Evaluation of a mask for breath-by-breath respirometry during exercise in horses.

The study evaluates a new ergospirometry system (for measuring respiratory variables) called Quadflow (QF) in contrast to an established system, using Thoroughbred horses during high-speed exercise tests. The results demonstrated the new system can measure horse pulmonary airflows and volumes reliably, even though it had greater airflow resistance and significantly altered blood gases, respiratory parameters, and performance compared to the control system.

Evaluation Methods

• The researchers carried out 10 incremental exercise tests to fatigue on five Thoroughbred horses. Each horse carried out five tests with the QF system and five with a standard, open-circuit flow system (seen as the control).
• Several measurements were taken including heart rate, pulmonary variables, and arterial blood gases. The researchers also noted the time to fatigue and the distance run.
• The results from each system were compared to assess their similarity and their impacts on performance.

Results of Evaluation

• The research found a high repeatability of results from both the open-circuit flow system as well as the QF system, evidenced by low coefficients of variation.
• It was found that the QF system was related with greater resistance to airflow, higher breathing rate at submaximal speeds, lower minute ventilation and peak inspiratory and expiratory airflows.
• The QF system demonstrated greater acidaemia (increased acidity of the blood), hypoxaemia (low oxygen levels in the blood) and hypercapnoea (elevated levels of carbon dioxide in the blood).
• The researchers also noted a decrease in total run time and total distance run when the QF system was used in comparison to the traditional system.

Conclusions of the Research

• The researchers concluded that the greater resistance of the QF system resulted in altered blood gases, respiratory parameters and performance when compared to the traditional mask.
• However, they found that the QF system could reliably measure equine pulmonary airflows and volumes.
• The authors suggest the QF system is suitable for both research and clinical uses as long as optimal gas exchange and top-level physical performance are not required.