Using S9 Adapt? What's your max PS?

[bemused]

Hi,
Question just for those using the S9 Vpap Adapt. What is your Max Pressure Support set at?

No, I am not changing my settings (epap 9, min PS 3.2, max PS 8 ) but curious as ResMed datasheet recommends Max PS of at least 10 and I note when I have apnea (~zero flow rate) pressure goes to 17 (max) but tidal volume continues to drop unabated until apnea ends, the Adapt pressure cycles (9-17) where each missing breath would be but does not appear to ventilate at all.

Just curious, I'll discuss with RT next week when we review results on S9 Adapt and move on to PR S1 AVAPS for two week comparison.

[Newbie Woman]

My max is set at 15 but the machine will override that if it thinks I'm in trouble.

[jamiswolf]

Hi Bemused,
I've used a Respironics asv machine and find them extremely complex to set up and to understand what's actually happening.

PS philosophy is changing over time. Used to be 3 or 4 cmh20 was the norm. Now it's common to see up to 10cmh20 ps.

So what you're saying is that you can see in the waveform data that your central apneas are not being treated by the machine?

Is there an absolute pressure setting on that machine and what is yours set at?

Curious...
J

[bemused]

Sorry, jamiswolf i missed your reply.

Re absolute pressure setting. The S9 Adapt only has 3 settings (yes, it does cost $6,000): epap setting (4-20), minPS (3-6), maxPS (8-16). That's it! no timing, epr or anything else, it is all automatic. The PS ramps up during an event cycling each breath to increase ventilation.

My epap was 9, minPS 3, maxPS 8, so ipap can range from 12-17 depending on what the machine determines is required (epap does not change). My question was because when I look at the data during an event the pressure is maxing out at 18cm soon after the start of an event and not seeming to make much impact.

Resmed recommend maxPS should be 10 or more, but my RT obviously disagrees. I'm wondering if we are stifling the machine's ability to use whatever is needed to control events but I can find almost nothing on the web to back this up. Machine has the capability of going up to 25cm but will NOT override maxPS setting entered by clinician. She has now increased epap to 10 because we think some events may still be obstructive, but maxPS remains at 8 (the lowest possible setting) so machine can go to 18, no more.

Vpap Adapt is designed to treat Central and Complex Apneas, but very little info on how it does it. It is VERY comfortable to use, though.

Hi Bemused,
I've used a Respironics asv machine and find them extremely complex to set up and to understand what's actually happening.

PS philosophy is changing over time. Used to be 3 or 4 cmh20 was the norm. Now it's common to see up to 10cmh20 ps.

So what you're saying is that you can see in the waveform data that your central apneas are not being treated by the machine?

Is there an absolute pressure setting on that machine and what is yours set at?

Curious...
J

[Newbie Woman]

I'm the newbie, not the expert, but your settings are confusing to me. Why would your exhalation pressure be higher than your max pressure?

[LittleRedTruck]

My S9 adapt is set to Epap is 8, min PS is 3 and max PS is15. In looking at Resscan I frequently ramp to 23 Ipap knock down periodic breathing or a central. My AHI is usually less than 1. Good luck ! Dan

[JohnBFisher]

Hi,
Question just for those using the S9 Vpap Adapt. What is your Max Pressure Support set at?

No, I am not changing my settings (epap 9, min PS 3.2, max PS 8 ) but curious as ResMed datasheet recommends Max PS of at least 10 and I note when I have apnea (~zero flow rate) pressure goes to 17 (max) but tidal volume continues to drop unabated until apnea ends, the Adapt pressure cycles (9-17) where each missing breath would be but does not appear to ventilate at all.

Just curious, I'll discuss with RT next week when we review results on S9 Adapt and move on to PR S1 AVAPS for two week comparison.

Greetings! The recommended max PS depends on your diagnosis. For example, if you "only" have central sleep apnea, then having a max PS of 15 would be fine. But if you have Complex Sleep Apnea Syndrome (ComplexSAS), then it is possible during your titration study they discovered that going above an iPAP of 17 would cause more central apneas. If that was the case, then the max PS would be set to 8 (epap + max ps = max IPAP), which would limit the maximum pressure to 17cm H2O.

So, the amount of pressure you need depends on your specific needs ... not on the general recommendations from the manufacturer.

Hope that helps.

[JohnBFisher]

I'm the newbie, not the expert, but your settings are confusing to me. Why would your exhalation pressure be higher than your max pressure?

Greetings! Here's how (n general) the ASV units work:

The EPAP is the lowest pressure the machine will use during exhale. The actual IPAP value depends on the amount of pressure the machine thinks you need to (a) keep your airway open and (b) to sustain breathing when you have a central apnea. To do this, it has a Pressure Support range that is added to the EPAP value to obtain the IPAP. So, if you are breathing well (no delays, no shallow breathing, no central apneas), then the machine would deliver an IPAP that is equal to EPAP plus the min PS value. So, if your EPAP is 10 and your min PS is 4, then you min IPAP would be 14. However, if you are having problems (due to slowing breath rate or a central apnea), the machine will quickly swing toward the maximum IPAP value. This is obtained by adding max PS to EPAP. If the max PS is 15 and the EPAP is 10, then the max IPAP would be 25. And the Resmed machines will reach this pressure usually within three breaths. Talk about rapid pressure swings!

So, we if have the following settings

EPAP = 10
min PS = 4
max PS = 15

We end up with the following:

EPAP = 10
min IPAP = 14
max IPAP = 25

Hope that helps explain how the pressure support works on most ASV units. The Respironics units have a variable EPAP (a min EPAP and a max EPAP) as well as a lot of other settings to tweak. So, they can be a lot more "interesting".

[jamiswolf]

Hi Bemused,
Thanks for the response to my post. I'm way over my head regarding your machine. I've seen lots of people have difficulty with the high pressure bursts...treating centrals. So limiting PS might make the machine easier to tolerate.

I use a BiPap ST which uses fairly low pulses to "trigger" a patient breath. It seems to work well...at least with me. Isn't that also what asv machines do? Or do they actually provide enough pressure to essentially breath for you? That's been a source of confusion for me when trying to understand people using ASVs and having 30cm max pressure.

I think it's cool that they're letting you try out the Respironics machine and then choosing between the two. The Respironics has a manual BPM setting which you may need to try if PTBs are low on auto. Keep us posted...
j

[bemused]

My question exactly, jamiswolf! I am also trying to understand how the asv works, it appears it can ventilate (that does mean it forces you to breathe, right?) Resmed says PS of 15 will ventilate a 'normal healthy' patient. However I suspect it also 'trains' me how to breathe. johnBfisher, insightful, you may be right about the titration.

This is a close up of an event last night, I thought the ramp up in pressure would persuade me to breathe but tidal volume (and flow rate) stay down until the event ends. I don't yet understand enough to know if this is as it should be, or not.

[bemused]

oops, didn't get the image right, 2nd try:

[JohnBFisher]

My question exactly, jamiswolf! I am also trying to understand how the asv works, it appears it can ventilate (that does mean it forces you to breathe, right?) Resmed says PS of 15 will ventilate a 'normal healthy' patient. However I suspect it also 'trains' me how to breathe. johnBfisher, insightful, you may be right about the titration.

This is a close up of an event last night, I thought the ramp up in pressure would persuade me to breathe but tidal volume (and flow rate) stay down until the event ends. I don't yet understand enough to know if this is as it should be, or not.

I will take a stab at the answer in your other thread.

[JohnBFisher]

By the way, I never answered your first question. I have two units. One is Resmed. The other is Respironics. My max PS is 15 on both, with an EPAP of 10. So my IPAP is 25cm H2O. A bit 'windy', wouldn't you agree?