WRISTOX 2 is a reliable tool to diagnose obstructive sleep apnoea syndrome.

INTRODUCTION: Overnight pulse oximetry is an alternative to polysomnography (PSG) in diagnosing obstructive sleep apnoea syndrome, but its sensitivity is reported to be low.

AIMS: To determine the (a) diagnostic accuracy, interobserver reliability and reliable oxygen desaturation index of 4% (ODI4 ) score at diagnosing obstructive sleep apnoea syndrome in children and (b) correlation between the apnoea hypopnoea index (AHI) with ODI4 and oxygen nadir between both PSG and oximetry.

METHODS: This cross-sectional study included children aged 1-18 years old, undergoing a fully attended overnight PSG for suspected obstructive sleep apnoea syndrome. The Nonin 3150 WristOx2 ™ [Fig. 2] was worn simultaneously during the PSG. Poor oximetry recordings were excluded. Pulse oximetry was scored using the McGill Oximetry Score (MOS) whereby a score of 2-4 was positive for OSAS. Specificity, sensitivity, positive predictive values (PPV), negative predictive values (NPV) and interobserver reliability of the WristOx2 were calculated.

RESULTS: One hundred and sixty-two children with a mean (SD) age of 9.3 (±3.5) years (range 2 years 6 months old - 17 years old) were included after excluding 18 children (poor oximetry data [n = 16] and incomplete PSG [n = 2]). Interobserver agreement of the WristOx2 was 0.8763 (95% CI:0.80, 0.95). WristOx2 had a sensitivity 50%, specificity 96.7%, PPV 96% and NPV 53% at diagnosing OSAS. ODI4 ≥ 2 events/hour in oximetry had a sensitivity of 97.6% and negative predictive value of 85.7% at diagnosing OSA.

CONCLUSION: Overnight pulse oximetry with the Nonin 3150 WristOx2 ™ is an accurate and reliable tool in diagnosing significant OSAS in children.