Aircurve BiPap stops while inhaling

[jmagic]

Hello Apneaboard,

today my Aircurve 10 ST arrived and I tried to adjust it a bit and to get used to it while looking a film. In comparison with pure CPAP fixed on one number, it is really more comfortable and feels more like breathing. But there is one little problem and I hope its because of my bad settings.

While on CPAP mode the pressure is always constant and I dont have exhale inhale interruptions. But when I'm on BiPAP 10/6 and I'm Inhaling and the machine stops at the shortly end before I finished inhaling and this makes a little interruption in my breath. It bothers me a lot because it's somehow unnatural and destroys the great relief which BiPAP gives. Is it always like that or something about the settings? Can't the machine wait until im finished inhaling? I read the manual and some posts about them, but until now I was not able to tweak this problem.

I set Timax a bit higher to have more time to inhale, I Inhale and exhale very slowly.

Thanks in advance for every answer!

Best regards,
Jasmin

[Sleeprider]

Jasmin, I'd be interested to see your Oscar chart with the flow rate, mask pressure and inspiration time included so we can see what is normal for you, as well as what's out there at the 95%-99% Insp time. You are using a relatively slow rise time of 900 ms and a TiMax of 4.0, so I don't think you're running into that. The ST produces a square wave pressure support rather than using Easybreathe, so you may be sensing the plateau of pressure support, rather than the unit actually cycling back to EPAP. If you are looking at your Oscar charts, using the above graphs, look for the peak of mask pressure and any indication that your inspiratory flow-rate rise gets stalled during the flat peak of IPAP. If so, you may be looking to fine-tune the rise time to be even longer, and perhaps using a bit more PS.

[jmagic]

Hello Sleeprider,

fist of all thank you very much that you take time for me. I do not take for granted! I think I understood what you wanted to say with "plateau of pressure support" the PS ends abrupt and that is the feeling what I get on that. I wanted to counteract that feeling with a Rise time of 900ms and Tmax of 4sec. Actually it is more comfortable with this settings, but as you explained they do not really interfere with my problem.

You suggested to make the rise time longer and to increase the PS. The rise time is already at it's max 900ms or do you mean the other way? I will try to increase the PS. Actually the PS will be very important for me, because I tend to UARS and flow limitations. But when Pressure support is higher than 4-5 the extreme change in from (e.g. 6-11) makes the mask bouncing and you can not really sleep with it. Do you actually know what i mean with that?   My xPap terminology and level of English is a bit ristricted to express myself like on German.

PS: This was just a test to get used to the machine. I will have my first night tonight, so Im trying now to get the best tweaks.

Thanks again for your professional help!

Best Regards,
Jasmin

[Sleeprider]

The problem is, you could use the Aircurve 10 S or Vauto and have the Easybreathe™ pressure shape. It feels more natural.  The choice of ST was not ideal for you, and perhaps you can find someone willing to trade that actually needs the timed backup feature of the ST.  Because of the square-wave pressure support delivery on the ST, I don't think there is any way to resolve the feeling of PS cutting out.   Your chart is an excellent example of the problem with square-wave pressure support (you can make it more clear by adding a dotted line at 0.0 of the flow-rate). Your inspiration flow accelerates nearly immediately to a peak flow around 45 mL/sec then flattens and actually decreases slightly until exhale begins.  With either the S or Vauto, the pressure support continues to come in behind your spontaneous effort and the peak mask pressure comes at the same time as your peak inspiration effort. With the ST,  your respiratory flow is a mirror of the mask pressure, and there is very little we can do about that. 

Looking closer at your respiratory statistics we see an unusually very high tidal volume combines with a very slow respiration rate to produce a moderately high minute vent. These respiratory statistics are very unusual and I would be interested to know what they are with CPAP or without enabling the unusually long inspiration times with a long rise time, long Ti Max and very low Cycle setting.  I realize you came to those setting because you felt your breathing was being cut-off, but assuming you have otherwise healthy pulmonary function, you have achieved a very unusual respiratory pattern with hyperinflation and slow respiration. This hyperinflation is very undesirable and can lead to lowered heart function and other problems.  I really think we should pursue a more normal volume and rate for you, whatever that may be.  I think we should start by reviewing why you are on a ST bilevel machine, the results from your diagnostic study (respiratory rate and volume) and any past use of CPAP that might have had more normal respiratory function. Unless there is an underlying health issue, I would like to see what your respiration looks like when using machine settings closer to default values with 0.04 Ti Min, Ti Max 2.5-3.0, Rise time 300 ms and cycle sensitivity Medium.




For comparison, here is an example from my machine.  Note my respiration rate is closer to what might be ocnsidered normal to slightly fast, but my tidal volume and minute vent remain relatively high, but not freakishly high as yours.

[jmagic]

Hello Sleeprider,

you explained the difference between the flow rate and mask pressure in comparison with your results very very very well. Even as a newbie I know what is the kind of problem now. To be honest I aimed to buy an Aircurve 10 S on the used market (ebay). Unfortunately they just had the Aircurve 10 ST model. I researched a bit and I thought "Hey. You can switch to CPAP and S mode without problem. It should have the same functionalities like the both".

So I bought the ST model and switched to the S-Mode without really knowing, that it is not containing the Easy-Breathe modus. Are you using Easy-Breathe? And even without the Easy-Breathe mode at a normal Aircurve 10 S, is this square wave pressure support just a Aircurve 10 ST thing? I have a ritual before I go to sleep. Before I go to sleep i slow down my inhale and exhale speed to fall into sleep a kind of meditation technique. I wasn't really able to to this with the square pressure support and I felt I was constantly fighting against it, altough the lower pressure at exhaling (BiPap) was much more comfortable in comparison with a CPAP mode. But I dont have  a real flow in it.

I try to sleep today with the CPAP mode to see how my natural breathing patterns are to share it here and to analyze it. I think I have a normal respiratory function (I hope at least). That was a classical case of "do not buy things before you know everything about it". But I did not really have assistance and I thought "Aircurve 10 ST" switchting on the S-mode will serve me with all the features a Aicurve S will have. I think I have to wait until something is available on the used market and sell my Aircurve 10 ST one.

Beside my gratefulness for your professional input. Merry Christmas (If you celebrate).

Best Regards,
Jasmin

[jmagic]

I found a used ResMed S9 VPAP S. Do you think it would do the job as well despite not having the Easy-Breath mode?

Sorry for spaming.

[SarcasticDave94]

Given the situation, I think probably VAuto will serve you best. But I'm wondering if modifying Trigger and/or Cycle may help out till you can get a better suited replacement.

Trigger would modify how the machine transitions from EPAP to IPAP, while Cycle modifies transitions from IPAP to EPAP.

[jmagic]

Hello Saracasticdave,

I think a VAUTO 10 version is not affordable for me. I can aim for a Aircurve S 10 normal or a S9 VPAP S. Do you think the older generation would do it also without a problem?

Thank you and Merry Xmas!

Best Regards,
Jasmin

[SarcasticDave94]

9 series would be just fine for you, I think. I would try getting one with as low of hours as possible.

[Sleeprider]

You can make that ST work, but you have to deal with the square-wave pressure and allow the machine to cycle normally by removing the long rise time, long Ti Max and very low cycle sensitivity. Even if it is less comfortable, your respiration should normalize in rate and volume.

The S9 VPAP S has Easybreathe and it can but turned on or off as an option.  Feel free to request the clinical manual from the link at the top of the forum.  It will describe the available functions and how Easybreathe works.  

I hope what I posted above was helpful.  It was just painful looking at how artificial and contorted your respiration has become with the current settings.  My Vauto and all of the Airsense 10 CPAPs have Easybreathe.  Here is an image from the clinical manual.  As you can see the only VPAP without Easy-Breathe is the ST.