hypopnea duration

[unidee]

Very good topic to discuss! My opinion is that total apnea time is good information and should be in Oscar.

I throw some questions which can be discussed. I have seen my apneas are about 10 sec long. Both CA and OA (and UA). Have all people "constant" apnea time? And is the effect of apnea dependent how long it time takes? For example 5 sec apnea is not so bad than 10 sec.

If this total apnea time is removed from Oscar, how important are Daily pages weight data? Weight is not from cpap machine. 

[pholynyk]

For Spacewrench:

* Can OSCAR accept / display heart-rate data?  (I'm working on a way to record data from a Bluetooth heart rate monitor, and I'd like to see it correlated with my respiratory data.)

* What is the resolution of the pressure data?  The UI makes it look continuous (in time and value), but that seems like it would be a lot of data!

I suspect the easiest way to display heart-rate date is to dummy up a ChoiceMed .dat file with a fixed SpO2 value. It's a fairly straight forward file format, unlike the Contec format. Remember to make sure the CPAP machine time is set correctly, because your Bluetooth connected HR monitor's clock probably is...

I'm not sure of Respironics devices, but for Resmed it is set by the edf file format at 16 bits - but you probably meant what is the sampling frequency. Resmed has two different ones; the pressure and flow are sampled at 25 Hz - 40 milliseconds between samples, and also the mask Pressure and average pressure is reported every two seconds. You can see which is which by going into Preferences/Appearence and checking Square Wave Plots - I think you have to restart OSCAR to see the change. And zoom in the time scale, of course.

[Melman]

Very good topic to discuss! My opinion is that total apnea time is good information and should be in Oscar.

I throw some questions which can be discussed. I have seen my apneas are about 10 sec long. Both CA and OA (and UA). Have all people "constant" apnea time?  No, mine vary between 10 sec and 20sec (e.g 10, 12, 14, 19)

And is the effect of apnea dependent how long it time takes? For example 5 sec apnea is not so bad than 10 sec. A longer apnea has a worse effect in that oxygen deprivation will be greater. It's like holding your breath for longer.

If this total apnea time is removed from Oscar, how important are Daily pages weight data? Weight is not from cpap machine. 

[rlchau]

Hi all,
To further complicate the issue re: OSCAR’s “Total time in apnea” calculation, may I add that one should also consider that ResMed, to only account for that supplier, does not treat an apnea as a total cessation of respiration; following their definition in their “ResCan Report Interpretation Guide” p. 78:

Apnea: The temporary absence or cessation of breathing. An apnea is scored when there is reduction in breathing by 75% of the baseline breathing for at least 10 seconds.

Don’t we have the same issue with apneas as we have with hypopneas?

Here’s how I sort of compensate or get another interpretation for those unknowns and stats: When transferring/interpreting my data in the morning, I check my “Total time in apnea” and then, I often make a point to verify, among other things, if my obstructive apneas are partial or complete (if you allow me to use that terminology). How I do this: I check each of my “obstructive” events, look at the corresponding “inspiration time”, “expiration time” and “tidal volume” and I pay attention to the 0.0 value.  As an example, I had a superb evening last night of AHI 4.0 (this is very good for me… according to my standards L).  I had 8 obstructive apneas and only three of them had a 0.0 value for a few seconds. My stats: 8 obstructive apneas for a total of 178 seconds (ResMed/Oscar total); 3 out of those 8 totalled 95 seconds within which I was in total apnea (0.0 value) for 24 seconds only overall. So 24/178 (13 %) of total apnea in the OSA category.

[A KLERK]

Maybe what we want to know is how much breath (i.e. air or oxygen) is missed. In the time before an apnea, we can calculate from the flow data how much air is inhaled and exhaled 'normally'. Then when an apnea (obstructive or central) occurs, an estimate can be calculated of what amount of air is missed. And knowing that some 20% of the air is oxygen, we would know how much oxygen is lacking...
That also goes for a Hypo. Although there is shallow breathing, still something is missed.
But then comes the hardest point: over what time should we calculate that deficiency? How fast will the desaturation have an effect? One thing is for sure: clusters of (hypo-) and apneas short after each other will have more effect than when those are evenly spread over the night.

For that, the programmers have to find nice calculation ways and that will only come after all the shortcomings in the spaghetti-software are repaired. At the moment they are busy parsing many 'new' information bits from the raw data.