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      2. I have questions about Study Management

      Hypoxic Burden

      Hypoxic Burden is an advanced metric now available on Study Management reports. Please contact your EnsoData CSE at support@ensodata.com if you would like this added to your reports.

      Clinical Relevance:

      • Based on peer-reviewed, published literature (see below), Hypoxic Burden (HB) can be used to measure the impact of hypoxemia through the duration of a sleep study.

      • HB is defined as the total area under the oxygen saturation curve from a pre-event baseline oxygen desaturation.

      • It is measured in %min/h (think: the number of percentage points the patient is desaturating multiplied the number of minutes that desaturation is sustained, divided by the hours of sleep time)

      • HB takes into account three factors:

        • Frequency of respiratory-related desaturations (how often are they happening)

        • Depth of desaturations (how low do they go)

        • Duration of desaturations (how long do they last)

      Summary of literature conclusion:

      • Higher HB is a potential indicator of poorer cardio health and can explain cardio risk better than just the AHI. A higher AHI doesn’t necessarily mean a higher HB, though the metrics are correlated.

      • HB is a potential indicator of cardiovascular disease-related morbidity and mortality in patients with OSA.

      • Please read the literature references below to determine the clinical
        relevance and implications for your patients.

      Here are a few examples of sentences we can add to your report:

        • Most basic: “The total hypoxic burden for the patient was 68.84 based on 403 desaturation events”

        • More in-depth: “The 3% hypoxic burden value calculated for this study is 68.84 %min/hr, which is in the 73rd percentile of an age- and sex-matched clinical cohort (0 is least severe, 100 is most severe). This is an advanced metric not within the AASM Scoring Manual that is based on a cohort of 11103 historical sleep studies.”

      How do I read the curve on the chart?

      Per the literature, the larger the area above the curve, the higher the HB. The chart is built by plotting the desats on top of one another. A lower and wider curve is considered more severe.

      We can see how the HB curve compares to a patient's AHI. 

      Associated literature:

      • The hypoxic burden of sleep apnoea predicts cardiovascular disease-related mortality: the Osteoporotic Fractures in Men Study and the Sleep Heart Health Study https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6451769/