TcCO changes correlate with partial obstruction in children suspected of sleep disordered breathing.

Introduction: Pediatric sleep disordered breathing (SDB) is characterized by long periods of partial upper airway obstruction (UAO) with low apnea-hypopnea indices (AHI). By measuring snoring and stertor, Sonomat studies allow quantification of these periods of partial UAO.

Aim: To determine whether transcutaneous CO (TcCO ) levels correlate with increasing levels of partial UAO and to examine patterns of ΔTcCo in the transitions from (a) wakefulness to sleep and (b) non-rapid eye movement (NREM) to rapid eye movement (REM) sleep.

Methods: This was a retrospective review of sleep studies in seven asymptomatic controls aged 7 to 12 years and 62 symptomatic children with suspected SDB and no comorbidities, aged 2 to 13 years. Both groups underwent overnight polysomnography, including continuous TcCO , at one of two pediatric hospitals in Sydney. Changes in carbon dioxide levels between wake to NREM (sleep onset) and NREM to REM sleep were evaluated using an all-night TcCO trace time-linked to a hypnogram. Paired Sonomat recordings were used to quantify periods of UAO in the symptomatic group.

Results: The ΔTcCO at sleep onset was greater in SDB children than controls and ΔTcCO with sleep onset correlated with the duration of partial obstruction (r = .60; P < .0001). Children with an increase in TcCO from NREM to REM had a higher number of snoring and stertor events compared to those in whom TcCO decreased from NREM to REM (91 vs 30 events/h; P = < .0001).

Conclusions: In children without comorbidities, the measurement of TcCO during sleep correlates with indicators of partial obstruction.