Should children with suspected obstructive sleep apnea syndrome and normal nap sleep studies have overnight sleep studies?
OBJECTIVE
Overnight polysomnography (ONP) is the "gold standard" for the diagnosis of sleep-disordered breathing, but it is expensive and time-consuming. Thus, daytime nap studies have been used as screening tests. If the findings of a nap study are normal or mildly abnormal, should ONP be performed? Do specific abnormalities in nap studies predict abnormal findings in ONP? To answer these questions, we conducted this study.


METHODS
Retrospective chart review.


METHODS
Children's hospital.


METHODS
One hundred forty-three children with suspected obstructive sleep apnea syndrome secondary to isolated adenotonsillar hypertrophy, who had normal or mildly abnormal nap studies, and underwent ONP.


RESULTS
We compared daytime nap and overnight polysomnograms in 143 children (52 girls; mean [+/- SD] age, 5.6 +/- 3.1 years). Total sleep time was 1 h in daytime nap, and 5.1 +/- 1.3 h in ONP. The interval between the two studies was 5.9 +/- 4.8 months. The findings of 59% of the nap studies were mildly abnormal, while 66% of overnight studies were abnormal. No individual nap study parameter (including short obstructive apneas, hypopneas, hypoxemia, hypoventilation, snoring, paradoxical breathing, gasping, retractions) had good sensitivity at predicting abnormal overnight polysomnograms, but most had good specificity and positive predictive value.


CONCLUSIONS
We conclude that individual nap study parameters are not very sensitive in predicting abnormal ONP findings. However, when nap study parameters are abnormal, the chance of obstructive sleep apnea syndrome is high.
Division of Pediatric Pulmonology, Mattel Children's Hospital, University of California at Los Angeles School of Medicine, USA.
M M
MM
Saeed
T G
TG
Keens
M W
MW
Stabile
J
J
Bolokowicz
S L
SL
Davidson Ward
D001944:Breath Tests; D002245:Carbon Dioxide / Q000032:analysis; D002675:Child, Preschool; D002940:Circadian Rhythm; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D010100:Oxygen / Q000032:analysis; D017286:Polysomnography / Q000379:methods*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000175:diagnosis* / Q000503:physiopathology; D012893:Sleep Wake Disorders / Q000175:diagnosis* / Q000503:physiopathology
D002245:Carbon Dioxide; D010100:Oxygen