Site and mechanics of spontaneous, sleep-associated obstructive apnea in infants

To examine the mechanics of infantile obstructive sleep apnea (OSA), airway pressures were measured using a triple-lumen catheter in 19 infants (age 1 -36 wk), with concurrent overnight polysomnography. Catheter placement was guided by correlations between measurements of magnetic resonance images an d body weight of 70 infants. The level of spontaneous obstruction was palat al in 52% and retroglossal in 48% of all events. Palatal obstruction predom inated in infants treated for OSA (80% of events), compared with 38.6% from infants with infrequent events (P = 0.02). During obstructive events, succ essive respiratory efforts increased in amplitude (mean intrathoracic press ures -11.4, -15.0, and -20.4 cmH(2)O; ANOVA, P < 0.05), with arousal after only 29% of the obstructive and mixed apneas. The soft palate is commonly i nvolved in the upper airway obstruction of infants suffering OSA. Postterm, infant responses to upper airway obstruction are intermediate between thos e of preterm infants and older children, with infrequent termination by aro usal but no persisting "upper airway resistance" and respiratory efforts ex ceeding baseline during the event.