I'm fairly new to CPAP Therapy. I started out on a Resmed VPAPIII (Bi-PAP) for a month and switched to a Remstar Auto (both with heated humidifiers). I also have Encore Pro and, thanks to Derek, My Encore. That's one of the reasons why I switched. The other reason was the I felt the pressure of 16 cm that I was titrated at was too high all night long and I had a difficult time with CPAP Therapy at that continuous pressure.
The first few days using the APAP indicated the a pressure of about 9 cm solved 90% of my AHI (Sleep study AHI of 51) and a high pressure around 10 cm. That was great news, AHI around 8.1 and not as tired the next day. What could be better than this?! The next few days, however, I required higher pressures to overcome apnea events - mostly OAs and half as many Hypopneas. Looking at the data from Encore Pro I found that my OAs got worse and required much higher pressures (I limited the max to 16 cm based on the sleep doc's recommendation) during the last quarter of my sleep period - last two hours. In fact. I think the pressure whould have gone higher if the maximum was set higher.
My question is, "Can higher pressures during the sleep period lead to greater obstructions/narrowing of the airways thus requiring higher pressure yet to overcome apnea events?" It seems like it can be an upward spiral. For me it felt as though higher pressure tended to cause a narrowing of the airways, causing the need for higher pressures, etc. Has anyone experienced this?
I know, that I only have a week on APAP and not really enough time to come to any valid conclusion and I will monitor my progress over time but with the higher pressure needed the more difficult CPAP therapy seems to be. I also realize there can be many other factors involved such as the heat setting for the humidifier (I use the Aussi heated hose to prevent rain out and it works!), or perhaps what food I had during the day, and sleeping position, etc.
Also, thanks to all of you on this forum for the great assistance and support. I know I'm getting better sleep therapy by becoming more knowledgable of my problems and what sloutions there are available. I do have to chuckle a little when I turned in my rental Bi-Pap to my DME supplier(I guess I should say former DME supplier) because I wanted a machine and software they couldn't supply. I was the only one in their many years of experience who has ever done that. On the negative side I had to pay for the new machine up front and hope my health care insurer will reimburse a portion of it. I guess the DME supplier is chuckling a little too.
Wishing all happy Holidays...
Can higher pressure lead to greater obstruction?
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rested gal
- Posts: 12880
- Joined: Thu Sep 09, 2004 10:14 pm
- Location: Tennessee
Peels, I'm just making a wild guess at this -- my guess would be that you are seeing what happens during your normal longer periods of REM as morning approaches.Looking at the data from Encore Pro I found that my OAs got worse and required much higher pressures (I limited the max to 16 cm based on the sleep doc's recommendation) during the last quarter of my sleep period - last two hours.
REM periods normally last increasingly longer amounts of time the longer we sleep during a night. Our longest REM is usually near morning.
Apneas and hypopneas are most apt to be worse when we are in REM.
Sleep position can make a difference too, in the number of events we have. Supine (lying on one's back) being the worst for OSA for most people.
Possibly you were on your back quite a bit during your last couple of hours sleep, AND were in REM for a fairly long period. Both factors could have been making your throat more collapsible and causing the machine to have to use more pressure to deal with it in the hour or so approaching dawn.
You asked:
Again, just a guess -- I don't think higher pressure per se would do that. However, as you quite rightly brought up, other factors could have an effect.My question is, "Can higher pressures during the sleep period lead to greater obstructions/narrowing of the airways thus requiring higher pressure yet to overcome apnea events?" It seems like it can be an upward spiral. For me it felt as though higher pressure tended to cause a narrowing of the airways, causing the need for higher pressures, etc.
Too much or too little humidification might cause a change in the airway - congestion, swelling.
Perhaps you have allergies or sinus problems that get worse as the night goes on?
Any kind of tissure swelling in the throat or nasal passages could be causing more restricted air flow on some nights. Congestion might simply be getting worse the longer you've been lying down.
Swelling of throat tissue (as opposed to collapse of the throat) is not going to respond to air pressure trying to push the tissue aside. Soft collapsed throat tissue will yield to air pressure trying to move it back. However, swollen tissue is made more rigid by the swelling and can't readily be moved by air pushing against it.
You might remember the interesting problem Loonlvr had. He was not able to get good treatment from two different autopaps until he experimentally added OTC Prilosec (for suspected undiagnosed "silent" GERD) and benadryl (in case tissue swelling was a problem.) Not saying you should do that; just mentioning it as an interesting mystery about "events" and "pressure" that was apparently solved through considering other health factors.
Nov 05, 2005 subject: SUCCESS AT LAST-GERD,420E, PRILOSEC AND BENADRYL
My bet though - sleep position and REM are more a factor for you, Peels. Perhaps a bit higher setting for the low pressure in your range -- raising the low to 10, as you're thinking about doing -- would allow the machine to deal with those later hours events better.
Good luck!
Rested Gal,
Thank you. You might have hit the nail on the head. It is possible that I am having a problem from tissue swelling. Thanks for the link as well. There are some similarities and I have had some swelling of the vocal cords that my ENT Physician believes might be due to allergies. Nasal passages seem to be open.
But then again I am new to my machine and I had the heat on the humidifier up to level 5 and that may have added to some swelling. When the setting was on one I didn't seem to have the swelling in my throat - more like an arid dessert. I think maybe I will experiment a little tonight. Lower the temperature of the humidifier and raise the minimum pressure level a little.
Wow, you gave me lots to think about. Getting CPAP therapy right isn't just finding the correct pressure setting. There's a lot more to it...
Thank you. You might have hit the nail on the head. It is possible that I am having a problem from tissue swelling. Thanks for the link as well. There are some similarities and I have had some swelling of the vocal cords that my ENT Physician believes might be due to allergies. Nasal passages seem to be open.
But then again I am new to my machine and I had the heat on the humidifier up to level 5 and that may have added to some swelling. When the setting was on one I didn't seem to have the swelling in my throat - more like an arid dessert. I think maybe I will experiment a little tonight. Lower the temperature of the humidifier and raise the minimum pressure level a little.
Wow, you gave me lots to think about. Getting CPAP therapy right isn't just finding the correct pressure setting. There's a lot more to it...
Peels:
It would be extremely rare for higher pressure by itself to cause an increase in obstructive events - and such a scenario would require a very abnormal nose/mouth/tongue/throat/geometry or condition.
It is possible - although again extremely rare for higher pressures to cause a central apnea. This should have been identified in the sleep study (do you have a copy of it - or did the Dr mention this?).
As Rested Gal (RG) has indicated- a variety of other factors can affect the needed pressure each night.
One item RG did not mention is that just being short of sleep itself increases the number of events and the need for pressure on subsequent nights. Thus, if you need a normal pressure of 11, but am running at 9. the next night you might need 13, and the night after that 15, and the next night you would hit the max setting of 16.
I am curious though. If your machine is set for a max of 16 - what is your minimum setting. Usually machines need to be set somewhere reasonable in relation to the max pressure needs in order to be able to respond fast enough when events start happening. For example. If your peak need is 16, you might try setting the minimum at 11 and see how it works for a week.
Perry
It would be extremely rare for higher pressure by itself to cause an increase in obstructive events - and such a scenario would require a very abnormal nose/mouth/tongue/throat/geometry or condition.
It is possible - although again extremely rare for higher pressures to cause a central apnea. This should have been identified in the sleep study (do you have a copy of it - or did the Dr mention this?).
As Rested Gal (RG) has indicated- a variety of other factors can affect the needed pressure each night.
One item RG did not mention is that just being short of sleep itself increases the number of events and the need for pressure on subsequent nights. Thus, if you need a normal pressure of 11, but am running at 9. the next night you might need 13, and the night after that 15, and the next night you would hit the max setting of 16.
I am curious though. If your machine is set for a max of 16 - what is your minimum setting. Usually machines need to be set somewhere reasonable in relation to the max pressure needs in order to be able to respond fast enough when events start happening. For example. If your peak need is 16, you might try setting the minimum at 11 and see how it works for a week.
Perry
Perry,
I have the minimum setting at 6 cm and perhaps it is too low. Can too low of a setting on an APAP be a problem? The APAP came with a minimum setting at 4 cm but I felt deprived of air at that setting so I bumped it up a bit.
Is there a rule of thumb that the difference between the max and min setting shouldn't be greater than a certain amount say 4 cm? I probably can afford to bump the pressure up a bit more as the magic 90% pressure level has varied from 9 to 13.
As you can see, I could surely use a book "CPAP Therapy for Dummies" if there was one but thanks to this forum I do not feel as helpless.
Again thanks,
I have the minimum setting at 6 cm and perhaps it is too low. Can too low of a setting on an APAP be a problem? The APAP came with a minimum setting at 4 cm but I felt deprived of air at that setting so I bumped it up a bit.
Is there a rule of thumb that the difference between the max and min setting shouldn't be greater than a certain amount say 4 cm? I probably can afford to bump the pressure up a bit more as the magic 90% pressure level has varied from 9 to 13.
As you can see, I could surely use a book "CPAP Therapy for Dummies" if there was one but thanks to this forum I do not feel as helpless.
Again thanks,
Absolutely. Setting it too low allows a lot more significant events to occur - which disrupts your sleep a lot more. You want the minimum setting to be at a point where the minimum setting takes care of most of the lessor problems and only has to respond when you get into serious trouble. Also, the machines have response times and actually usually ramp up fairly slow - which prevents them from waking you by ramping up to fast (lessons the Mfr's have learned).Peels ask:
Can too low of a setting on an APAP be a problem?
Several years ago I ran a series of test on this issue. In my case - on my primary APAP I must have a range of 4 (16-20). If I set the min at 15 (range of 5) I will within several days move into exhaustion (and I verified that several times). A range of 3 did not improve things. My backup APAP (different Mfr) I was able to use a range of 5 - except that the machine does not fully work for me and I cannot get to full mental zest with it (I will always be somewhat tired). On the other hand - that machine can wake me up with its fast response to certain events as well.
Since your magic range seems to be 9 - 13; why don't you set your machine there (min at 9 and see how you feel after a week (and what the nightly pressure charts are telling you).
I really don't like the minimu setting at 4 that comes from the Mfr. Some mask will not flush enough air at 4 cm H2O.
Perry
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rested gal
- Posts: 12880
- Joined: Thu Sep 09, 2004 10:14 pm
- Location: Tennessee
I agree with Perry that 4 cm H2O is often too low for most people to be comfortable breathing through a mask. Most report feeling they have to work too hard to breathe down at 4. You're not going to suffocate, but it can sure feel like it.
It's also unnecessarily low for optimum operation of an autopap for most people. Especially for people who perhaps came away from the sleep study with a pressure they need only rarely during a night, or who have to deal with a high pressure in general. However, many posters have reported getting "smoother" sleep and feeling better when they put the low pressure of their autopaps right up on or just a cm or two below their titrated pressure.
I used to think the only reason really to have an autopap was to enjoy good treatment with pressures much lower than a titrated pressure most of the night. For some, that is the case. But for many of us, the autopap serves another purpose....letting us use titrated or just below titrated pressure most of the night, yet having a margin above that available for use when needed.
When might "more" than titrated be needed? There are lots of scenarios. Perhaps a change of meds, unusually stressful day, partying a little too much, illness, more congestion than usual, allergies acting up...the list can go on and on. And of course, there's always the chance the sleep study titration missed the mark in the first place.
I've experimented with a lot of different ranges with all three major manufacturers' autopaps, and had the software to download from each. For me (and it can be very different for others) a range starting with 8 or 9 as the low works best. I can set the upper pressure anywhere at all as the machines rarely ever need to use more than 14 for me, and then only briefly on random nights. Most of the time, my autopaps stay down on 9 or 10 all night.
Why did I decide to put my lower pressure up on 9? It was because experimentally I could test it while wide awake. Lying in bed, with machine going, while I was waiting to drift off to sleep, I could feel my throat close if I had set my autopap's low pressure at anything less than 8 or 9. I could very distinctly feel it shut off all air if I deliberately and consciously let my throat relax as much as possible. I knew if I could "make" that happen while I was awake, it was definitely happening in the more complete relaxation of sleep. So, there was no point in my setting the machine below the threshold that would keep my relaxed throat open to start with.
Hey, what can I say? I guess I'm a straight cpap'er at heart.
But I'll always use an autopap -- for the extra pressure it can provide when occasionally needed.
It's also unnecessarily low for optimum operation of an autopap for most people. Especially for people who perhaps came away from the sleep study with a pressure they need only rarely during a night, or who have to deal with a high pressure in general. However, many posters have reported getting "smoother" sleep and feeling better when they put the low pressure of their autopaps right up on or just a cm or two below their titrated pressure.
I used to think the only reason really to have an autopap was to enjoy good treatment with pressures much lower than a titrated pressure most of the night. For some, that is the case. But for many of us, the autopap serves another purpose....letting us use titrated or just below titrated pressure most of the night, yet having a margin above that available for use when needed.
When might "more" than titrated be needed? There are lots of scenarios. Perhaps a change of meds, unusually stressful day, partying a little too much, illness, more congestion than usual, allergies acting up...the list can go on and on. And of course, there's always the chance the sleep study titration missed the mark in the first place.
I've experimented with a lot of different ranges with all three major manufacturers' autopaps, and had the software to download from each. For me (and it can be very different for others) a range starting with 8 or 9 as the low works best. I can set the upper pressure anywhere at all as the machines rarely ever need to use more than 14 for me, and then only briefly on random nights. Most of the time, my autopaps stay down on 9 or 10 all night.
Why did I decide to put my lower pressure up on 9? It was because experimentally I could test it while wide awake. Lying in bed, with machine going, while I was waiting to drift off to sleep, I could feel my throat close if I had set my autopap's low pressure at anything less than 8 or 9. I could very distinctly feel it shut off all air if I deliberately and consciously let my throat relax as much as possible. I knew if I could "make" that happen while I was awake, it was definitely happening in the more complete relaxation of sleep. So, there was no point in my setting the machine below the threshold that would keep my relaxed throat open to start with.
Hey, what can I say? I guess I'm a straight cpap'er at heart.
But I'll always use an autopap -- for the extra pressure it can provide when occasionally needed.
Could Be?
Hi PEELS:
I see you were initially set up at BiPAP 16/12. Curious as to how they got there, could've just been the higher pressure, or perhaps there were some mixed or centrals. If you get the sleep study results, make sure you grab the Pressure Titration Table.
There is an entity, Complex Sleep Disordered Breathing, where respiratory events get worse with pressure. The titration table, along with the event breakdown on diagnostic, may offer a clue.
deltadave
I see you were initially set up at BiPAP 16/12. Curious as to how they got there, could've just been the higher pressure, or perhaps there were some mixed or centrals. If you get the sleep study results, make sure you grab the Pressure Titration Table.
There is an entity, Complex Sleep Disordered Breathing, where respiratory events get worse with pressure. The titration table, along with the event breakdown on diagnostic, may offer a clue.
deltadave
Perry and RG,
You cleared up a good part of my confusion. My first thought was to have the pressure set as low as possible and like you mention, at 4 cm I don't feel like I'm getting enough air.
Well, I raised the minimum pressure to 7.5 cm last night. I thought about raising it from 6 cm to 9 cm but compromised with myself and split the difference in half, thus 7.5. (sometimes I get lucky and agree with myself). I left my maximum at 16 cm. Result: a much improved night of sleeping. I woke up twice during the night - which is highly unusual for me. Usually, I wake up at least every other hour and often find it difficult to get back to sleep. Last night has been my best night so far while on CPAP therapy. I went from 22 AHI the previous night down to 11 AHI last night. Both are better than the 51 AHI during my sleep study. By the way, my snores were down to 1.1 per hour from 9 per hour. Just by raising the minimum pressure a little sure does wonders on the log cutting.
Ok, tonight I'm going to raise the bar as you suggest and set the minimum at 9.0 and set the max one cm higher from 16 to 17. If my sleep improves even further I may have to reverse my screen name!
I have to say that two two things are working for me: this forum of course and having the download data to review. Both are valuable.
Thanks all
George (Peels)
You cleared up a good part of my confusion. My first thought was to have the pressure set as low as possible and like you mention, at 4 cm I don't feel like I'm getting enough air.
Well, I raised the minimum pressure to 7.5 cm last night. I thought about raising it from 6 cm to 9 cm but compromised with myself and split the difference in half, thus 7.5. (sometimes I get lucky and agree with myself). I left my maximum at 16 cm. Result: a much improved night of sleeping. I woke up twice during the night - which is highly unusual for me. Usually, I wake up at least every other hour and often find it difficult to get back to sleep. Last night has been my best night so far while on CPAP therapy. I went from 22 AHI the previous night down to 11 AHI last night. Both are better than the 51 AHI during my sleep study. By the way, my snores were down to 1.1 per hour from 9 per hour. Just by raising the minimum pressure a little sure does wonders on the log cutting.
Ok, tonight I'm going to raise the bar as you suggest and set the minimum at 9.0 and set the max one cm higher from 16 to 17. If my sleep improves even further I may have to reverse my screen name!
I have to say that two two things are working for me: this forum of course and having the download data to review. Both are valuable.
Thanks all
George (Peels)
Deltadave,
I have a copy of two sleep studies that the Sleep Study physician sent to my ENT physician. I did not notice any mention of central apnea, which perry also asked. Unfortunately, there was no pressure titration table included with the results that I received (I guess I should say, asked for). No doubt, the sleep lab should have the information. Will sleep labs offer to provide this type of information to their patients? They do not usually like to provide information to anyone but the sleep physician especially the detailed data.
You did, however, provide an interesting lead that I will do a little research on.
Thanks,
George
I have a copy of two sleep studies that the Sleep Study physician sent to my ENT physician. I did not notice any mention of central apnea, which perry also asked. Unfortunately, there was no pressure titration table included with the results that I received (I guess I should say, asked for). No doubt, the sleep lab should have the information. Will sleep labs offer to provide this type of information to their patients? They do not usually like to provide information to anyone but the sleep physician especially the detailed data.
You did, however, provide an interesting lead that I will do a little research on.
Thanks,
George
First of all I have to give everyone a BIG THANKS. Your ideas and recommendations are working.
Perry, as you mentioned it does make a difference how far apart I set the min and max pressures. Last night I set my min for 10 cm and max for 14 (a little below the titrated pressure of 16 cm). I've had my best night so far with an AHI of 4.6 events per hour. This is a significant difference from the 18 to 22+ AHIs I had the previous several nights (sleep study AHI of 51 events per hour) when I had the min and max pressures further apart. I can see myself doing more trials here hoping to improve further.
I have to join in with RG that having an APAP is wonderful. It is so much better for me not having to withstand high pressures all night long. And one night's sleep study may not be perfect for determining the right pressure setting. There are many factors that affect breathing every night.
I am still a little concerned about the Complex Sleep Disordered Breathing that deltaDave mentioned as I tend to see more apnea events at a higher pressure level. And as RG indicated, ther may be some throat swelling that is causing more events at higher pressure levels.
By the way, if you don't mind I have a few newbie questions about the data from Encore Pro and My Encore. ( I think that I know the answers but not sure). PS. Thanks Derek for your sharing with us.
First, in Encore Pro an Apnea event is an 80% reduction in airflow for 10 seconds or more compared to an average airflow over several minutes. And a hypopnea is similar but a 40% reduction. This came from the help function in Encore Pro. So, apneas and hypopneas are basically the same except for primarily the level of airflow restriction? (and hypopneas can be for 10 to 60 seconds).
Second, what is the definition of flow limitation? Is this just a less severe hypopnea?
My last question I am almost embarrassed to ask. What is the definition of a Non-responsive Apnea? I am assuming that it is an apnea event that the machine at the pressure it is currently at cannot improve airflow - just guessing. If I had several of these at the max pressure setting, does that mean the max setting should be raised?
Again, thank you for all your help. It has been really meaningful. I'm learning things about what is going on with my breathing (or should I say non-breathing) and sleeping, everyday. I think that I've become addicted to this forum and need to get my fix everyday - and I read every topic!
George
Perry, as you mentioned it does make a difference how far apart I set the min and max pressures. Last night I set my min for 10 cm and max for 14 (a little below the titrated pressure of 16 cm). I've had my best night so far with an AHI of 4.6 events per hour. This is a significant difference from the 18 to 22+ AHIs I had the previous several nights (sleep study AHI of 51 events per hour) when I had the min and max pressures further apart. I can see myself doing more trials here hoping to improve further.
I have to join in with RG that having an APAP is wonderful. It is so much better for me not having to withstand high pressures all night long. And one night's sleep study may not be perfect for determining the right pressure setting. There are many factors that affect breathing every night.
I am still a little concerned about the Complex Sleep Disordered Breathing that deltaDave mentioned as I tend to see more apnea events at a higher pressure level. And as RG indicated, ther may be some throat swelling that is causing more events at higher pressure levels.
By the way, if you don't mind I have a few newbie questions about the data from Encore Pro and My Encore. ( I think that I know the answers but not sure). PS. Thanks Derek for your sharing with us.
First, in Encore Pro an Apnea event is an 80% reduction in airflow for 10 seconds or more compared to an average airflow over several minutes. And a hypopnea is similar but a 40% reduction. This came from the help function in Encore Pro. So, apneas and hypopneas are basically the same except for primarily the level of airflow restriction? (and hypopneas can be for 10 to 60 seconds).
Second, what is the definition of flow limitation? Is this just a less severe hypopnea?
My last question I am almost embarrassed to ask. What is the definition of a Non-responsive Apnea? I am assuming that it is an apnea event that the machine at the pressure it is currently at cannot improve airflow - just guessing. If I had several of these at the max pressure setting, does that mean the max setting should be raised?
Again, thank you for all your help. It has been really meaningful. I'm learning things about what is going on with my breathing (or should I say non-breathing) and sleeping, everyday. I think that I've become addicted to this forum and need to get my fix everyday - and I read every topic!
George
Hi George
Welcom to the Weird Wonderful World of having apnea with cpaptalk support.
The asnwer to your questions is
1) yes
2) yes
3) yes... the apnea didn't resolve withing the time frame Respironics set for it to reslove after it pressure was bumped up three times.
Or, more complex:
What Resprionics defines as a hypopnea is what (hopefully) Respironic's measures as a hypopnea, and I understand the manual the same way you do.
Does everyone define a hypopnea like that? Not necessarily.
Is the definition important? Yes, if someone has a breathing pattern that falls outside Respironics' definition.
For the benefits of those who don't read every topic, here's another dicsussion of the subject recently.
viewtopic.php?p=57261#57261
O.
Welcom to the Weird Wonderful World of having apnea with cpaptalk support.
The asnwer to your questions is
1) yes
2) yes
3) yes... the apnea didn't resolve withing the time frame Respironics set for it to reslove after it pressure was bumped up three times.
Or, more complex:
What Resprionics defines as a hypopnea is what (hopefully) Respironic's measures as a hypopnea, and I understand the manual the same way you do.
Does everyone define a hypopnea like that? Not necessarily.
Is the definition important? Yes, if someone has a breathing pattern that falls outside Respironics' definition.
For the benefits of those who don't read every topic, here's another dicsussion of the subject recently.
viewtopic.php?p=57261#57261
O.
_________________
| Mask: AirFit™ P10 Nasal Pillow CPAP Mask with Headgear |
| Additional Comments: Machine: Resmed AirSense10 for Her with Climateline heated hose ; alternating masks. |
Thanks OZIJ.
That actually clears up the relationship among Non-responsive Apnea, Apnea, Hypopnea, and Flow limitation that I couldn't find spelled out anywhere. In simple terms, these can be thought of as events that are more severe than the other starting with Flow limitation as the least severe. Its all starting to fit together.
Three nights in a row and I'm having a relatively comfortable sleep with an AHI less than 5 (still unbelievable in my mind) and that's only after I found the right minimum and maximum pressures with no more than 3 or 4 cms between the two limits.
Thanks, now things need to stay stable for awhile and tweak my lower pressure limit if necessary.
George
That actually clears up the relationship among Non-responsive Apnea, Apnea, Hypopnea, and Flow limitation that I couldn't find spelled out anywhere. In simple terms, these can be thought of as events that are more severe than the other starting with Flow limitation as the least severe. Its all starting to fit together.
Three nights in a row and I'm having a relatively comfortable sleep with an AHI less than 5 (still unbelievable in my mind) and that's only after I found the right minimum and maximum pressures with no more than 3 or 4 cms between the two limits.
Thanks, now things need to stay stable for awhile and tweak my lower pressure limit if necessary.
George
-
Snoredog
PEELS wrote:
Yes, a flow limitation can be seen as a less severe hypoapnea. There are 3 criteria that defines a hypoapnea;
50% reduction of air flow
Lasting 10 seconds or longer in duration
Causes drop in Oxygen saturation of 3%
Anything less than the above is considered a flow limitation. So if you only had a 40% drop in flow, or it was short lasting only 8 seconds in duration or it didn't cause a 3% drop of oxygen levels, you would classify that event as a flow limitation and not a hypoapnea.
Autopaps can easily determine what your normal flow-rate is during normal breathing. They store that information in memory. They can also easily time things for duration. What most cannot do is determine your oxygen level (exception being the Reslink). Note: That 80% figure given by the EncorePro help is Respironics own definition of what an apnea event is (for their machine to respond a certin way, not as defined by ABSM).
More definitions:
APNEA = cessation of airflow for 10 seconds or greater.
HYPOAPNEA =>50% decrease in airflow for 10 seconds or greater with a decrease in oxygen saturation of >3%.
APNEA/HYPOAPNEA INDEX (AHI) = apnea plus (+) hypoapnea/hour of sleep.
Technically, only ONE of the autopap machines on the market can actually detect a hypoapnea and that is the Spirit when equipped with the Reslink option. Then the A10 algorythm doesn't trigger off hypoapneas, it triggers off of flow-limitation, snores and apnea. The reason is in order to be classified as a hypoapnea it has to show a reduced flow of 50% lasting longer than 10 seconds (the easy part) PLUS a drop to SAO2 levels by at least 3% to be classified as a hypoapnea. None of the autopaps on the market today come equipped with Pulse Oximeters except for the Spirit where it is an recent optional add-on.First, in Encore Pro an Apnea event is an 80% reduction in airflow for 10 seconds or more compared to an average airflow over several minutes. And a hypopnea is similar but a 40% reduction. This came from the help function in Encore Pro. So, apneas and hypopneas are basically the same except for primarily the level of airflow restriction? (and hypopneas can be for 10 to 60 seconds).
Second, what is the definition of flow limitation? Is this just a less severe hypopnea?
My last question I am almost embarrassed to ask. What is the definition of a Non-responsive Apnea? I am assuming that it is an apnea event that the machine at the pressure it is currently at cannot improve airflow - just guessing. If I had several of these at the max pressure setting, does that mean the max setting should be raised?
Yes, a flow limitation can be seen as a less severe hypoapnea. There are 3 criteria that defines a hypoapnea;
50% reduction of air flow
Lasting 10 seconds or longer in duration
Causes drop in Oxygen saturation of 3%
Anything less than the above is considered a flow limitation. So if you only had a 40% drop in flow, or it was short lasting only 8 seconds in duration or it didn't cause a 3% drop of oxygen levels, you would classify that event as a flow limitation and not a hypoapnea.
Autopaps can easily determine what your normal flow-rate is during normal breathing. They store that information in memory. They can also easily time things for duration. What most cannot do is determine your oxygen level (exception being the Reslink). Note: That 80% figure given by the EncorePro help is Respironics own definition of what an apnea event is (for their machine to respond a certin way, not as defined by ABSM).
More definitions:
APNEA = cessation of airflow for 10 seconds or greater.
HYPOAPNEA =>50% decrease in airflow for 10 seconds or greater with a decrease in oxygen saturation of >3%.
APNEA/HYPOAPNEA INDEX (AHI) = apnea plus (+) hypoapnea/hour of sleep.
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Snoredog
PEELs wrote:
Answer to your question is NO do NOT increase pressure. My understanding is they are Central Apnea events (the Remstar can detect those), but I know prior to version 1.37 that feature in the software didn't work so well if at all. I just recently loaded 1.5 and Derek's software but I haven't had a chance to look at it yet. I had a few centrals seen on my PSG's. If you are seeing Non-Responsive apneas recorded then I would be careful setting the pressure to high above your last PSG titration for that reason. Those can be pressure induced central apneas, if you increase pressure you can make them worse.
Sorry, on the Non-Responsive Apnea question, are you getting a lot of those?What is the definition of a Non-responsive Apnea? I am assuming that it is an apnea event that the machine at the pressure it is currently at cannot improve airflow - just guessing. If I had several of these at the max pressure setting, does that mean the max setting should be raised?
Answer to your question is NO do NOT increase pressure. My understanding is they are Central Apnea events (the Remstar can detect those), but I know prior to version 1.37 that feature in the software didn't work so well if at all. I just recently loaded 1.5 and Derek's software but I haven't had a chance to look at it yet. I had a few centrals seen on my PSG's. If you are seeing Non-Responsive apneas recorded then I would be careful setting the pressure to high above your last PSG titration for that reason. Those can be pressure induced central apneas, if you increase pressure you can make them worse.