Normal polysomnographic respiratory values in children and adolescents

Polysomnography is important in the evaluation of children and adolescents with sleep-disordered breathing. Adult criteria for obstructive sleep apnea have been shown to be inapplicable to children. Nevertheless, very little data are available regarding normal respiratory parameters during sleep in healthy children and adolescents. The purpose of the study was to characterize normal polysomnography values in healthy children and adolescents and to establish respiratory reference values for pediatric polysomnography.

Seventy healthy, normal children and adolescents were studied. Age ranged from 1 to 15 years (mean +/- SD, 8.02 +/- 4.57 years). All children underwent overnight polysomnography including EEG, electromyography, electrooculography, ECG, pulse oximetry arterial oxygen saturation (SpO(2)), chest wall and abdomen motion, oral and nasal airflow, and end-tidal PCO(2) (PETCO(2)).

Three children (4%) had a mean of 0.37 obstructive apneas (OAs) per hour of sleep (1 to 5 OAs per child per study), with mean apnea duration of 10.3 +/- 2.1 s. This was not accompanied with oxygen desaturation. Twenty-six children had one to seven central apneas (CAs) per child, resulting in a mean of 0.4 CAs per hour of sleep (median, 0.33; 97.5 percentile, 0.9). Eleven of the 58 events of CA in six children coincided with oxygen desaturation to a minimum of 88% (nadir apnea desaturation range, 88 to 93%). The mean SpO(2) was 97.2 +/- 0.8% with SpO(2) nadir of 94.6 +/- 2.2%. PETCO(2) > 45 mm Hg occurred for 1.6 +/- 3.8% of total sleep time (TST) in 21 of 70 children (30%), with a distribution of 1.3 +/- 3.03% in the range of 46 to 47 mm Hg; < 0.7% were within the range of 48 to 50 mm Hg; and in 0.29 +/- 0.24% of TST, PETCO(2) values were > 50 mm Hg.

Based on these data, the recommended limits for normal values are as follows: OA index, 1; CA index, 0.9; oxygen desaturation, 89%; baseline saturation, 92%; and PETCO(2) > 45 mm Hg for < 10% of TST.