Evaluation of the upper respiratory tract in the horse during treadmill exercise - A review Part ll: Measurement of upper airway flow mechanics

Abstract

Literature pertaining to the evaluation of the upper respiratory tract of the horse during exercise was reviewed. Articles were found by searching two databases. Videoendoscopy of the upper airways during exercise is presented in part I of this review. Part II describes upper airway pressure and airflow measurements for objective assessement of the prescence of a respiratory limitation. Different measurement techniques and definitions of upper airway pressure as well as airflow measurement techniques are described. Upper airway pressures and flow indices increase linearly with increasing exercise. Airflow resistance as caused by laryngeal hemiplegia grade IV increases negative upper airway pressure and limits inspiratory flow. Dorsal displacement of the soft palate alters both inspiratory and expiratory pressures.