Accuracy of overnight pulse oximetry in diagnosing moderate to severe obstructive sleep apnoea

Multichannel sleep study is currently the gold standard for the diagnosis of obstructive sleep apnoea (OSA), but many centres in the United Kingdom still use overnight pulse oximetry as the first line investigation for diagnosis of OSA despite contradictory results in previous studies. We therefore performed this study to determine the accuracy of overnight oximetry in diagnosing moderate to severe OSA. Method and Results In this retrospective study we analysed the results of multichannel sleep studies of 89 patients with moderate to severe sleep apnoea based on Apnoea-hypopnoea Index (AHI) of 15 and above. These sleep studies were performed at Sandwell General Hospital between 1st October 2014 and 30th September 2015. Mean AHI score was 43.04 and mean Oxygen Desaturation Index (ODI) score was 27.45. Of these 89 patients, 18 were found to have an ODI score of less than 10 thus excluding the diagnosis of moderate to severe sleep apnoea. This result shows that if multichannel sleep studies were not used, 20% of patients with moderate to severe obstructive sleep apnoea could have been missed. Conclusion Our study shows that using overnight pulse oximetry alone would result in 1 in 5 patients with moderate to severe OSA being missed therefore supporting the use of multichannel sleep studies for investigation of patients with suspected OSA.