[en] REASONS FOR PERFORMING STUDY: 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. HYPOTHESIS: 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 exercised for 1 min at 10, 11 and 12 m/sec (5 degrees incline) breathing air or 21% oxygen/79% helium or 21% oxygen/79% argon in a randomised order. Heart rate, respiratory rate, pulmonary arterial pressure and oesophageal pressure were measured during exercise. Bronchoalveolar lavage fluid (BALF) was collected from the dorsocaudal regions of the left and right lungs 40 min post exercise and red blood cell (RBC) counts were performed. RESULTS: The exercise tests induced mild EIPH. Maximum changes in oesophageal pressure were lower on helium-oxygen compared to argon-oxygen (P<0.001). TPAP and median RBC counts did not differ between gas mixtures. BALF RBC counts from the left lung correlated with counts from the right lung (P<0.0001). However BALF RBC counts from the left lung were higher than those from the right lung (P = 0.004). CONCLUSION: As alterations in pulmonary arterial and oesophageal pressure caused by changes in inspired gas density were of similar magnitude, TPAP remained unchanged and there was no significant effect on EIPH severity. POTENTIAL RELEVANCE: Manipulations that decrease swings in intrapleural pressure may only decrease the degree of EIPH in horses severely affected by the condition
Disciplines :
Veterinary medicine & animal health
Author, co-author :
Deaton, C. M.; Animal Health Trust, Lanwades Park, Kentford, Suffolk, UK
Brown-Feltner, H.; Animal Health Trust, Lanwades Park, Kentford, Suffolk, UK
Henley, W. E.; Animal Health Trust, Lanwades Park, Kentford, Suffolk, UK
Roberts, C. A.; University of Cambridge > Department of Clinical Veterinary Medicine
Lekeux, Pierre ; Université de Liège - ULiège > Département de sciences fonctionnelles > Physiologie - Doyen de la Faculté de Médecine vétérinaire
Schroter, R. C.; Imperial College London, London, UK > Department of Bioengineering
Marlin, D. J.; Animal Health Trust, Lanwades Park, Kentford, Suffolk, UK
Language :
English
Title :
The effect of inspired gas density on pulmonary artery transmural pressure and exercise induced pulmonary haemorrhage
Publication date :
2006
Journal title :
Equine Veterinary Journal
ISSN :
0425-1644
eISSN :
2042-3306
Publisher :
Equine Veterinary Journal Ltd, Newmarket Suffolk, United Kingdom
Art, T., Serteyn, D. and Lekeux, P. (1988) Effect of exercise on the partitioning of equine respiratory resistance. Equine vet. J. 20, 268-273.
Art, T., Desmecht, D., Amory, H. and Lekeux, P. (1991) Heliox-induced changes in the breathing mechanics of ponies during exercise. In: Equine Exercise Physiology, Eds: S. G. B. Persson, A. Lindholm and L. B. Jeffcott, ICEEP, Uppsala, pp 47-53.
Birks, E. K., Mathieu-Costello, O., Fu, Z., Tyler, W. S. and West, J. B. (1997) Very high pressures are required to cause stress failure of pulmonary capillaries in thoroughbred racehorses. J. appl. Physiol. 82, 1584-1592.
Birks, E. K., Shuler, K. M., Soma, L. R., Martin, B. B., Marconato, L., Del Piero, F., Teleis, D. C., Schar, D., Hessinger, A. E. and Uboh, C. E. (2002) EIPH: postrace endoscopic evaluation of Standardbreds and Thoroughbreds. Equine vet. J., Suppl. 34, 375-378.
Ducharme, N. G., Hackett, R. P., Gleed, R. D., Ainsworth, D. M., Erb, H. N., Mitchell, L. M. and Soderholm, L. V. (1999) Pulmonary capillary pressure in horses undergoing alteration of pleural pressure by imposition of various upper airway resistive loads. Equine vet. J., Suppl. 30, 27-33.
Erickson, B. K., Erickson, H. H. and Coffman, J. R. (1990) Pulmonary artery, aortic and oesophageal pressure changes during high intensity treadmill exercise in the horse: a possible relation to exercise-induced pulmonary haemorrhage. Equine vet. J., Suppl. 9, 47-52.
Erickson, B. K., Pieschl, R. L. and Erickson, H. H. (1991) Alleviation of exercise-induced hypoxemia utilising inspired 79% helium 20.95% oxygen. In: Equine Exercise Physiology, Eds: S. G. B. Persson, A. Lindholm and L. B. Jeffcott, ICEEP, Uppsala, pp 54-58.
Erickson, B. K., Seaman, J., Kubo, K., Hiraga, A., Kai, M., Yamaya, Y. and Wagner, P. D. (1994) Mechanism of reduction in alveolar-arterial PO2 difference by helium breathing in the exercising horse. J. appl. Physiol. 76, 2794-2801.
Geor, R. J., Ommundson, L., Fenton, G. and Pagan, J. D. (2001) Effects of an external nasal strip and frusemide on pulmonary haemorrhage in Thoroughbreds following high-intensity exercise. Equine vet. J. 33, 577-584.
Goetz, T. E., Manohar, M., Hassan, A. S. and Baker, G. J. (2001) Nasal strips do not affect pulmonary gas exchange, anaerobic metabolism, or EIPH in exercising Thoroughbreds. J. appl. Physiol. 90, 2378-2385.
Hinchcliff, K. W., Jackson, M. A., Morley, P. S., Brown, J. A., Dredge, A. E., O'Callaghan, P. A., McCaffrey, J. P., Slocombe, R. E. and Clarke, A. E. (2005) Association between exercise-induced pulmonary hemorrhage and performance in Thoroughbred racehorses. J. Am. vet. med. Ass. 227, 768-774.
Holcombe, S. J., Berney, C., Cornelisse, C. J., Derksen, F. J. and Robinson, N. E. (2002) Effect of commercially available nasal strips on airway resistance in exercising horses. Am. J. vet. Res. 63, 1101-1105.
Jackson, J. A., Ducharme, N. G., Hackett, R. P., Rehder, R. S., Ainsworth, D. M., Shannon, K. J., Erickson, B. K., Erb, H. N., Jansson, N., Soderholm, L. V., Jr. and Thorson, L. M. (1997) Effects of airway obstruction on transmural pulmonary artery pressure in exercising horses. Am. J. vet. Res. 58, 897-903.
Kindig, C. A., McDonough, P., Fenton, G., Poole, D. C. and Erickson, H. H. (2001) Efficacy of nasal strip and furosemide in mitigating EIPH in Thoroughbred horses. J. appl. Physiol. 91, 1396-1400.
Kindig, C. A., Ramsel, C., McDonough, P., Poole, D. C. and Erickson, H. H. (2003) Inclined running increases pulmonary haemorrhage in the Thoroughbred horse. Equine vet. J. 35, 581-585.
Kramer, C. Y. (1956) Extension of multiple range tests to group means with unequal numbers of replications. Biometrics 12, 309-310.
Langsetmo, I., Meyer, M. R. and Erickson, H. H. (2000) Relationship of pulmonary arterial pressure to pulmonary haemorrhage in exercising horses. Equine vet. J. 32, 379-384.
Lester, G., Clark, C., Rice, B., Steible-Hartless, C. and Vetro-Widenhouse, T. (1999) Effect of timing and route of administration of furosemide on pulmonary hemorrhage and pulmonary arterial pressure in exercising thoroughbred racehorses. Am. J. vet. Res. 60, 22-28.
McKane, S. A., Canfield, P. J. and Rose, R. J. (1993) Equine bronchoalveolar lavage cytology: survey of thoroughbred racehorses in training. Aust. vet. J. 70, 401-404.
Meyer, T. S., Fedde, M. R., Gaughan, E. M., Langsetmo, I. and Erickson, H. H. (1998) Quantification of exercise-induced pulmonary haemorrhage with bronchoalveolar lavage. Equine vet. J. 30, 284-288.
Pan, L. G., Forster, H. V., Bisgard, G. E., Lowry, T. F. and Murphy, C. L. (1987) Role of carotid chemoreceptors and pulmonary vagal afferents during helium-oxygen breathing in ponies. J. appl. Physiol. 62, 1020-1027.
Pascoe, J. R., Ferraro, G. L., Cannon, J. H., Arthur, R. M. and Wheat, J. D. (1981) Exercise-induced pulmonary hemorrhage in racing thoroughbreds: a preliminary study. Am. J. vet. Res. 42, 703-707.
Pedley, T. J., Schroter, R. C. and Sudlow, M. F. (1970) The prediction of pressure drop and variation of resistance within the human bronchial airways. Respir. Physiol. 9, 387-405.
Valdez, S. C., Nieto, J. E., Spier, S. J., Owens, S. D., Beldomenico, P. and Snyder, J. R. (2004) Effect of an external nasal dilator strip on cytologic characteristics of bronchoalveolar lavage fluid in Thoroughbred racehorses. J. Am. vet. med. Ass. 224, 558-561.
West, J. B., Mathieu-Costello, O., Jones, J. H., Birks, E. K., Logemann, R. B., Pascoe, J. R. and Tyler, W. S. (1993) Stress failure of pulmonary capillaries in racehorses with exercise-induced pulmonary hemorrhage. J. appl. Physiol. 75, 1097-1109.
