UPPER AIRWAY COLLAPSIBILITY IN CHILDREN WITH OBSTRUCTIVE SLEEP-APNEA SYNDROME

In adults, the critical nasal pressure (Pcrit) at which the upper airw ay collapses is higher in patients with the obstructive sleep apnea sy ndrome (OSAS) than in those with primary snoring. Pediatric OSAS diffe rs clinically from adult OSAS. We therefore compared Pcrit between pre pubertal children with OSAS and primary snoring. Pcrit was determined by correlating the maximal inspiratory airflow with the level of posit ive or negative nasal pressure applied via a nasal mask. As in adults, we found that the maximal inspiratory airflow varied in proportion to the upstream (nasal) rather than the downstream (esophageal) pressure changes. Pcrit was 1 +/- 3 cmH(2)O in OSAS compared with -20 +/- 9 cm H(2)O in primary snorers (P < 0.002). In three OSAS patients reevaluat ed after tonsillectomy and adenoidectomy, Pcrit declined to -7.2 +/- 4 .0 cmH(2)O. We conclude that the pediatric airway behaved as predicted by the Starling resistor model and that Pcrit, a measure of airway co llapsibility, correlated with the degree of upper airway obstruction a nd was reduced postoperatively, consistent with increased upper airway stability.