A comparison of pulse oximetry and cerebral oxygenation in children with severe sleep apnea-hypopnea syndrome: a pilot study

Abstract

Near infrared spectroscopy (NIRS) has been used to assess the impact of obstructive sleep apnea-hypopnea syndrome (OSAHS) on cerebral oxygenation. However, the relationship between the variations in the cerebral tissue oxygen saturation (ΔTOI) and pulse oximetry (ΔSpO₂ ) has not been assessed in children with OSAHS. Consecutive clinically stable children with severe OSAHS [apnea-hypopnea index (AHI) >15 events h^-1 ] diagnosed during a night-time polygraphy with simultaneous recording of cerebral oxygenation with NIRS (NIRO-200NX, Hamamatsu Photonics KK) were included between September 2015 and June 2016. Maximal ΔSpO₂ (SpO₂ drop from the value preceding desaturation to nadir) and concomitant variations in transcutaneous carbon dioxide (ΔPtcCO₂ ), maximal ΔTOI and maximal variations in cerebral oxygenated (O₂ Hb) and deoxygenated (HHb) haemoglobin were reported. The relationships between ΔSpO₂ , ΔPtcCO₂ and ΔTOI, ΔO₂ Hb and ΔHHb were investigated. The data from five children (three boys, aged 9.6 ± 6.7 years, AHI 16-91 events h^-1 ) were analysed. Strong correlations were found between ΔSpO₂ and ΔTOI (r = 0.887, P < 0.001), but also with ΔO₂ Hb and ΔHHb with a particular pattern in the youngest child with a dark skin pigmentation. Mean ΔSpO₂ was 20 ± 17% and mean ΔTOI was 8 ± 7%. Maximal ΔSpO₂ of approximately 70% were coupled with ΔTOI of no more than 35%. ΔPtcCO₂ correlated only weakly with the cerebral oxygenation indexes. This pilot study shows a strong relationship between pulse oximetry and cerebral oxygenation in children with OSAHS, with lower changes in TOI compared to SpO₂ . Future studies should address the clinical impact of respiratory events on cerebral oxygenation and its consequences.

Keywords: cerebral autoregulation; children; hypoxaemia; near infrared spectroscopy; sleep-disordered breathing.