0588 Sleep Below 90: A Simple Oximetric Index that Integrates Hypoxic Burden

Abstract Introduction Introduction: The Time Spent with Saturation below 90% (TS< 90%) is a marker for the severity of nocturnal hypoxemia. Objective: To evaluate the association between TS< 90%, Heart Rate (HR), Oxygen Desaturation Index (ODI), and Hypoxic Burden (HB) in patients with Obstructive Sleep Apnea (OSA). Methods Methods: This was a cross-sectional study, nested within a cohort, where 36 individuals were evaluated, 58.1% of whom were women, with a mean age of 53.95 ± 11.86 years. Patients with OSA were included, and measurements of Body Mass Index (BMI), ODI, HR, SO2, TS< 90%, and HB were collected. HB was measured using the formula considering the area under the curve of oxyhemoglobin desaturation > 3%. Results Results: The sample presented BMI 30.77 ± 8.06; ODI 19.89 ± 43.64; HB 93.07 ± 181.10; Minimum SpO₂ = 82.23 ± 11.90; Mean SpO₂ = 93.55 ± 5.73; Maximum SpO₂ = 140.14 ± 192.06; TS< 90% = 51.75 ± 124.47; Number of Hypoxemic Events 0.73 ± 2.53; Total Time in Hypoxemia 12.36 ± 48.29; Minimum HR 52.32 ± 6.95; Maximum HR 110.09 ± 11.71; ΔHR 39.73 ± 11.32. A correlation was observed between TS< 90% and: HB (r = 0.487; p = 0.022); ODI (r = 0.492; p = 0.020); Age (r = 0.027; p = 0.907), BMI (r = 0.357; p = 103); Minimum HR (r = 0.027; p = 0.906); Mean HR (r = 0.414; p = 0.056); Maximum HR (r = 0.047; p = 0.836); ΔHR (r = 0.396; p = 0.068); Minimum SpO₂ (r = 0.486; p = 0.000); Mean SpO₂ (r = 0.691; p = 0.000); Maximum SpO₂ (r = 0.098; 0.644); Number of Hypoxemic Events (r = 0.784; p = 0.000); Total Time in Hypoxemia (r = 0.650; p = 0.001). Conclusion Conclusion: In this study, TS< 90% showed a robust correlation with HB, ODI, number of desaturations, and total time in hypoxemia, in addition to being strongly associated with the drop in minimum and mean SpO₂. These findings suggest that TS< 90% can function as a simple, direct, and highly informative marker of nocturnal hypoxemia. Support (if any)