Tracheal dynamics in infants with respiratory distress, stridor, and collapsing trachea.

The purpose of this investigation was to evaluate the tracheal “collapse” commonly seen during roentgenoscopy of newborn and older infants. It was hoped this would lead to a better understanding of the mechanism of changes in lumen dimensions and their relation to “tracheomalacia,” stridor, and respiratory distress. While the trachea and bronchi normally dilate on inspiration and narrow on expiration, they are also observed to “collapse” on cough and the Valsalva and similar maneuvers. Measurements of the bronchial and tracheal diameters in normal subjects have emphasized the wide range of variation (1–3). Prior to cineroentgenography, observations of luminal changes were made under conditions which in themselves influence these changes by adding airway resistance, as through a bronchoscope or other intraluminal hardware. No such factors were brought into practice in our observations other than the introduction of one to one and a half cubic centimeters of bronchographic contrast media into the trachea In...