ST vs ASV - studies about risk

[SarcasticDave94]

Dave the thread drift was put into a thread you started here: http://www.apneaboard.com/forums/Thread-...ed-5-15-17
This conversation was occurring in a therapy thread by Larryrapp and it just seemed like it should be on its own.

OK copy. Not disputing actions or any such. I was attempting to make note of possible split in case kiwii had interest in referring to both. I just hadn't found the second thread yet. I just didn't convey my full thought the first time around, so my apology if I muddied the waters.

[kiwii]

Thank you for the heads-up on the thread split, and for the link.

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Yes! The split contains the exact part that was elusive! THANKS!

[paulag1955]

What is ST?

[kiwii]

This page on the wiki explains the different machines:

http://www.apneaboard.com/wiki/index.php...ure_(BPAP)


The way the pulmonologist explained it (to me), is the machine will give air at set times, assuming that you are not breathing on your own.

[kiwii]

What is it that determines whether someone would be prescribed with an ST vs. an ASV?

I know a bunch of people here have gone on to use ASV, and it is newer technology. My situation sounds (to me) somewhat similar to HalfAsleep, although mine is not anywhere near as severe.

[paulag1955]

Kiwii, thanks for the link and the short explanation.

[SarcasticDave94]

ST stands for Spontaneous Timed. It refers to a machine that has a backup rate for breathing, which is performing a forced breath ventilation. It can typically be used for patients that have COPD or other breathing restrictions, and can include the COPD and Sleep Apnea overlap syndrome.

ST: remember T is for timed. There is a timed breath rate setting that tells the machine the patient will breathe x times per minute, and if the patient does not do so, a breath will be forced on them. This is added onto a BiLevel machine. There's likely more about it I missed.

ASV: Adaptive Servo Ventilator, I have this one, you program in (on mine at least, and assuming it's run in ASV Auto mode) EPAP min and max and Pressure Support (PS) min and max. This is also a BiLevel machine; it has a lower expiry pressure and a higher inspiration pressure. On my ResMed, the machine uses an algorithm to determine in the EPAP range what's needed to keep the airway open while still allowing a lower exhale pressure. Upon inhale, it will go by the PS range to come up with the higher inhale/IPAP pressure. It can constantly vary between the setting ranges, per breath, to find the best combo to minimize obstructive, central, and hypopneas. To get this machine, the patient needs to pass the heart echo test for determination of congestive heart failure being present or not. And, one would have to prove medical need due to the central apnea indicated on the PSG.

[kiwii]

.. And, one would have to prove medical need due to the central apnea indicated on the PSG.

Am I correct in thinking that the ASV can also force a breath on you?

Both the pulmonologist & sleep doctor #3 said that the weird breathing thing is central apnea [if I understood them correctly], and both are suggesting a bi-level with backup. It was the sleep doctor that said I would be titrated for an ST machine; Dr P was thinking that my current machine would have a setting for backup (but it doesn't). [edit: and Dr P was looking at my SleepyHead charts; Dr #3 was looking at her own computer with my data card]

[SarcasticDave94]

yes it can and does, funny I have one and it only seems to do so, or this is only when I notice it, if I'm lying awake trying to sleep, I get mine to "back off" by the blow-back method AKA literally blow into the mask and machine backs off pressure

[paulag1955]

Dave, thank you for that excellent explanation.