A recently published study investigated whether home pulse oximetry monitoring might be a useful initial screening method of determining which children with Down syndrome—who are at high risk of obstructive sleep apnea (OSA)—be recommended to undergo multichannel sleep studies to diagnose the condition. The study is published in Archives of Disease in Childhood. The home monitoring was conducted using Masimo SET Measure-through Motion and Low Perfusion pulse oximetry.
Noting that OSA “can only be reliably diagnosed using multichannel sleep studies, which are expensive, demanding for families and only available in specialist centres,” Catherine M. Hill, BM, MSc, PhD, MRCP, FRCPCH, ES, and colleagues at the University of Southampton and Southampton Children’s Hospital sought to determine whether home pulse oximetry monitoring could identify children at high risk of OSA, and in particular which parameters could most sensitively detect this risk, as an initial screening step. To that end, they studied 161 children with Down syndrome, aged 0.5 to 6 years, of whom 25 were separately diagnosed with OSA. The patients were monitored overnight using Masimo Radical-7 Pulse CO-Oximeters (pictured), with pulse oximetry sensors placed on the big toe. Recorded measurements included: total artifact-free time analyzed, mean oxygen saturation (SpO2), minimum SpO2, 3% oxyhemoglobin desaturation index (ODI), delta 12s index (the absolute difference between successive 12 second interval recordings, a measure of baseline SpO2 variability) and the number of minutes per hour that SpO2 was below 90%.
Receiver operating curves (ROC) and area under the curve (AUC) statistics were calculated to determine which measurements, alone and in combination, best predicted OSA status. During data analysis, researchers were blinded to which children had separately received a diagnosis of OSA. The researchers found that “the greatest AUC was achieved by the delta 12s index. At a threshold of >0.555, this identified 23/25 (sensitivity 92%) OSA cases and 89/136 true negatives (specificity 65%). The same sensitivity was achieved for 3% ODI with marginally lower specificity of 63% (86/136 true negatives).” The combined model (delta 12s index, 3% ODI, mean and minimum SpO2) detected all true positives (100% sensitivity) but with lower specificity (53%). This result would lead 60% of the sample population (12 true positives and 18 false negatives) to confirmatory multichannel studies.
The researchers concluded that “universal screening for OSA in children with DS [Down Syndrome] using simple pulse oximetry parameters could halve the number of children requiring specialist multichannel studies. Pulse oximetry is widely available, well tolerated, readily acquired in the home and its adoption could reduce the burden on health services and families alike.”
The researchers noted that “our findings specifically apply to parameters generated by Masimo oximeters and cannot be generalised to other devices. Masimo technology extracts motion artefact, this is important in children with DS who are restless sleepers.” They also noted that “the use of a retrospective clinical dataset, with anonymous data shared for this analysis, limits our information on the wider sampling frame, demographic and clinical characteristics of these children.”
Masimo pulse oximetry is not cleared in the United States to screen children with Down syndrome for risk of obstructive sleep apnea.