Recovery of airway patency after obstruction in normal infants.

We examined the characteristics of spontaneous restoration of airflow after airway obstruction during neck flexion in normal sleeping infants. In 22 of 27 episodes of complete airway obstruction in 5 of 8 infants, there was some resumption of airflow, although the angle of neck flexion was maintained. The airway reopening was usually delayed, after 1 to 3 obstructed inspiratory efforts, and usually without evidence of behavioral arousal. The time course of this delayed response suggested chemoreceptor mediation. In those trials where arousal was observed, airflow resumed immediately. Our observations suggested that activation of the genioglossus and other airway-maintaining muscles leads to airway reopening neck flexion in infants and that tonic genioglossus activity maintains airway patency. These observations represented the first description of restoration of airway patency after airway occlusion in infants.