Relationship between Pulmonary Resistance and Changes in Arterial Blood Gas Tension in Dogs with Nasal Obstruction, and Partial Laryngeal Obstruction

Abstract

Arterial blood gas tension and pulmonary resistance were measured in dogs with surgically created (A) nasal, and (B) laryngeal obstructions. Preobstruction mean values were obtained in all parameters for normal control data. Postobstruction measurements were made, serially, over a period ranging from three days to three months. Changing the dogs from nose to mouth breathers resulted in significant adverse changes in laryngeal resistance, especially marked in the expiratory phase, decreased Po 2 and retention of Pco 2 as well as some change in pulmonary resistance. Laryngeal obstruction resulted in significant pre and postobstruction differences in pressure-flow relations in the larynx, k 1 and k 2 values and arterial hypoxemia. Results suggest some anatomic and physiologic changes occurring in the lower airway as a result of marked nasal and partial laryngeal obstruction.