20 Validation of WatchPAT 300 for pre-operative of OSA screening in patients undergoing bariatric surgery

Introduction Undiagnosed obstructive sleep apnoea (OSA) is increasingly recognized as a serious post-operative risk with bariatric surgery, hence increasing demand for pre-operative screening and a need for simpler ways for screening than the clinical standard, respiratory polygraphy, to mitigate strain on sleep services. WatchPAT 300 (WP) is a finger-mounted sensor that uses peripheral arterial tonometry to estimate the apnoea hyponoea index (AHI). While its use is increasing it has not yet been validated in patients with a BMI >35, the target population in bariatric surgery. Aims To validate WP against polygraphy in pre-bariatric surgery patients with clinically suspected OSA and a BMI>35 and to assess patient acceptability of WP. Methods AHI was measured simultaneously with WP and Embletta. Outcome measures were 1) autoscored AHI from WP and 2) manually re-scored AHI from Embletta. Agreement between AHI from Embletta and WP was assessed using intra-class correlation coefficient (ICC), bland Altman and ROC plots. Results 28 patients (22 female/6 male, mean ± SD age 44.1 ± 11.6, BMI 45.7 ± 7.5) participated. One study failed due to the patient removing the WP probe prematurely. AHI was higher in WP than Embletta (28.1± 17.9 versus 15.0 ±13.4; p 15 (Area under the curve 0.917; p Discussion WP accurately estimates the AHI in pre bariatric surgery patients, has a low failure rate and is clinically acceptable in this group. Further larger scale studies are needed to confirm these findings before incorporating into clinical guidelines.