RE: New to APAP. Very, very interesting!
Quote:I am sleeping better than ever!
Great start, and I hope you will stay with the forum to offer your insights as you gain personal experience. Your CA and H is pretty typical for new users, and will settle down shortly to inconsequential levels. Good luck!
RE: New to APAP. Very, very interesting!
(02-16-2016, 03:14 PM)justMongo Wrote: Less EPR will lessen CO2 washout.
I have trouble with that statement. Less EPR would mean more air flow through the mask during exhalation and more CO 2 washout.
Conversely, more EPR would mean less air flow through the mask during exhalation and less CO 2 washout.
Am I wrong?
RE: New to APAP. Very, very interesting!
I think "less EPR" means less of an expiratory pressure relief and thus a greater pressure to exhale against resulting in potentially lower VT and more CO2 retention. "More EPR" means a greater degree of expiratory pressure relief and less resistance to a full exhalation resulting in a potentially higher VT and less CO2 retention. YMMV.
02-16-2016, 07:40 PM
(This post was last modified: 02-16-2016, 07:42 PM by DariaVader.)
RE: New to APAP. Very, very interesting!
(02-16-2016, 07:19 PM)surferdude2 Wrote: (02-16-2016, 03:14 PM)justMongo Wrote: Less EPR will lessen CO2 washout.
I have trouble with that statement. Less EPR would mean more air flow through the mask during exhalation and more CO2 washout.
Conversely, more EPR would mean less air flow through the mask during exhalation and less CO2 washout.
Am I wrong?
EPR is the amount by which the pressure is less. The lower the number, the higher the exhale pressure. So if the pressure is set at 10, EPR of 3 would be 7 on exhale, and an EPR of 1 would be 9 on exhale.
هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه
Tongue Suck Technique for prevention of mouth breathing:
- Place your tongue behind your front teeth on the roof of your mouth
- let your tongue fill the space between the upper molars
- gently suck to form a light vacuum
Practising during the day can help you to keep it at night
هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه هههههه
RE: New to APAP. Very, very interesting!
(02-16-2016, 07:19 PM)surferdude2 Wrote: (02-16-2016, 03:14 PM)justMongo Wrote: Less EPR will lessen CO2 washout.
I have trouble with that statement. Less EPR would mean more air flow through the mask during exhalation and more CO2 washout.
Conversely, more EPR would mean less air flow through the mask during exhalation and less CO2 washout.
Am I wrong?
Yeah, I think you are. More EPR makes it easier to exhale, which is how the CO2 washout occurs in the first place. So if you are having central apneas it makes sense to reduce the EPR so your breath will leave your body more slowly and there will be more time for CO2 to go up in your bloodstream.
The air coming through the blower and through the mask has no CO2 washout, but making your out breaths slower would, or so it seems to me.
I could be wrong.
Ed Seedhouse
VA7SDH
Part cow since February 2018.
Trust your mind less and your brain more.
RE: New to APAP. Very, very interesting!
(02-16-2016, 07:39 PM)Aether087 Wrote: I think "less EPR" means less of an expiratory pressure relief and thus a greater pressure to exhale against resulting in potentially lower VT and more CO2 retention. "More EPR" means a greater degree of expiratory pressure relief and less resistance to a full exhalation resulting in a potentially higher VT and less CO2 retention. YMMV.
When I started almost a month ago I had trouble breathing at a starting pressure of 4 so I change it to 7 but turn on the EPR to 3. This create me some CA. When I putted the EPR at 1 it was much better.
Right now my EPR is off and I'm use to exhale in the pressure without any problems and no more CA
Those change are coming from nice informations in this forum
Good luck in your therapy Aether087!
RE: New to APAP. Very, very interesting!
(02-16-2016, 07:41 PM)eseedhouse Wrote: (02-16-2016, 07:19 PM)surferdude2 Wrote: (02-16-2016, 03:14 PM)justMongo Wrote: Less EPR will lessen CO2 washout.
I have trouble with that statement. Less EPR would mean more air flow through the mask during exhalation and more CO2 washout.
Conversely, more EPR would mean less air flow through the mask during exhalation and less CO2 washout.
Am I wrong?
Surferdude, the easiest way to under stand EPR is to compare it to bilevel pressure support; the difference between IPAP and EPAP pressures. Increased pressure support, results in improved ventilation in any respiratory system. People tend to have higher tidal volume with greater pressure support. This is a good thing for people with respiratory resistance such as COPD, asthma, UARS and other restrictive disease. Even healthy people can benefit from improved ventilation volumes to a certain point. However that greater volume means more gas exchange, and a reduction of CO2 in the blood which can affect respiratory drive. It is a fact that increased pressure support and EPR can increase tidal volume, and thereby cause CO2 washout more than fixed CPAP pressure.
Yeah, I think you are. More EPR makes it easier to exhale, which is how the CO2 washout occurs in the first place. So if you are having central apneas it makes sense to reduce the EPR so your breath will leave your body more slowly and there will be more time for CO2 to go up in your bloodstream.
The air coming through the blower and through the mask has no CO2 washout, but making your out breaths slower would, or so it seems to me.
I could be wrong.
RE: New to APAP. Very, very interesting!
Perhaps we need to define what each of us is calling "washout". My understanding of that term, as it relates to PAP therapy, is that it means the washing out of the CO 2 from the inside of the mask housing.
Different masks have different internal volumes, FF mask having the largest. Nasal pillows have the smallest internal volume. That's why we set the flow generator for whatever type of mask we intend to use. FF masks need additional air flow to wash them out and nasal pillows need a lesser amount.
The salient point would seem to be that the greater the air flow the greater the washout.
Given that, it seems to me that a high level of EPR (decreased exhalation pressure and consequently less air flow through the mask and out the exhaust port) would not wash the mask out as well as a low EPR (no decrease in exhalation pressure and consequently greater air flow through the mask and out the exhaust port).
Am I wrong?
ps, I realize the lungs respond differently to increased exhalation pressure due to how the alveoli work but that's not what we are discussing.
02-16-2016, 09:04 PM
(This post was last modified: 02-16-2016, 09:05 PM by richb.)
RE: New to APAP. Very, very interesting!
(02-16-2016, 03:50 PM)Aether087 Wrote: No CA on my sleep study. AHI was 20.1 with 10% obstructive and 90% hypopnea. Lots of RERAs.
Seem to be following this pattern on the "sleepyhead" reports except for the addition of the central apneas and no RERAs. Physiologically, the CAs are an appropriate response to hypocapnea. I do not think that CAs should adversely effect sleep as this is "normal" and when my PaCO2 rises appropriately, I will take a breath. It does bother me "slightly" when I am falling asleep. I have no problem with continuing my current therapy as it seems to be doing the job. Just wondering if my thinking is correct or if the CAs represent a real problem?
Hi Aether087.
Those Hypopneas could be Periodic Breathing. Periodic Breathing is a precursor to machine induced CAs and could be a result of a malfunctioning response to CO2 levels. The CPAP machine washes out enough CO2 to convert those Hypopneas to CAs. That is why no CAs appeared on your PSG. The fact that you had significant RERAs during your PSG is an indication that a combination of Hypopneas and OA events is interfering with your sleep quality. The first task is to control the OA events. You need enough pressure to keep your airway open but not so much that you convert Hypopneas to CAs. The suggestions from justMongo and DariaVader are a start. Another point is that I do not believe that your current machine records RERAs. That doesn't mean that you don't have them. You may need to download your data frequently since your machine only stores data for about 7 days. Posting graphs from Sleepyhead can get you a lot of suggestions. Your pressure and flow data over 5 to 10 minute periods surrounding "events" will show if your machine is working effectively and could suggest a change in therapy.
RichB
02-16-2016, 09:23 PM
(This post was last modified: 02-16-2016, 09:26 PM by Sleeprider.)
RE: New to APAP. Very, very interesting!
(02-16-2016, 08:18 PM)surferdude2 Wrote: Perhaps we need to define what each of us is calling "washout". My understanding of that term, as it relates to PAP therapy, is that it means the washing out of the CO2 from the inside of the mask housing.
Different masks have different internal volumes, FF mask having the largest. Nasal pillows have the smallest internal volume. That's why we set the flow generator for whatever type of mask we intend to use. FF masks need additional air flow to wash them out and nasal pillows need a lesser amount.
The salient point would seem to be that the greater the air flow the greater the washout.
Given that, it seems to me that a high level of EPR (decreased exhalation pressure and consequently less air flow through the mask and out the exhaust port) would not wash the mask out as well as a low EPR (no decrease in exhalation pressure and consequently greater air flow through the mask and out the exhaust port).
Am I wrong?
ps, I realize the lungs respond differently to increased exhalation pressure due to how the alveoli work but that's not what we are discussing.
I don't want to hijack this thread, but the O.P. has good knowledge of ventilation and probably knows the answer. Respiratory drive is not dependent on the residual CO2 in a mask, but in the blood stream, and that is affected by the minute vent (tidal volume) of respiration. If we relied on CO2 in a mask or the air around us, then people breathing ambient air without CPAP or using a fan at night would be in a world of hurt. In the extreme, consider hyperventilation to extend the period in which you can hold your breath. Air volume through a CPAP mask is over 3 times your respiratory volume and any exhaled air is rapidly vented. It is not the intent of mask designers to retain CO2; quite the opposite.
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