Age specific differences in pediatric obstructive sleep apnea.

BACKGROUND: Some have suggested that younger children have a more severe form of obstructive sleep apnea than older children and therefore are at a higher risk for respiratory compromise after tonsillectomy and adenoidectomy. However, at present there are few studies that have identified any significant correlation between age and severity of obstructive sleep apnea.

OBJECTIVE: To determine if age specific differences in obstructive sleep apnea are present in children.

DESIGN: Retrospective chart review.

SETTING: Tertiary care children's hospital.

PATIENTS: The records of children (1-18 years of age) with obstructive sleep apnea diagnosed by overnight polysomnography between January 1998 and January 2001 were reviewed. Children included in the study also had evidence of adenotonsillar hypertrophy and had no other co-existing medical problems.

MAIN OUTCOME MEASURES: Overnight polysomnography was performed in all children. Apnea-hypopnea index (AHI), baseline and lowest O(2) saturation, baseline and peak end tidal CO(2), and total number of obstructive apneas, hypopneas, central apneas and mixed apneas were measured during each polysomnogram. Children were subdivided into the following age groups: 1-2, 3-5, 6-11 and 12-18 years. Polysomnograms were classified into normal, mild, moderate and severe categories.

RESULTS: Three hundred and sixty-three children were studied; 45 children were ages 1-2 years, 159 children were ages 3-5 years, 137 children were 6-11 years and 22 children were 12-18 years. Although there appears to be a trend towards a greater mean number of obstructive apneas, hypopneas, central apneas, mixed apneas, a higher mean AHI, lower mean SaO(2) nadir, and a higher mean PETCO(2) in the younger age groups when compared to the older groups, a Student's t-test demonstrates that there is no statistical significance for most OSA parameters. An analysis of variance using the F-test reveals statistical significance (p<0.01) when children ages 1-2 were compared to those 3-5, 6-11 or 12-18 years of age for the variables AHI, mean number of central apneas, hypopneas and mixed apneas. When comparing patients in the various severity categories, children ages 1-2 years show a distinct distribution with a larger percentage in the moderate to severe categories. Chi square analysis reveals a significant difference between the frequency distribution of children in age group 1-2 years and that of the other age groups (p<0.01).

CONCLUSION: There is a predilection for children less than 3 years of age to have more severe obstructive sleep apnea as documented by polysomnography. Central apnea also appears to be more common in this age group. These findings may be explained by anatomic and physiologic differences related to age and support a period of observation following adenotonsillectomy in younger children.