TcCO₂ changes correlate with partial obstruction in children suspected of sleep disordered breathing

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.

To determine whether transcutaneous CO₂ (TcCO₂ ) levels correlate with increasing levels of partial UAO and to examine patterns of ΔTcCo₂ in the transitions from (a) wakefulness to sleep and (b) non-rapid eye movement (NREM) to rapid eye movement (REM) sleep.

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 TcCO₂ , 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 TcCO₂ trace time-linked to a hypnogram. Paired Sonomat recordings were used to quantify periods of UAO in the symptomatic group.

The ΔTcCO₂ at sleep onset was greater in SDB children than controls and ΔTcCO₂ with sleep onset correlated with the duration of partial obstruction (r = .60; P < .0001). Children with an increase in TcCO₂ from NREM to REM had a higher number of snoring and stertor events compared to those in whom TcCO₂ decreased from NREM to REM (91 vs 30 events/h; P = < .0001).

In children without comorbidities, the measurement of TcCO₂ during sleep correlates with indicators of partial obstruction.