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

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.