P21 Prevalence of OSA in preoperative patients and its impact on sleep services

Introduction Screening for Obstructive Sleep Apnoea (OSA) in preoperative patients is becoming routine practice following recent guidelines published by the Centre for Perioperative care in August 2023. The aim of this audit was to review the incidental finding of OSA in the preoperative population, consider its impact on the sleep service in the trust and to re-evaluate the pathway for potential treatment of these patients.Method A retrospective audit of all preoperative patients referred between February and August 2024 was conducted. These patients had a STOP BANG score of 5 or above and were referred for overnight oximetry for OSA screening. The data analysed for the study was Oxygen Desaturation Index (ODI) to grade severity of OSA, Epworth Sleepiness Score (ESS) and Body Mass Index (BMI). 10 patients were excluded as they did not provide an ESS score.Results 174 (123 male, 41 female) were reviewed. 77.5% of patients referred had OSA according to AASM guidelines (American Academy of Sleep Medicine. AASM Manual for the Scoring Sleep and Associated Events 2007). 22.5% patients had a negative study. The mean ESS score was 6/24 over all grades of severity indicating that a significant number of the patients had no excessive daytime sleepiness. The mean ESS in the severe group was the lowest with a mean ESS of 5.1/24. ( Table 1)Abstract P21 Table 1Conclusion Preoperative screening for OSA is useful as 77.5% of patients referred had a degree of OSA. Neither ESS data or having a BMI in the obese range predict presence or severity of OSA therefore it is difficult to predict which patients are likely to have moderate or severe OSA without performing a diagnostic study.The numbers of patients found to have OSA following preoperative screening has an impact on the sleep service. Prior to this study pre-operative patients with an ODI of 10 or above were referred to sleep clinic for potential treatment. Following this audit referral to sleep clinic was prioritised to patients who pose a higher surgical risk.