EFFECT OF COMBINED STAPHYLECTOMY AND LARYNGOTOMY ON UPPER AIRWAY MECHANICS IN CLINICALLY NORMAL HORSES

Objective-To investigate the effect of combined staphylectomy and lary ngotomy on upper airway mechanics in clinically normal horses running on a treadmill. Animals-6 Standardbreds. Procedure-Upper airway mechan ics 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 lary ngotomy. Pharyngeal and tracheal inspiratory and expiratory pressure w ere measured by use of transnasal tracheal and pharyngeal side hole ca theters connected to differential pressure transducers. A pneumotachog raph mounted on the rostral end of an airtight face mask was used to m easure airflow. Results-Upper airway and translaryngeal inspiratory im pedances were higher, respiratory rate was decreased, and inspiratory time was longer (P < 0.05) at all speeds after staphylectomy and laryn gotomy. Conclusion-Combined staphylectomy and laryngotomy significantl y affects upper airway mechanics in clinically normal horses. Clinical Relevance-Because combined staphylectomy and laryngotomy exerts a pot entially adverse effect on upper airway mechanics in clinically normal horses, the procedure should only be performed when it is clearly ind icated.