Effect of combined staphylectomy and laryngotomy on upper airway mechanics in clinically normal horses

Abstract

Objective - To investigate the effect of combined staphylectomy and laryngotomy on upper airway mechanics in clinically normal horses running on a treadmill. Animals - 6 Standardbreds. Procedure - Upper airway mechanics were measured with horses trotting or pacing on a treadmill at 5, 8, and 10 m/s before and 6 weeks after combined staphylectomy and laryngotomy. Pharyngeal and tracheal inspiratory and expiratory pressure were measured by use of transnasal tracheal and pharyngeal side hole catheters connected to differential pressure transducers. A pneumotachograph mounted on the rostral end of an airtight face mask was used to measure airflow. Results - Upper airway and translaryngeal inspiratory impedances were higher, respiratory rate was decreased, and inspiratory time was longer (P < 0.05) at all speeds after staphylectomy and laryngotomy. Conclusion - Combined staphylectomy and laryngotomy significantly affects upper airway mechanics in clinically normal horses. Clinical Relevance - Because combined staphylectomy and laryngotomy exerts a potentially adverse effect on upper airway mechanics in clinically normal horses, the procedure should only be performed when it is clearly indicated.