W. Stipp, R. Musgrave, S.R. Williams, B. Segal-Epstein, I. Ebrahim, L. Shenkman,
Oxitone Medical LTD, Kfar Saba, Israel, Divity Health, London, UK, Optima Health, Sheffield, UK, The London Sleep Centre, London, UK.
Introduction
This study tested the hypothesis that wrist-based oximetry was able to perform as well as finger-based oximetry in detecting desaturation events
Materials and Methods
Diagnostic tests were performed on a consecutive series of 10 patients who presented at the London Sleep Centre for investigation into potential OSA. Participants wore the Oxitone device on their wrist, at the same time as undergoing a standard Home Sleep Apnoea Test (Philips Alice Night One) scored by a skilled physiologist as part of their routine care. Desaturation indices of both 3% and 4% were compared between both the wrist-based oximeter and fingertip-based oximetry. Patients provided feedback on comfort sleeping with the wrist sensor device as expressed on a Likert scale.
Results
We found a strong Spearman correlation of 0.75 (p<0,001); the limits of agreement with the Bland-Altman test were <10 and the two-tailed Mann-Whitney U test showed no significant difference between the indices from the two devices (p>0.05). There were no reports of patient discomfort with the screening process.
Conclusions
These results indicate that wrist-sensor oximetry may be used instead of finger-based oximetry in screening for OSA. A screening protocol for OSA is suggested in populations without significant cardiorespiratory or neurological disease, no severe insomnia and no significant side-effects medication. A suitable application in occupational health is to screen for OSA in vocational drivers or safety critical worker populations. The protocol is based on a symptom questionnaire of suspected OSA (UK NICE guidance on Obstructive Sleep Apnoea Syndrome, Nov 2021) and a 3% ODI of 5 or more. Cases with negative oximetry and negative symptom questionnaire responses would not require referral to a sleep center for an OSA diagnostic assessment. Cases still require referral to a sleep center for an OSA diagnostic assessment if only oximetry, or only the OSA symptom questionnaire are positive. Cases with positive OSA questionnaire responses, a 3% ODI of five or more and oximetry with a sawtooth appearance (manual affirmation), is highly specific for an OSA diagnosis. Individual sleep centres may initiate a trial of OSA therapy in such moderate to severe cases. The wrist sensor oximeter is likely to improve ease and patient compliance of future OSA screening programmes.
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