resmed S9 autoset sleep report question

[Daso]

Sorry if this has been asked before but I couldn't find any thread with answer. When looking at your nights sleep report, does the AHI reported on the S9 compare to the home sleep study report which originally gave me an ahi of 6. Is the resmed result anywhere near as reliable as a sleep test or just for comparison to itself? My sleep apnea report said I have an AHI of 6, when on cpap, the resmed unit report shows I'm between 0.1 - 0.6 depending on night. Thanks.

[TyroneShoes]

Your sleep test sees the same data that an xPAP does; it just records a lot more types of data along with it (hence the forest of wires and pads). They probably also both record these events with about the same level of accuracy, because that is not a difficult task. But for both, AHI is the same, and is calculated the same, except that the xPAP does not know when you are asleep so counts the entire time the blower is on whether you are asleep or not, while a sleep study has the ability to constrict reporting to when you are actually asleep, so there can be a bit of discrepancy there.

You will also find that many things can affect AHI, and that it is different night to night. It is not an exact number, and for the data to really make sense, you have to average it out over a few weeks and look for trends. Also, conditions during a sleep study are quite different than conditions when you are sleeping in your own bed. So the value of the small sample of the data from a single sleep study for a few hours in a foreign environment is in question when compared to parsing data from weeks on end in the exact environment you sleep in every night.

You also can't expect to compare apples and oranges; your APAP titrates pressure dynamically according to an algorithm that is supposed to mimic what a trained human operator would do to keep your AHI as low as possible throughout the night as conditions change. But in a titration sleep study, the operator pushes the boundaries of pressure to see what works best for you, and has just a few hours to accomplish that, which means that they have to push the boundaries in ways that increase your number of events, so that they can validate what moving away from those boundaries can do to create fewer events. Consequently, a titration study can easily show a higher AHI simply because the approach is different than what a well-tuned APAP is doing.

A sleep study is great for an initial diagnosis or for determining if there are neurological factors in one's sleep issues other than the normal things that an xPAP can treat, and it is good for titrating pressure. But looking at the data for every night at home also has value, and while that data is more limited, it is still the same data and over time can be considered more accurate because the sample is so much larger; both are tools that can help us, and in slightly different ways.

My S9 worked fine for 4 months, then reported a different AHI than SleepyHead (which parses the same data) for a few nights in a row. But a full power cycle rebooted the microprocessor and got it back on track. Other than that, I think the xPAP data is pretty dependable.

[DeepBreathing]

Daso, I assume the home sleep study was not using a CPAP machine? In that case, the AHI of 6 is the untreated result. The numbers reported by the machine are the treated result. If you're consistently getting 0.1 to 0.6 it shows the machine is doing its job and lowering your AHI to an acceptable level.

[Daso]

Daso, I assume the home sleep study was not using a CPAP machine? In that case, the AHI of 6 is the untreated result. The numbers reported by the machine are the treated result. If you're consistently getting 0.1 to 0.6 it shows the machine is doing its job and lowering your AHI to an acceptable level.

Thank you both for your responses. Deepbreathing , You are correct. My AHI of 6 was from a home sleep study without using CPAP. My AHI reading from last night on the S9 was .5 and 0 leak rate at a pressure of 5.5

[BigEars]

Your AHI will be different every night. Mine is.