Comparison of nap and overnight polysomnography in children.

Overnight polysomnography is the "gold standard" for diagnosing sleep-disordered breathing. However, the limited number of resources for pediatric polysomnography make the availability of a screening test for sleep-disordered breathing highly desirable. Therefore, we compared 1 hour daytime nap polysomnography to overnight polysomnography in 40 children [mean age, 5.4 +/- 0.8 (SE) years] with sleep-disordered breathing; 76% of children were sedated with chloral hydrate for nap polysomnography; none was sedated for overnight polysomnography. Studies were done 26 +/- 4 days apart. Chest wall motion, ECG, end-tidal PCO2 (PETCO2), arterial oxygen saturation (SaO2), and electrooculogram were monitored. Nap studies had a sensitivity of 74%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 17% in predicting sleep-disordered breathing. Significantly more children had obstructive apnea and desaturation (SaO2 less than 90%) during overnight polysomnography. The peak PETCO2 and the SaO2 nadir were significantly worse during overnight polysomnography. However, the percentage of time during which abnormalities were manifested did not differ between nap and overnight polysomnography. Despite the use of sedation, nap polysomnography underestimated sleep-disordered breathing. We conclude that sleep-disordered breathing detected by nap polysomnography is always confirmed by overnight polysomnography and speculate that nap polysomnography may be an effective screening method for sleep-disordered breathing. However, overnight polysomnography should be performed if nap polysomnography is inconclusive. Chloral hydrate may be used effectively to facilitate sleep for nap polysomnography in children.