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.