Polysomnography
Children underwent PSG at an accredited sleep laboratory as part of clinically indicated care. PSG tests were performed in technical accordance with standards proposed by the American Academy of Sleep Medicine (AASM), by registered polysomnography technicians. Electroencephalogram (placement of frontal [F3,F4], central [C3,C4], occipital [O1,O2] electrodes referenced to the opposite mastoid electrodes [M1,M2]), electro-oculogram, electromyogram (chin and both legs), electrocardiogram, pressure transducer and thermistor airflow, uncalibrated respiratory inductance plethysmography, oximetry, and end-tidal CO2 (ETCO2) data with video monitoring of the study for scoring support was collected. All studies were scored by a pediatric pulmonologist board certified in sleep medicine, in accordance with pediatric scoring rules proposed by the AASM16. In our institute, post-sigh central apneas are not scored.
Standard PSG collects a number of variables as a multi-parametric test to evaluate and diagnose sleep disorders. PSG data collected included: date of study, age at time of study, percentage of sleep spent in REM, sleep efficiency, Oxygen Desaturation Index (ODI), Arousal Index (AI), Apnea Hypopnea Index (AHI), Central Apnea Index (CAI), Mixed Apnea Index (MAI), Obstructive Apnea Index (OAI), Hypopnea Index (HI), Central Apnea Hypopnea Index (CAHI), average pulse rate, Total Periodic Limb Movement Index, average oxygen saturations in wake vs. sleep, nadir saturations in sleep, total duration of desaturations, total sleep time spent between 45 and 49 mmHg ETCO2, total sleep time spent greater than 50 mmHg ETCO2, average ETCO2 during sleep, and peak ETCO2during sleep.