Abstract

To determine whether airway receptors are responsible for the rapid, shallow breathing pattern seen in hypercapnic chronic obstructive lung disease, 10 patients underwent upper airway anaesthesia with inhaled lignocaine in a placebo controlled study. There was a significant reduction in breathing frequency after lignocaine (p less than 0.001) that was due to an increase in expiratory time (p less than 0.001). The inspiratory time remained unchanged, but tidal volume increased significantly (p less than 0.02). It is concluded that, while airway receptors may have a role in determining the frequency of breathing in chronic obstructive lung disease, other factors are responsible for the reduced inspiratory time.