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Pleural pressure changes during exercise do not affect measurement of mean pulmonary vascular pressures
Author(s) -
SINHA A. K.,
HAKIM T. S.,
GLEED R. D.,
DOBSON A.
Publication year - 1995
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1995.tb04897.x
Subject(s) - pulmonary wedge pressure , medicine , cardiology , pulmonary artery , mean arterial pressure , blood pressure , heart rate
Summary This study was designed to evaluate the influence of pleural pressure on mean pulmonary vascular pressures in exercising horses. Pulmonary artery (Pa), pulmonary wedge (P w ) and oesophageal pressures (P es ) were measured with transducer tip catheters in 6 Standardbred horses at rest and during treadmill exercise at 75, 90 and 100% of maximal heart rate. Oesophageal pressure (P es ) measurements were used to estimate pleural pressure. Vascular pressures were determined in 4 ways: 1) mean transmural vascular pressure (P tm ) at P es equal to resting end expiratory pressure; 2) mean P tm at P es equal to mean P es for the data collection period; 3) mean P tm without selection of specific data points and 4) mean pulmonary vascular pressure relative to atmospheric pressure (conventional method). Despite large fluctuations associated with breathing, mean P es during exercise remained close to zero, suggesting that pleural pressure fluctuates equally about zero. The swings in P es were associated with approximately equal swings in vascular pressure so that, despite the marked fluctuations, mean P a and P w determined with the 4 methods were not significantly different. The results indicate that during exercise it is valid to report mean pulmonary vascular pressures without accounting for the fluctuations in pleural pressure.