pulmonary arterial diastolic pressure (PADP) was significantly higher, and the mean pulmonary arterial oxygen tension (PaO2) was significantly lower, than the corresponding mean values of a sample of fourteen clinically normal Thoroughbreds in training. The authors conclude that in horses with epistaxis during a race, pulmonary dysfunction may persist for up to two months after the episode, and that the results indicate a need for pulmonary function studies before and after racing, in order to resolve problems conc...
Raphel CF.A flexible fiberoptic endoscope was used to examine the upper respiratory tract of 479 horses and 41 (8.6%) had abnormalities. Pharyngeal lymphoid hyperplasia (PLH) was found in 141 horses (29.5%). Statistical analysis showed a relationship between the age of the horse and the prevalence of PLH. Sixteen (3.3%), 10 (2.1%), and 6 (1.3%), of the horses had laryngeal hemiplegia, epiglottic entrapment, and dorsal displacement of the soft palate, respectively. There was no association between the age of the horse and the prevalence of any of these abnormalities; nor was there a positive correlation ...
O'Callaghan MW, Goulden BE.This paper describes the distinctive radiographic changes detected in the dorso-caudal lungfields of four racing thoroughbreds recently affected by exercise-induced epistaxis. A diffuse but localized increase in density was seen in all four cases, which demonstrated a variation from a predominantly alveolar density to an interstitial pattern and finally to increased bronchial markings. Evolution of the radiographic pattern of the pulmonary densities appeared to be related to the time that had elapsed since the bleeding incident. The implications of the changing pattern and site of the densitie...
Speirs VC, van Veenendaal JC, Harrison IW, Smyth GB, Anderson GA, Wilson DV, Gilbo B.Endoscopic examinations of the upper respiratory tract were done on 92 of 314 Standardbred horses that raced one or more times at 4 consecutive, weekly race meetings. Although participation was voluntary, the characteristics of the population of horses examined were not statistically different from those of all horses that raced. No horse showed epistaxis, but 34 (32.4%) examinations of the trachea revealed blood that ranged from a trace in the tracheal mucus to large amounts scattered over the tracheal walls. Forty-four horses exhibited minor degrees of pharyngeal lymphoid hyperplasia, 2 had ...
Manohar M, Goetz TE, Hassan AS.Recently, it was reported that acute hypervolemia improves arterial oxygen tension in human athletes known to experience exercise-induced arterial hypoxemia. Since exercise-induced arterial hypoxemia is routinely observed in racehorses and is known to limit performance, we examined whether pre-exercise induction of acute hypervolemia would similarly benefit arterial oxygenation in maximally exercising thoroughbred horses. Two sets of experiments, namely, placebo [intravenous (IV) physiological saline] and acute hypervolemia (IV 7.2% NaCl, causing an 18.2% expansion of plasma volume) studies we...
Mason DK, Collins EA, Watkins KL.An investigation into the incidence of exercise induced pulmonary haemorrhage (EIPH) in thoroughbreds in Hong Kong was carried out between the 1981 and 1983 racing seasons. A total of 1039 post race endoscopic examinations were performed in 1982-1983 and the results indicated that 46.8 per cent of runners had EIPH. This was not statistically different from the percentage of horses showing EIPH during 1981-82 (46.9 per cent). As it had been postulated that dust, especially from straw, could be implicated in lung haemorrhage a proportion of horses were bedded on paper in the 1982-83 season. No s...
Pfaff G.In South Africa 2,41% of horses bleed in a race. If all raced until they were 7 years old probably another 2,12% would bleed. Many others bleed after the race or during exercise or at rest. The incidence of epistaxis is significantly greater in geldings than in females and uncastrated males (P less than 0,001). There is an age distribution of bleeding which is highest at 4 years and lowest at 2 years of age (P less than 0,001).
Hillidge CJ, Whitlock TW.Post race endoscopy was carried out on 255 two-year-old quarter horses and exercise-induced pulmonary haemorrhage (EIPH) was diagnosed in 166 (65 per cent) of them. Visible epistaxis was seen in a higher proportion of geldings than in either mares or stallions. The prevalence of EIPH was similar in mares (73 per cent) and in geldings (74 per cent). A significantly lower prevalence (49 per cent) was noted in stallions (P less than 0.01). It was concluded that a sex variation in the prevalence of EIPH exists in two-year-old quarter horses.
Hinchcliff KW, Mitten LA.Furosemide and, less commonly, bumetanide and ethacrynic acid are potent diuretics administered to horses for a variety of reasons, including prophylaxis of exercise-induced pulmonary hemorrhage. These drugs affect urine volume and composition, and furosemide has marked effects on plasma volume and composition and on systemic hemodynamics at rest and during exercise.
Clarke AF.Exercise induced pulmonary haemorrhage (EIPH) is a condition of uncertain aetiology. This article reviews the evidence relating to its incidence, clinical findings, radiological observations, histopathology and certain aspects of respiratory physiology. It is proposed that EIPH is primarily caused by mechanical stress in the dorsocaudal region of the lung.
Johnson AT, Soma LR, Ferouz C.Exercise-induced pulmonary hemorrhage (EIPH) affects a large portion of racing thoroughbred horses. Sites of hemorrhage and causal mechanisms remain unestablished. Our mathematical model was constructed to test the hypothesis that EIPH could be caused by a combination of respiratory and circulatory mechanical factors occurring during exercise. Various physiological data for respiration, blood circulation and exercise were incorporated into the model. Results show that inhalation pressure drops across airway resistances become great enough during exercise to cause rupture of capillaries for bot...
Knych HK, Wilson WD, Vale A, Kass PH, Steffey EP, Jones JH, Arthur RM.Although controversial, due to its reported effectiveness in attenuating bleeding associated with exercise-induced pulmonary hemorrhage (EIPH), furosemide is currently a permitted race day medication in most North American racing jurisdictions. The objective of this study was to assess the efficacy of furosemide in reducing the presence and severity of EIPH when administered 24 hr prior to strenuous treadmill exercise. Eight exercised Thoroughbred horses received saline or 250 mg of furosemide either 4 or 24 hr prior to high-speed treadmill exercise in a balanced 3-way cross-over design. Bl...
Deaton CM, Brown-Feltner H, Henley WE, Roberts CA, Lekeux P, Schroter RC, Marlin DJ.Pulmonary capillary stress failure, largely as a result of high pulmonary vascular pressures, has been implicated in the aetiology of EIPH. However, the role of the respiratory system in determining the magnitude of EIPH has received little attention. Objective: Horses breathing a gas of greater density than air will exhibit greater transmural pulmonary arterial pressures (TPAP) and more severe EIPH, and horses breathing a gas of lower density than air will exhibit lower TPAP and less severe EIPH, both compared with horses breathing air. Methods: Following a warm-up, 8 Thoroughbred horses were...
O'Callaghan MW.When performed on selected clinical cases, ventilation/perfusion scintigraphy provides valuable additional information on regional lung function that is not obtainable from conventional thoracic radiographs. This is particularly true of horses with EIPH, COPD, and those suspected of having some form of small-airway disease. For horses with EIPH, the presence of a perfusion deficit on the scan is considered a key prognostic sign, because it is likely in these cases that irreversible bronchial arterial takeover has occurred in the affected areas of lung. Findings from horses with COPD have impro...
Arthur RM.Racetracks are ideal environments for the promotion of lower respiratory disease. The stabling is close and unclean, the population is nationally and internationally mobile, and the work the racehorse performs is traumatic to the respiratory tract. The running horse must complete a respiratory cycle with each stride. This relationship requires 130-150 breaths a minute in the running horse. Minute volume has been measured at 1300 L per minute and peak flow rates of 60 L/second in horses traveling at a modest 8 meters per second. As a comparison, the fastest running horse approaches 18 meters pe...
Foreman JH.Differentiation of diseases of the equine respiratory tract is based on history, clinical signs, auscultation, endoscopy, imaging, and sampling of airway exudate. Upper respiratory therapies include surgical correction of airway obstructions; flushing of localized abscesses (strangles), guttural pouch disease, or sinusitis; and oral or parenteral antibiotic and anti-inflammatory therapy if deemed necessary. Pneumonia usually is treated with antimicrobials, anti-inflammatories, and bronchodilators. Pleural drainage is indicated if significant pleural effusion is present. The most commonly used ...
Aguilera-Tejero E, Pascoe JR, Smith BL, Tyler WS, Woliner MJ.The diffusing capacity for carbon monoxide (DLCO) and the functional residual capacity (FRC) of the lung were measured in 5 healthy Thoroughbreds before and after instillation of autologous blood into their lungs, in an attempt to develop a method to quantitate extravascular blood in the lungs of horses with exercise-induced pulmonary hemorrhage. Mean (+/- SD) baseline values of DLCO and FRC were 333.8 +/- 61.9 ml/min/mm of Hg and 21.464 +/- 4.156 L, respectively. Blood instillation resulted in decreases in DLCO and FRC. The paradoxic decrease in DLCO (we were expecting to find an increase owi...
Funkquist P, Sandhagen B, Persson SG, Hedenstierna G, Essén-Gustavsson B, Nyman G.Five Standardbred trotters with red cell hypervolaemia (RCHV) were compared before and after removal of approximately 22% (36 ml/kg bwt) of the total blood volume in order to evaluate the haemodynamic responses, haemorheological alterations and oxygen transport during exercise to fatigue. Data were recorded during submaximal exercise at 4 different speeds on a treadmill and then during continued running at the highest speed step until fatigue. Oxygen uptake (VO2), pulmonary artery pressure (PAP), systemic artery pressure (SAP), heart rate (HR), haematocrit and haemoglobin concentrations (Hb) w...
Maxwell L, McCarrel TM, Hay S, Cole C.The antifibrinolytic agent aminocaproic acid (ACA) is occasionally used prior to episodes of intense training in racehorses suffering from exercise-induced pulmonary hemorrhage. Although a previous study indicated that the drug is cleared rapidly in horses, some racetrack practitioners claim that recent adverse analytical findings for ACA in postrace samples were from ACA administrations 5-7 days before the race. The purpose of this study was to re-examine the pharmacokinetics of ACA in horses to address this apparent conundrum. Eight exercise-conditioned thoroughbred horses were administere...
Morrison KE, Slocombe RF, McKane SA, Dargaville PA.Pulmonary surfactant from bronchoalveolar lavages was obtained from 2 groups of horses. A control group consisting of 6 healthy racehorses that were paddock-rested and lavaged weekly for 6 consecutive weeks were compared with an experimental group of 10 healthy racehorses, lavaged weekly the same period, consisting of a 5 week incremental-intensity treadmill training programme and one week post training paddock rest. Phospholipid content of lavage fluid was determined indirectly by phosphorus assay, and surfactant functional activity was determined by bubble surfactometry. Total cell counts an...
Manohar M, Goetz TE, Hassan AS, Rothenbaum P, Humphrey S.The present study was carried out to determine whether inhibition of nitric oxide (NO) synthase promotes anaerobic metabolism in exercising horses, resulting in a significantly increased blood lactate concentration. N(omega)-nitro-L-arginine methyl ester (L-NAME) is a potent inhibitor of NO synthase that has been tested in horses and other species. Two sets of experiments, namely placebo (saline control) and L-NAME (20 mg/kg, i.v.) studies, were carried out on seven healthy, sound, exercise-trained, Thoroughbred horses in random order, 6 to 7 days apart. In both experiments, an incremental exe...
Olsen SC, Coyne CP, Lowe BS, Pelletier N, Raub EM, Erickson HH.Furosemide, which commonly is used as a prophylactic treatment for exercise-induced pulmonary hemorrhage in horses, may mediate hemodynamic changes during exercise by altering prostaglandin metabolism. To determine if furosemide's hemodynamic effects during exercise in horses could be reversed, cyclooxygenase inhibitors were administered with furosemide. Four treatments were administered 4 hours prior to treadmill exercise at 9 and 13 m/s. They included a control treatment (10 ml of 0.9% NaCl solution, IV), furosemide (1 mg/kg of body weight, IV) administered alone, and furosemide in combinati...
Warlick LM, Léguillette R, Kogan C, Gold JR, Bayly WM.Diagnosis and assessment of severity of exercise-induced pulmonary hemorrhage (EIPH) relies on postexercise visualization of fresh blood in the airways via tracheobronchoscopic examination (TBE) and/or counting erythrocytes in bronchoalveolar lavage fluid (BALFRBC). Determining the BALFRBC is more sensitive than TBE but its usefulness is hampered by the need to have BALFRBC counted at a laboratory. We explored the feasibility of evaluating the severity of EIPH by using a color chart comprised of five shades of red and matching those colors with the color of BALF immediately following collectio...
Uboh CE, Soma LR, Rudy JA, Morgan E, Mengeringhausen K, Sams R.This study was undertaken to determine the applicability of plasma concentration of furosemide and specific gravity (SG) of urine in regulating the use of furosemide administered 4 hours prior to race time in Exercise-Induced Pulmonary Hemorrhage (EIPH) race horses. Nonbleeders (CTL) and certified bleeders (FUR) actively racing in Illinois (IL) and Pennsylvania (PA) were used in the study. Various doses (less than 250, 250, 300, 350, 400 and 500 mg) were administered either as a single intravenous (IV) dose or as a combination (IV-IM) of IV and intramuscular (IM) administrations 4 hours before...
Lawn K.During training, a 6-year-old standardbred gelding collapsed, exhibiting severe epistaxis and agonal breathing and was euthanized. The horse had a recent history of poor performance, lethargy, and unilateral eyelid swelling with serous ocular discharge. Postmortem and histopathologic examination findings revealed thoracic lymphosarcoma and concurrent exercise-induced pulmonary hemorrhage. Résumé — Mort subite d’un cheval de course de race standardbred causée par un lymphome thoracique. En cours d’entraînement, un standardbred hongre âgé de 6 ans s’est effondré, présentant des s...
Art T, Tack S, Kirschvinck N, Busoni V, Votion D, Freeman K, Lekeux P.This study aimed at measuring the functional consequences and the pulmonary cytology changes following a simulation of pulmonary haemorrhage. Pulmonary function tests including lobeline-induced hyperventilation, cytology of tracheo-bronchial wash (TBW) and thoracic radiographs were performed before, as well as 1, 7, 14 and 28 days after, the instillation of 300 ml of blood into the lungs of 4 horses deemed free of exercise-induced pulmonary haemorrhage (Group 1). Control data (Group 2) were obtained by instilling the same volume of saline into the lungs of the same horses in a crossover design...
McCrae P, Guigand C, Jones KB, Thueson ES, Troudt TA, Warlick LM, Sides RH, Jones JH, Bayly WM, Léguillette R.High pulmonary blood pressure contributes to exercise-induced pulmonary hemorrhage. The objective of this study was to use bioimpedance spectroscopy to assess body fluid compartment volumes under 3 conditions in 6 racehorses: i) Pre- and post-supramaximal treadmill exercise (control); ii) Exercise 4 hours after furosemide (0.5 mg/kg body weight, IV); iii) Exercise, removal of ~14 L of blood and subsequent reinfusion of the blood. Statistical analysis used linear mixed effects models. Body compartment volumes did not change during the control runs. Total body water (TBW) ( = 0.007, = 0.007), e...
Mazan MR.The airways are the first part of the pathway in the oxygen transport chain that is critical to excellent athletic performance, and the lower airways are considered the final gatekeeper before oxygen enters the blood and carbon dioxide exits. Horses are blessed with large airways and lungs that allow them to be superb athletes, but the down side of this largesse on the part of evolution is that unless they are truly elite athletes they may withstand noninfectious disease of the lower respiratory tract for months to years before the owner or trainer notices. The two conditions of the lower resp...
Bove AA.Myocardial blood flow is the major determinant of oxygen delivery to the myocardium, since oxygen extraction by the myocardium is near maximum in the resting state. Regulation of flow during exercise depends on local metabolic factors and, to a small extent, on autonomic tone. Maximum flow of 5-6 times resting has been measured in reactive hyperemia experiments. In strenuous exercise, myocardial oxygen delivery appears to be adequate and flow reserve seems capable of handling the increased oxygen demand. No evidence of myocardial failure in normal hearts due to excess exercise has been present...
Young LE, Helwegen MM, Rogers K, Kearns L, Schreiber C, Wood JL.Exercise-induced pulmonary haemorrhage (EIPH) and tricuspid (TR) and mitral valve regurgitation (MR) are conditions with high prevalence in conditioned Thoroughbreds. Stress failure of pulmonary capillaries, leading to EIPH, is most likely when pulmonary vascular pressure is increased, and mitral regurgitation can result in pulmonary venous hypertension. Objective: There might be an association between MR and EIPH and the right ventricle (RV) of horses known to suffer repeated episodes of EIPH, as their hearts would be subject to higher pulmonary vascular pressures and cardiac output during tr...
Dirikolu L, Lehner AF, Hughes C, Karpiesiuk W, Camargo FC, Harkins JD, Woods WE, Bosken JM, Boyles J, Troppmann A, Fisher M, Tobin T.Furosemide is a potent loop diuretic used for the prevention of exercise-induced pulmonary hemorrhage in horses. This drug may interfere with the detection of other substances by reducing urinary concentrations, so its use is strictly regulated. The regulation of furosemide in many racing jurisdictions is based on paired limits of urinary SG (100 ng/ml). To validate this regulatory mechanism, a liquid chromatography/mass spectrometry/mass spectrometry method employing a solid-phase extraction procedure and furosemide-d5 as an internal standard was developed. The method was used to determine th...
Thorpe CT, Marlin DJ, Franklin SH, Colborne GR.Changes in shape of the equine thorax during locomotion are not well defined, although it has been shown recently that the transverse hemi-diameter changes its dimension by up to 80mm on the side of the trailing forelimb during gallop, despite minimal change in thoracic circumference. The aim of this project was to analyse transverse and dorso-ventral changes in shape of the thorax simultaneously, and to determine if leading limb, treadmill slope and speed have an effect on these shape changes. Reflective markers were placed on the horse's hemi-thorax and movement of the markers was recorded u...
