Upper airway obstruction in canine laryngeal paralysis.

The type and the severity of airway obstruction in 30 dogs with bilateral laryngeal paralysis was assessed, using tidal breathing flow-volume loop (TBFVL) analysis. The dogs had clinical evidence of mild-to-severe upper airway obstruction (ie, respiratory distress, exercise intolerance, stridor). Seventeen dogs had TBFVL consistent with a nonfixed (inspiratory) obstruction, 10 had TBFVL indicative of a fixed (inspiratory/expiratory) obstruction, and 3 had normal TBFVL. Analysis of TBFVL confirmed that dogs with laryngeal paralysis have upper airway obstruction that differs in type and severity. Use of TBFVL provided a quantitative evaluation of airway obstruction and demonstrated the effects of bilateral laryngeal paralysis on the breathing patterns of dogs.