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New approach diagnosing Apnea

Dear All,

I am researching for an issue on apnea cases.

My question is: Is that possible to diagnose apnea basically from the SaO2- SpO2 values only ? By this, we will figure out if there are reasonable results and make people more comfortable to get apnea treatment from their houses, especially whom are disabled.

I use the polysomnography .edf raw values, filter Time-SaO2 with EDF browser and import to MS SQL.

In MS SQL I run a query code and calculate the oxygen desaturation during all time which is appoximately 8,5 hours for each, around 30.000 secs.

I focus on the AHI and RDI basically. As I know shortly, RDI = AHI + Arousals .

When I compare the real study results ( lets consider shhs1-200041_filtered_data ), non-apnea results generally match but existing-apnea results and my own results do not seem mathcing.

I wonder, is the approach has something to add, modify or change ? Can I get some reasonable and undestandable results with this methodology.

Beside, I can share the sql query code and results if anyone wants ?

I really appreciate to hear from experts as you.

Regards

Omer

In addition, image and text does not match with the nssrid and edf files. Please refer to image. you can considershhs1-200001_filtered_data, shhs1-200002_filtered_data and shhs1-200003_filtered_data.

Thanks in advance

Omer,

The RDI* variables in SHHS are not necessarily "AHI + arousals". They are more like AHI variables, but all events (apneas and hypopneas) are required to be associated with a desaturation (of 4%, for instance, in RDI4P).

I assume there are people trying to "diagnose" sleep apnea using only an oximetry channel. Naturally, the ODI closely aligns with AHI in many cases.

Do you have any specific data questions? Or inconsistent data findings? I wasn't sure exactly what I was looking at in your image.

Note that if you derived "new" oxygen desaturations from the raw signal then you would want to be sure your methodology matched with whatever was used by the original sleep scoring software. Otherwise your new metrics would not be comparable.

Mike

Hi Mike, Following up on this discussion, how do we know what AASM guidelines were used for scoring on the different databases? Also, in addition to the AHI/RDI entries, is there a ''final diagnosis'' from the MD that is provided? (and which is based on both indexes and symptoms as per the ICSD-3)?

Thanks, Joachim

The scoring manuals should describe the scoring procedures for different datasets, e.g.

• SHHS Manual of Procedures
• MESA Polysomnography Scoring Manual

There isn't a "final diagnosis" per se since the sleep studies for most datasets were conducted for research purposes, so there wasn't an MD interpretation at the end. Users could try computing their own diagnosis variable from the indexes of interest and questionnaire data.

Thanks Mike. That's helpful. Although as I look at the SHHS information it does not look for any of the regular AASM rules for the hypopnea events scoring (AASM mentions desaturations of 3 or 4 % depending on the guideline year, whereas on the SHHS Manual they mention 2% desaturations).

Joachim,

Sleep Heart Health Studies were collected prior to AASM rules and do not follow the standard AASM guidelines for hypopnea scoring. Please refer to the manual referenced above for respiratory event scoring procedures.

Best,

Stephanie

Hi Stephanie, Thanks for the clarification,

Best, Joachim