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Trying to Understand EPap, IPap & RS
#11
(05-19-2014, 06:53 AM)BiBob Wrote: I have a Oximeter that clips onto my finger but I assume you're referring to something that plug into my s9. Is that correct?
I'll look it up on the internet.


No, I merely meant an Oximeter which you can wear while you sleep and records data. If it does not record data then it cannot let you know what happened while you were asleep.

Only one very expensive model can be plugged into the S9 machine using an adapter. I think the price is as low as $1,250 if bought on Internet. If your doctor gives you a prescription for that model and your insurance covers it, great. If not, more economical options exist, such as ones sold by supplier 19. (A link to our Supplier List is at top of all forum pages.)

In the morning you would use free software which comes with the Oximeter to view the data.

Most people have the more economical type where the whole unit clips on your finger and slightly pinches on the finger. That usually works fine for most folks, and if the unit slips off before much data is recorded, it may help to use tape along the sides to help keep the unit from slipping off, but do NOT let the tape cause the unit to press on your finger any tighter, not at all. Not at all. The tape would go along the open sides, just to stabilize the unit.

I think the manufacturers conservatively recommend not wearing for longer than about 4 hrs at a time, so if it wakes me up I would either switch fingers or just take it off.

My skin is very sensitive to pressure, so I bought the kind that has a separate cup which goes on the finger tip. And I wear it on my little finger so the pressure is lightest.

Whatever type you have, I suggest wearing it perhaps one night a month, or for a night or two on different fingers whenever changing medications.

--- Vaughn


Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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#12
(05-19-2014, 07:20 AM)Bama Rambler Wrote: When the machine sees what it thinks is an event beginning, it raises the EPap slowly until it senses that it has effectively stopped the event(s) or it reaches the max IPap (22cmH2O).

Hi Bama Rambler,

If the machine does not have a backup respiration rate such as an "ST" or "ASV" type of machine, the machine will wait for the event to end before making any pressure adjustment.

--- Vaughn

Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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#13
Interesting, If that's the case then it could potentially allow every event through. If it ramped up after the event and then had time to ramp back down before the next event.
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#14
(05-19-2014, 01:16 PM)vsheline Wrote: the machine will wait for the event to end before making any pressure adjustment.

That's why I suppose it seems to take awhile for the pressure to change. If several events are back-to-back (for example, 3-4 central apneas), I sure wish the machine would react faster instead of continuing to analyze the events. That sure would be a great setting-option: REACTION-TIME (milliseconds).

Which Ox did you end up buying that has that suction cup?

This was an outstanding explanation too! THANKS! I'll store that and read it 20 times.
(05-19-2014, 02:59 AM)vsheline Wrote: At the tail end of an overnight titration, after an adequate pressure has been identified which largely prevents apneas and hypopneas, the technician may explore the effect of increasing PS in order to further reduce Respiratory Effort-Related Arousal (RERA) events, which are arousals from sleep caused by respiratory effort but not accompanied by apneas or hypopneas. The number of RERA events per hr is not included in the AHI.

Sometimes excessive daytime sleepiness continues to be a problem even after the AHI with CPAP treatment looks fine, and sometimes RERAs may be the reason; RERAs may be preventing deep restorative sleep, and increasing the PS may help this.

But too high of a PS can also cause problems, so higher PS is not necessarily better and for some patients may lead to excessive Central Apneas (more than 5 per hr and outnumbering obstructive events).

I don't think central apneas are more alarming than obstructive apneas. (I think a central event if shorter would be preferable to a longer obstructive event.)

The PS will also have an influence on your blood Oxigen level (SpO2). If the SpO2 is too low or too high it can cause problems.

So I recommend buying a recording Pulse Oximeter. A great target range for SpO2 is 96% to 94%, or perhaps a little lower while sleeping. If the average SpO2 is below 90%, increasing the PS will tend to raise SpO2. If the average PS is above 96%, decreasing PS will tend to lower SpO2.

Take care,
--- Vaughn

Sleep Apnea has given me a terrible memory. Please forgive me if I've repeated myself.
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#15
(05-19-2014, 05:47 PM)WakeUpTime Wrote:
(05-19-2014, 01:16 PM)vsheline Wrote: the machine will wait for the event to end before making any pressure adjustment.

That's why I suppose it seems to take awhile for the pressure to change. If several events are back-to-back (for example, 3-4 central apneas), I sure wish the machine would react faster instead of continuing to analyze the events. That sure would be a great setting-option: REACTION-TIME (milliseconds).

Unless the machine has a back up respiration rate such as an "ST" or "ASV" model, by design the machine does not respond to central apneas. Increasing EPAP is usually not helpful and may be harmful if central apneas are occurring.

During central or obstructive events ST and ASV units will keep EPAP fixed and will increase PS (in other words will increase IPAP) in order to do for us the work of breathing. This can be annoying at first and takes a little getting used to. For example, on my old model S9 VPAP Adapt machine (which has an ASV mode which automatically adjusts PS) if I pause to swallow, the machine will immediately increase PS very high to get me breathing again, but happily the PS returns back to normal very quickly after I have finished swallowing and am breathing normally again.

I am not sure exactly how the newer S9 VPAP Adapt machine (manufactured after October 2012) which uses a new ASVauto mode (which automatically adjusts both EPAP and PS) would respond to a swallow.

(05-19-2014, 05:47 PM)WakeUpTime Wrote: Which Ox did you end up buying that has that suction cup?

The exact model is no longer sold by Supplier 19. If I were to buy one today I would probably get the new version of the CMS-50F. The new version of CMS-50F is not (yet) compatible with SleepyHead but I find it pretty easy to eyeball results in separate programs.

The website says the old version of the CMS-50F is compatible with SleepyHead, but before buying the old version I would recommend double checking that claim, by starting a new thread "Is old version of CMS-50F Pulse Oximeter compatible with SleepyHead?"

Take care,
--- Vaughn


Membership in the Advisory Member group should not be understood as in any way implying medical expertise or qualification for advising Sleep Apnea patients concerning their treatment. The Advisory Member group provides advice and suggestions to Apnea Board administrators and staff on matters concerning Apnea Board operation and administrative policies - not on matters concerning treatment for Sleep Apnea. I think it is now too late to change the name of the group but I think Voting Member group would perhaps have been a more descriptive name for the group.
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#16
Just to finish up for the time being, I set up at IPap = 22, EPap =14 with PS = 2 last night and got AHi = 8.2 for 5+ hours. I'll leave this for a few nights to see if it's consistent. In addition, I feel really rested this morning.

This has been a very good discussion and I appreciate everyone's participation.

Thanks, Bob
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#17
(05-19-2014, 03:19 PM)Bama Rambler Wrote: Interesting, If that's the case then it could potentially allow every event through. If it ramped up after the event and then had time to ramp back down before the next event.
This is why it is important that the minimum pressure be set pretty close to your titrated pressure. The closer the min pressure is to what you need, the less time it takes to ramp up when you do start having events.

On a Resmed VPAP in Auto mode, it's important that the min EPAP be close to what you need to control the OAs and that the PS is high enough so that the min IPAP = min EPAP + PS is close to what you need to control the Hs.

On a PR Series 60 System One BiPAP in Auto mode, it's important that the min EPAP be close to what you need to control the OAs and that the min PS is high enough so that the min IPAP = min EPAP + min PS is close to what you need to control the Hs.
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#18
(05-19-2014, 05:47 PM)WakeUpTime Wrote:
(05-19-2014, 01:16 PM)vsheline Wrote: the machine will wait for the event to end before making any pressure adjustment.

That's why I suppose it seems to take awhile for the pressure to change. If several events are back-to-back (for example, 3-4 central apneas), I sure wish the machine would react faster instead of continuing to analyze the events. That sure would be a great setting-option: REACTION-TIME (milliseconds).
Actually that would NOT be a very good idea.

As vsheline writes: Plain old APAPs and plain old VPAP/BiPAP Autos are designed to NOT respond to CAs by cranking up the pressure because increased pressure may lead to MORE of the unstable breathing pattern (CO2 overshoot/undershoot cycles) that is the root cause of central sleep apnea. To treat central sleep apnea you need a machine that is designed to act as a noninvasive ventilator and trigger breaths when the breathing exhibits signs of a developing CO2 overshoot/undershoot cycle.

The way an ASV or a bilevel ST machine in T mode triggers breaths is by keeping the EPAP fixed (at a relatively low pressure for the person) and ramping up the IPAP pretty drastically (so the PS is increased rapidly) and then cycling between a low EPAP and a high IPAP. This is enough to help support the minute ventilation numbers and aid in the CO2 exchange even when the patient is demonstrating weak respiratory effort. But T mode and ASV mode are not easy to get used to sleeping with AND they require a very careful titration from a well trained tech AND those machines are very expensive.
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#19
(05-19-2014, 05:47 PM)WakeUpTime Wrote:
(05-19-2014, 01:16 PM)vsheline Wrote: the machine will wait for the event to end before making any pressure adjustment.

That's why I suppose it seems to take awhile for the pressure to change. If several events are back-to-back (for example, 3-4 central apneas), I sure wish the machine would react faster instead of continuing to analyze the events. That sure would be a great setting-option: REACTION-TIME (milliseconds).
Let's assume that WakeUpTime meant to say obstructive apneas instead of central apneas.

It's still not a good idea to have the machine instantly respond to each and every event in terms of milliseconds.

Here's why: It can take the breathing a few minutes to stabilize once an appropriate pressure is reached. And increasing the pressure too much in too short of a period of time can, counter intuitively, lead to a situation where the breathing never really stabilizes. And that can set off a nasty positive feedback loop where
  • --> more pressure --> less stable breathing --> more scoring of events and flow limitations --> more pressure --> less stable breathing --> more scoring of events and flow limitations --> more pressure -->
And pretty soon you're sitting at maximum pressure and the breathing is still not stable.

There's a reason why the manual titration guidelines for the AASM tell the tech to wait five minutes after each pressure increase before increasing the pressure again, regardless of whether there's an additional obstructive event or two during that five minute waiting period: The tech is waiting to see if the breathing stabilizes an the events stop. If they do, then there's no good reason to keep increasing the pressure. If not, the tech increases the pressure by 1 or 2 cm and then waits again to see if the breathing stabilizes.

Likewise, the manual titration guidelines for the AASM tell the tech to ignore isolated events: In order to increase the pressure the tech needs to see two obstructive events that happen pretty close together (like within about 5 minutes of each other). Isolated obstructive events are ignored.

The AUTO algorithms are designed to mimic this part of the manual titration algorithm by NOT responding to isolated OAs and Hs AND by waiting at least a few seconds to a minute or so AFTER increasing the pressure to see if the breathing stabilizes.
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#20
So, if my sleep test indicated that a pressure of 18 cmH2O was required to eliminate most OAs, I should set my min EPap close to that. If that's true Instead of 14 I should set min EPap at 15 or 16 with max IPap at 22 and RS at 2. That way when events are sensed, the difference in pressure required to minimize OAs is less than when I've set min EPap at 14 and therefore quicker.

Is this correct?
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