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BiPAP Pressure in the morning
#11
RE: BiPAP Pressure in the morning
(12-04-2013, 07:19 PM)apdtap Wrote: Thank you for all the reply. But I believe the machines can detect "apnea" or "blocked air way", hence if I am awake and breathing nomally, the "top line" machines shoud be smart enough to reduce the presure as my aire way is not blocked. If the machines cannot even detect this, I wonder how good those "auto" or "bi-level" machines are over the "basic auto" CPAP. I will be seeing my doctor again in Jan but I hope to get more of your feedback too. Thany you again.

Not all apneas are caused by a blocked airway. Central apneas occur when the message from your brain stem to your diaphragm is interrupted. In other words, nothing is telling your body to breathe. In this case your airway could be wide open, but you're not getting any air.

The better machines can detect the difference between an obstructive (blocked airway) and central (open airway) apnea. ASV type machines are designed to treat centrals. It often happens that new users experience central apneas which they didn't before, and these usually resolve as your body gets used to the new way of breathing. Centrals can also occur as you transition into and out of sleep. Importantly, any pause in breathing that lasts longer than 10 seconds is registered as a central apnea - and this can happen even while you're awake.

If you're on a bilevel or ASV machine, it will be for a specific reason, such as central apneas occurring during your sleep study, or a straight CPAP or auto machine not being able to treat your apnea sufficiently. I wouldn't be too quick to dismiss the high-end machine until you take these other factors into consideration.
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#12
RE: BiPAP Pressure in the morning
Thanks for all the good answers. I have only been using the machines for a few days. The high pressure in the morning is only annoying as I have to turn off anyway. Just thought the high end machines can respond faster. Will keep you guys posted.
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#13
RE: BiPAP Pressure in the morning
(12-05-2013, 12:02 AM)apdtap Wrote: Thanks for the reply. My main point is whether those high end machines can find the best EPAP IPAP quickly. I will try and inform after a few more days. My experience in the morning so far is that they cannot?
I think that you have some major misconceptions about how the Auto algorithms for Auto Bi-level machines work.

First and formost: Plain old auto bi-level PAP machines are NOT ventilators. They do NOT try to force you to breath during the middle of an apnea. (There are PAP machines that can act as non-invasive ventilators----they are the bi-level ST machines, the ASV machines, and the AVAPS machines. But the plain old Resmed S9 VPAP Auto and the PR System One BiPAP Auto do NOT have a "T" mode and cannot try to trigger an inhalation when you stop breathing.)

Second: These machines do NOT "quickly" find "the best" EPAP or IPAP pressure. Rather, their auto algorithms are designed to raise the pressure response to events after the events happen. They typically raise the IPAP/EPAP pressures somewhere between 1 and 4 or 5 cm over a period of time that might be as short as 30 seconds or so (under some circumstances for the Resmed S9) to as long as 5 or 6 minutes (for the PR System One.) Moreover, once they raise the pressure, they do NOT quickly lower the pressure back down to the minimum settings. Moreover, auto bi-level PAP machines do not necessarily raise the pressures after every single apnea: Rather, they adjust the pressures after the end of a cluster of two or more events in order to prevent more events from happening. And the machine will start to lower the pressures only after the machine is happy with the shape of the wave flow (i.e. the machine thinks you are breathing satisfactorily.) And once the machine starts to lower the IPAP/EPAP pressures, it will lower them in a gradual fashion over the course of several minutes. (The S9 will typically start lowering the pressures sooner, but it will take longer to lower them all the way back to "baseline".)

Third: These machines also raise the pressures in response to snoring and flow limitations. Both machines respond pretty aggressively to snoring and flow limitations since these are thought to be precursors to a potentially collapsing airway. And the idea is to provide more air pressure before the airway actually collapses. A flow limitation is defined as a change in the shape of the inspiration part of the wave flow---the trace of the air flow into and out of your lungs with each and every breath you take. Certain changes in the shape of the inspiration part of the wave flow are thought to indicate that the airway is just barely beginning to collapse. The airflow is not yet restricted enough to count as a hypopnea and nowhere near restricted enough to count as an apnea, but because the airway might be beginning to collapse, the machines increase the pressure to make it harder for the airway to collapse enough to cause a real hypopnea or a real apnea.

Fourth: The machines' apnea, hypopnea, and flow limitation algorithms are based on the premise that the person attached to the machine is likely asleep. And normal sleep breathing is usually much more regular and quite a bit more shallow than normal wake breathing. When we are awake, we take the occasional deep cleansing breath (or even a series of them). We may consciously slow our breathing down as a way to relax ourselves. We may take a super deep, long breath preparing to sigh. We'll temporarily hold our breath while concentrating on something----sometimes it's something as simple as turning over in bed with a six foot hose attached to our nose. And we may not even be aware that we're momentarily holding our breath for several seconds while we're awake. The point is this: Normal wake breathing patterns are often irregular enough to fool APAPs into thinking that we're exhibiting signs of sleep disordered breathing because the breathing pattern does NOT resemble normal sleep breathing patterns. It's not uncommon, for example, for a full efficacy data machine to record some "false" events as your breathing settles down from deep, irregular wake breathing right after putting on the mask to shallower, slower breathing as you try to relax enough to go to sleep. If the air flow on those shallower breathes is 30-40% less than the series of DEEP inhalations right after you put the mask on, the machine may very well score a hypopnea or two. And if it scores a pair of closely spaced events while you are settling down in bed? The machine's auto algorithm will kick in and increase the pressure because of the cluster of two events.

Finally: The PR BiPAP Auto has an algorithm that proactively tests increases of IPAP pressure during the night to see if a small increase in IPAP pressure will lead to a better shape in the inspiration part of the wave flow pattern. If the increase in IPAP pressure does improve the shape of the wave flow, then a new, higher "base line" IPAP pressure setting is established. If the machine increases the IPAP (or the IPAP and EPAP) in response to some combination of hypopneas, apneas, flow limitations, snoring, and RERAs, after the machine is happy enough with the shape of the wave flow it will then first start testing small decreases in pressure down to the last "baseline" IPAP pressure. If any deterioration in the shape of the wave flow is detected, the IPAP pressure increased back up to the current setting. What this means is that the PR System One BiPAP can be very reluctant to reduce the IPAP pressure all the way back down to the minimum IPAP pressure setting during the night. You really have to look at what's driving the increase in IPAP pressure to understand when or whether the System One will manage to decrease the IPAP all the way back down to the minimum IPAP setting.

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#14
RE: BiPAP Pressure in the morning
(12-04-2013, 07:19 PM)apdtap Wrote: Thank you for all the reply. But I believe the machines can detect "apnea" or "blocked air way", hence if I am awake and breathing nomally, the "top line" machines shoud be smart enough to reduce the presure as my aire way is not blocked. If the machines cannot even detect this, I wonder how good those "auto" or "bi-level" machines are over the "basic auto" CPAP.

A lot of people wonder that, too, but not for the reason you're stating.

These machines have a pressure sensor and a low-inertia flow meter. That's all. Using some rather clever techniques programmers have been able to distinguish between an open airway apnea and a closed airway apnea. They send pressure pulses and measure changes in the resulting flow rate. And they do other things, too. But they haven't figured out a reliable way to determine if you're awake. They are rather reliable at adjusting the pressure for most people, though.
Sleepster

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#15
RE: BiPAP Pressure in the morning
Hello all: Now after about 3 weeks, I do not feel the high mask pressure after waking up in the morning. My ResMed AutoSet still reads usually just less than 10 (my prescription is 14). If the machine is "clever" enough, it should still reduce the pressure to "none". My respirologist thinks this is irrelevant as I should take off my mask and swicth off the machine anyway. I still cannot cannot get Sleepyhead to display all my data properly and ResScan to read my SD card at all. Next month, I hope to try machine with software included so that I can get more info.
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#16
RE: BiPAP Pressure in the morning
(12-20-2013, 09:59 PM)apdtap Wrote: Hello all: Now after about 3 weeks, I do not feel the high mask pressure after waking up in the morning. My ResMed AutoSet still reads usually just less than 10 (my prescription is 14). If the machine is "clever" enough, it should still reduce the pressure to "none". My respirologist thinks this is irrelevant as I should take off my mask and swicth off the machine anyway. I still cannot cannot get Sleepyhead to display all my data properly and ResScan to read my SD card at all. Next month, I hope to try machine with software included so that I can get more info.

Maybe it is because I am tired, but I don't really understand what you are trying to say. And, I don't understand what you say your RT thinks. For me, and maybe others, it would be helpful if you update your profile to include the information of the machine and mask you are currently using.
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#17
RE: BiPAP Pressure in the morning
(12-20-2013, 09:59 PM)apdtap Wrote: Hello all:


Howdy! Dancing

Quote:Now after about 3 weeks, I do not feel the high mask pressure after waking up in the morning.

That sounds pretty normal. Humans are good at adapting to our environment. After a while the CPAP machine feels like a part of the nightly routine.

Quote:My ResMed AutoSet still reads usually just less than 10 (my prescription is 14). If the machine is "clever" enough, it should still reduce the pressure to "none".

Not so. 4 cm is the minimum pressure. Auto CPAP machines are programmed to respond to apneas and flow limitations, but they will need to raise the pressure to the appropriate level to do so.

If the machine stayed at the minimum pressure that would be an indicator that you likely don't have OSA.

Quote:My respirologist thinks this is irrelevant as I should take off my mask and swicth off the machine anyway.

Huhh?!

Quote:I still cannot cannot get Sleepyhead to display all my data properly and ResScan to read my SD card at all. Next month, I hope to try machine with software included so that I can get more info.

Make sure you're using the right software for the right machine.

Sleepster

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.
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#18
RE: BiPAP Pressure in the morning
apdtap,

You machine is listed as "Philips & ResMed" in the sidebar beside your posts.

Can you tell us exactly which machine (Brand, make and MODEL number) that you are currently using and having problems with. And exactly which version of SleepyHead you are using and what platform you are using it on.

Quote:If the machine is "clever" enough, it should still reduce the pressure to "none". My respirologist thinks this is irrelevant as I should take off my mask and swicth off the machine anyway.
The machine has NO way to determine whether you are awake or asleep since it has not EEG data and no inertia/movement detectors in it.

The old defunct Zeos used (crude) EEG data to determine the sleep stage. The new Fitbit bands and UP Fit bands use an inertia/movement detector to tell how much you are moving around and they use that data to infer whether you are asleep or awake. But all your BiPAP has is the back pressure data gathered at the blower end of the system: It can track your breathing, but it cannot infer your wake status from the breathing patterns because sleep disordered breathing patterns and normal wake breathing patterns look a lot like each other. The machine's engineers have made the programming decision that the machine will NOT try to guess whether you are awake or asleep when you are using the machine. They've chosen to make the assumption that when you are using the machine, you are most likely asleep. And hence any kind of breathing pattern that is NOT normal, non-sleep disordered sleep breathing is assumed to be a sleep disordered breathing pattern. And if there's enough sleep disordered breathing going on, an APAP will increase the pressure and a BiPAP Auto will increase either the IPAP or the EPAP or both.
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