P049 A retrospective review of predictors of hypoventilation measured via transcutaneous carbon dioxide monitoring on diagnostic sleep studies

Abstract Background Sleep related hypoventilation is deadly, complex to diagnose and very treatable. It is caused by medical comorbidities, such as obesity, opiate medications and rare neuromuscular conditions. Transcutaneous carbon dioxide monitoring during polysomnography is the gold standard to diagnose sleep related hypoventilation. There is currently no strong evidence base for when to do transcutaneous carbon dioxide monitoring. The aim of the study is to identify which baseline clinical measures are most accurate at identifying nocturnal hypoventilation. Methods This study will review the results of 200 adult, type 1 polysomnograms which included transcutaneous carbon dioxide monitoring from the year 2024 at a single, tertiary institution. All CPAP and NIV titration studies will be excluded. Data collection will include patient demographics of age, gender, the presence of hypoventilation and 14 clinical predictors, including known aetiologies/comorbidities, awake oxygen saturation, BMI and previous history of or awake hypercapnoea. Progress to Date This project is currently in the data collection phase. Intended outcome and impact Logistic regression will be used to identify the clinical measures most predictive of hypoventilation, evaluating individual and combined measures for accuracy. As sleep services shift to increasing home-based diagnostics, which cannot diagnose hypoventilation, it is important that this diagnosis is not missed. Thus, this study is important to help identify those patients in the clinic at highest risk of hypoventilation, to ensure that this diagnosis is detected.