Bi-pap AVS better for treating UARS?

[dsm]

A brief update: My sleep lab date finally arrived last night! And it could not happen soon enough. Despite using my CPAP religiuously the past months, I have felt pretty worn out.

The sleep lab set me up with a Fisher & Paykell Flexifit 432 full mask. Never used a full mask before. It was surprisingly comfortable. They did a split test, with a few hours of Bi-pap followed by several hours of SV. The bi-pap did not go well. Slept very unsoundly and felt I was fighting the machine. My inhalation breaths kept getting cut short by the sudden switch over. The sleep tech had to do numerous adjustments. I simply could not adjust to it. It was the abrupt switch between IPAP & EPAP and back again. It felt very unnatural and disrupted my breathing patterns.

The SV, on the other hand, felt great! Slept straight through for 4+ hours. The breathing felt very natural.

Anyway, just wanted to capture my experience while its fresh. I will update with the official report later.

Gobears

Glad to hear this has worked out well.

I have done a lot more research re UARS since the earlier posts & what is very clear is that UARS is a 'spectrum' of respiratory situations all related to upper airway resistance but some with quite different causes. Some UARS conditions are considered unrelated to OSA (if OSA is not present). But other UARS types can be and fit into the flow limitation definition of OSA. The damage from all forms of UARS really relates to how much effort a person has to put into sucking air in & what damage that effort can do over time esp if the person has other health issues (overweight etc: ).

Re the bilevel not working well for you. I had this experience where Bipap models (Pro II, S/T, Auto(Biflex)), would constantly switch too early from Ipap to epap & it got to be very disconcerting. The 1st Bipap that seemed very tolerant was the Bipap AutoSV. Over time I did tests with other brands of bilevel & didn't get that early switching. In time I was able to satisfy myself that my problem was restricted airflow through my nose which seems to upset the Auto Trak software in the earlier AutoTrak based Bipaps. If I tried a Bipap that was developed before AutoTrak, it worked normally at the ipap/epap switch despite my restricted nasal breathing.

My doc has had me on Nasonex for the past 18 months but I now am finally going to see an ENT to look at possible ways of getting more air through my nostrils (if I hold nares open, get lots of air & it feels very easy to breathe).

Even with my current ASV machines, if I have a congested nose & try nose breathing, the Vpap AdaptSV in particular will start ramping up the pressure very quickly even though I can't breath any more air due to the restricted airflow - so I have just learned to mouth breathe & the machine goes right back to normal cycling.

ASV really does do its best if the type of UARS experienced is not due to physically restricted airflow as it is pretty obvious that upping the pressure with that type of UARS restriction will not get more air in & thus leads to an arousal when the pressure has gone high enough. UARS triggered by GERD or other such conditions can behave differently in this situation (have GERD as well so do experience both situations).

But, again, it seems ASV offers a better approach for your situation.

Hope it continues well

DSM

[gobears]

With regards to the Bi-Pap problem, I experienced both of the situations described by Kiralynx and DSM: My inhalation breaths were cut short by the sudden shift from IPAP to EPAP, AND the machine was cycling at its own rate, sometimes faster and sometimes slower. I felt I had to try and time my breathing to match it. Not much fun. Again, when ASV was switched on, the problems disappeared. BTW, this was a pretty new sleep lab with top of the line equipment (unfortunately, I did not notice the model). Glad to hear that I was not a special case, that others have also experienced the problem.

DSM,
I also had nasal flow restrictions. I had a deviated septum, which was fixed in November, along with turbinate reduction. Definitely improved matters, but I can honestly say it was disappointing. I still have much higher flow through one side than the other. Still, i think it helped the effectiveness of the therapy.

In any event, I will have a direct comparison very soon when the sleep test results are released. I will update everyone on the results. Also, my sleep doctor is up to speed on UARS, so I will quiz him about it when I see him (I too have been digging into UARS). UARS is very confusing, as some skew it towards thin people with low blood pressure (I don't fit that description).

[-SWS]

Congratulations on finding what sounds like a better treatment platform, Gobears! I look forward to hearing more details about the sleep study and your upcoming experiences with ASV.

Thanks for reporting in.

[Overflow]

I am happy to further qualify my prior comments by adding that I believe SV is ideal for UARS. If the sleeper is experiencing OSA events & little else, then cpap or bilevel will & should work for them.

If the sleeper is prone to centrals, hypopneas & flow-lims (read UARS), then any device that can detect a flagging volume within 1 breath, and can re target volume within that breath and can adjust pressure instantaneously in an attempt to maintain the target volume,that device has to be beneficial - unless!, the sleeper has some disorder that dictates only gentle pressure rises (COPD patients may need to be careful in the set up of an SV machine).

There are other considerations that come into how effective SV might for particular people (build & lung capacity etc: etc:) but the discussion really gets too specific & becomes a distraction.

The most important thing about SV is that it may be no good for people who are purely OSA sufferers (typically with solid builds & large necks). As mentioned before, if the sleeper is having a typical OSA event above the epap pressure, an SV won't know it is OSA as it works on the principle that epap is dealing with no-flow events and the machine will assume it needs to boost pressure rapidly to maintain target volume.

In future versions of SVs they may add more tests to determine if an apnea experienced above the epap pressure is a no-flow blockage (i.e. by using FOT bursts or some other probing technique). Then based on such a determination, suspend the SV algorithm but perhaps raise epap (I have seen a patent that appears to do this). But today, from what I understand of the technologies available on the market, this type of extension to SV is still experimental.

DSM

#2 Added this link where the authors say they can achieve a high level of accuracy determininga CSA vs OSA events using FOT (goes back to the late 1990s)
http://ieeexplore.ieee.org/Xplore/login ... pdf?temp=x

Sorry to dig up such an old post. But is this still true? I am primarily diagnosed OSA with little central activity on an APAP (maybe 5-20 a night sometimes) but am trying ASV to see if it offers greater comfort.

Are these machines less effective for OSA than APAP or Bipap though?

I am not sure exactly what this means from s1 AutoSV FAQ as well:

Does the BiPAP autoSV operate like an Auto CPAP or Auto Bi-level device for treating obstructive events?

No – The device does not have an auto-titrating algorithm to alleviate obstructive events. The innovative algorithm was designed to treat complex apnea and periodic breathing. The obstructive component of SDB is treated utilizing a clinician adjustable CPAP or BiPAP pressure level.

Essentially, is the machine is worse at auto targeting pressure for OSA events? (from http://www.healthcare.philips.com/main/ ... sv/faq.wpd)