Evaluation of a mask for breath-by-breath respirometry during exercise in horses.
BACKGROUND
The ability to obtain breath-by-breath measures of ventilatory mechanics for the entirety of an exercise test, regardless of speed(s) or duration enables evaluations of equine ventilation during exercise that are necessary for assessments of performance.


OBJECTIVE
Evaluation of a new ergospirometer (Quadflow; QF) system's accuracy and repeatability for measuring pulmonary variables in contrast to the established pneumotachometer-based system (control) and assessment of its effects, if any, on exercise capacity at high speeds.


METHODS
Five Thoroughbred horses each performed 10 incremental exercise tests to fatigue, 5 with the QF system and 5 with an open-circuit flow system. Measures of pulmonary variables were evaluated to determine repeatability. Heart rate, pulmonary variables, arterial blood gases, distance run and time to fatigue measured with each system were compared to assess similarity of results and effect on performance.


RESULTS
Results from both systems had high repeatability with low coefficients of variation. The QF was associated with greater resistance to airflow, higher breathing rate at submaximal speeds, lower minute ventilation and peak inspiratory and expiratory airflows, greater acidaemia, hypoxaemia and hypercapnoea, and decreased total run time and total distance run when compared to control system results.


CONCLUSIONS
The greater resistance of the QF was responsible for altered blood gases, respiratory parameters and performance when compared to the control mask. The QF system reliably measured equine pulmonary airflows and volumes and is suitable for research and clinical use provided optimal gas exchange and best possible physical performance are not required.
Department of Veterinary Clinical Sciences, Washington State University College of Veterinary Medicine, Pullman, Washington, USA.
A
A
Ramseyer
R
R
Sides
B
B
Slinker
D
D
Evans
W
W
Bayly
D000818:Animals; D001831:Body Temperature; D006339:Heart Rate; D006736:Horses / Q000502:physiology*; D008297:Male; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D015203:Reproducibility of Results; D012143:Respiratory Physiological Phenomena; D056152:Respiratory Rate / Q000502:physiology; D013147:Spirometry / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*