Document Detail

Exercise-induced pulmonary haemorrhage during submaximal exercise.
MedLine Citation:
PMID:  17402474     Owner:  NLM     Status:  MEDLINE    
REASONS FOR PERFORMING STUDY: Maximally exercising horses achieve mean pulmonary artery pressures (Ppa(mean)) that exceed the minimum threshold (75 mmHg) estimated for pulmonary capillary rupture and exercise-induced pulmonary haemorrhage (EIPH). EIPH is not expected to occur during moderate submaximal exercise (i.e. 40-60% VO2max) since Ppa(mean) remains well below this threshold. HYPOTHESIS: Prolonged submaximal exercise (trotting) would precipitate locomotory respiratory uncoupling and cause EIPH. This would be present as a result of the most negative intrapleural pressures (as estimated by the minimum oesophageal pressure; Poes(min)) occurring simultaneously with the most positive Ppa (Ppa(peak)) to produce estimated maximal pulmonary artery transmural pressures (PATMPmax) that surpass the EIPH threshold. METHODS: Five Thoroughbred horses trotted to fatigue (approximately 25 min) at 5 m/sec on a 10% incline. Ventilation (V(E)), Poes, and Ppa were measured at 5 min intervals, and bronchoalveolar lavage (BAL) red blood cells (RBCs) were quantified 45 min post exercise. RESULTS: BAL revealed an increased EIPH (rest: 2.0 +/- 1 x 10(5), exercise: 17 +/- 10 x 10(5) RBCs/ml BALF; P<0.05), despite the highest Ppamean reaching only mean +/- s.e. 55 +/- 3 mmHg, while V(E), tidal volume and Poes(min) approached 70-80% of the values achieved at maximal running speeds (10% incline: 12-13 m/sec) by these same horses. The resulting PATMPmax was well above the level considered causative of EIPH. CONCLUSIONS: The finding of significant EIPH during submaximal exercise broadens the spectrum of performance horses susceptible to EIPH and supports studies that suggest that extravascular factors are of primary importance in the aetiology of EIPH. POTENTIAL RELEVANCE: Consideration of strategies such as the equine nasal strip for reducing negative extravascular pressures is warranted even for exercise at moderate intensities.
T S Epp; P McDonough; D J Padilla; J M Gentile; K L Edwards; H H Erickson; D C Poole
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Equine veterinary journal. Supplement     Volume:  -     ISSN:  -     ISO Abbreviation:  Equine Vet J Suppl     Publication Date:  2006 Aug 
Date Detail:
Created Date:  2007-04-03     Completed Date:  2007-05-02     Revised Date:  2007-05-18    
Medline Journal Info:
Nlm Unique ID:  9614088     Medline TA:  Equine Vet J Suppl     Country:  England    
Other Details:
Languages:  eng     Pagination:  502-7     Citation Subset:  IM    
Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506, USA.
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MeSH Terms
Blood Gas Analysis / veterinary
Bronchoalveolar Lavage Fluid / cytology
Erythrocyte Count / veterinary
Hemorrhage / etiology,  veterinary*
Horse Diseases / etiology*
Lung Diseases / etiology,  veterinary*
Oxygen Consumption
Physical Conditioning, Animal* / adverse effects,  physiology
Pulmonary Artery / physiology
Pulmonary Circulation / physiology
Pulmonary Wedge Pressure / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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