Advice for Clear Airway AHI of under 5

[padster]

Hello everyone. As a new CPAP user, I've been reading up a lot in this forum and the time has finally come to participate. First of all, i'd like to thank all the members who have kindly shared their knowledge and experience. The information in here is amazing and has provided really valuable insights to help me learn more about Sleep Apnea & related topics.

I've been feeling sleepy in the daytime for quite some time. Like most people, i thought it was because i was one of those people that need to sleep a lot and that the 6 to 7 hours per night i was getting were just not enough. After hearing about Sleep Apnea from a friend, i decided to have a Sleep Study done. These were the results: 193 events (176 OA, 1 CA, 6 Mixed and 10 Hypopnea) with a 23.4 AHI (21.4 OA, 0.1 CA, 0.7 Mixed, 1.2 Hypopnea). Average Oxygen Saturation at 96.5%.

The ENT surgeon suggested surgery but i opted for CPAP. My DME (who also conducted the home sleep study) set me up with a ResMed S9 and let me test it for a couple of weeks to help me decide on whether it was worth buying. The daily AHI ranges between 3 to 6 which is a huge improvement from 23.4, but i still feel sleepy the next day, even when i sleep for over 9 hours. Initially, i thought it may just take some time for the full 'fresh' effect to come along, but its now over 2 weeks and i've yet to experience that magical feeling which many OSA patients seem to have once they use a CPAP machine. Is this normal? Is 2-3 weeks too short a period to feel the full positive effects? I asked my DME and he initially said that most people would have felt better by now.

When i downloaded Sleepyhead to search for clues in the data, it revealed that the OSA was almost totally gone and that most of the AHI was due to Clear Airway Apnea (averaging 30-40 events per night). For example, on one night when the AHI was 5.03, the OA was 0.42 and Clear Airway was 4.62. On another night when AHI was 3.17, OA was 0.11 and Clear Airway was 3.06.

Concerned that the Clear Airway was an indication of Central Apnea, i read the few top threads about it in here and generally understood that readings from a CPAP machine were not as accurate as a PSG when it comes to diagnosing Centrals, and that Central Apnea patients should use a BiPAP or a OSV.

The time has come for me to make a decision on whether to proceed with the ResMed S9 purchase and i'm wondering whether i have a Central Apnea issue and may need a different machine. It would be great if some of the more experienced members can share their views on some of the things that i'm trying to figure out:

a) Does the 0.1 Central Apnea score from the Sleep Study confirm that i do not have a Central Apnea issue or can these studies be inaccurate
b) Should i get another Sleep Study done to recheck my Central Apnea reading and confirm that the Clear Airway reading from the CPAP is not indicative of Centrals
c) Even if it is Central Apnea events, since it is under 5 AHI most of the time, is it unnecessary to consider BiPAP or ASV

Edited to Add: d) Shall i just go ahead with the ResMed S9 APAP purchase since it is sorting out my OSA issue

Thanks in advance for all your feedback and suggestions.

[Lizistired]

Welcome! A couple of questions...
How long have you been using the machine?
What is your prescribed pressure?
What are your machine settings? Pressure, auto or cpap, ramp. EPR...?
What is your leak rate?

[archangle]

It often takes more than a few weeks to feel better physically.

Sometimes, you're just in the mental rut of not having any energy.

Even if your sleepiness isn't due to apnea, CPAP can still be the difference between life and death or serious health problems.

Look at the detail data and see how long your CA events are, and how completely you stop breathing.

[Bons]

During a sleep study, the tech is observing you and knows when to count a disruption in breathing as a central apnea and when to ignore it. The S9 is not watching you, so it does not know if you are asleep or awake, turning over in your sleep, flipping your pillow, and stuff like that. So it counts every time you pause in breathing as an apnea. There is also what is called "sleep onset" central apneas as our bodies transition from awake breathing to sleep breathing (which is neurologically different) and when we transition between sleep stages.

So, while you MIGHT have central apnea, it is not likely. Can you look at your data from an entire night and see when the "centrals" are occuring? If you lay awake for a long time before falling asleep, or lay half awake in the morning, that can put your AHI up artificially. If you are tossing and turning in your sleep and near-rousing because you are still getting used to your new bed partner, that can up your central ahi as well.

It's below 5, so there is no big cause for alarm. Something to discuss with your doc when you have your follow-up.

[Todzo]

Hello everyone. As a new CPAP user, I've been reading up a lot in this forum and the time has finally come to participate. First of all, i'd like to thank all the members who have kindly shared their knowledge and experience. The information in here is amazing and has provided really valuable insights to help me learn more about Sleep Apnea & related topics.

I've been feeling sleepy in the daytime for quite some time. Like most people, i thought it was because i was one of those people that need to sleep a lot and that the 6 to 7 hours per night i was getting were just not enough. After hearing about Sleep Apnea from a friend, i decided to have a Sleep Study done. These were the results: 193 events (176 OA, 1 CA, 6 Mixed and 10 Hypopnea) with a 23.4 AHI (21.4 OA, 0.1 CA, 0.7 Mixed, 1.2 Hypopnea). Average Oxygen Saturation at 96.5%.

The ENT surgeon suggested surgery but i opted for CPAP. My DME (who also conducted the home sleep study) set me up with a ResMed S9 and let me test it for a couple of weeks to help me decide on whether it was worth buying. The daily AHI ranges between 3 to 6 which is a huge improvement from 23.4, but i still feel sleepy the next day, even when i sleep for over 9 hours. Initially, i thought it may just take some time for the full 'fresh' effect to come along, but its now over 2 weeks and i've yet to experience that magical feeling which many OSA patients seem to have once they use a CPAP machine. Is this normal? Is 2-3 weeks too short a period to feel the full positive effects? I asked my DME and he initially said that most people would have felt better by now.

When i downloaded Sleepyhead to search for clues in the data, it revealed that the OSA was almost totally gone and that most of the AHI was due to Clear Airway Apnea (averaging 30-40 events per night). For example, on one night when the AHI was 5.03, the OA was 0.42 and Clear Airway was 4.62. On another night when AHI was 3.17, OA was 0.11 and Clear Airway was 3.06.

Concerned that the Clear Airway was an indication of Central Apnea, i read the few top threads about it in here and generally understood that readings from a CPAP machine were not as accurate as a PSG when it comes to diagnosing Centrals, and that Central Apnea patients should use a BiPAP or a OSV.

The time has come for me to make a decision on whether to proceed with the ResMed S9 purchase and i'm wondering whether i have a Central Apnea issue and may need a different machine. It would be great if some of the more experienced members can share their views on some of the things that i'm trying to figure out:

a) Does the 0.1 Central Apnea score from the Sleep Study confirm that i do not have a Central Apnea issue or can these studies be inaccurate
b) Should i get another Sleep Study done to recheck my Central Apnea reading and confirm that the Clear Airway reading from the CPAP is not indicative of Centrals
c) Even if it is Central Apnea events, since it is under 5 AHI most of the time, is it unnecessary to consider BiPAP or OSV

Thanks in advance for all your feedback and suggestions.

Hi padster!

Regarding your questions:

a) Does the 0.1 Central Apnea score from the Sleep Study confirm that i do not have a Central Apnea issue or can these studies be inaccurate

Keep in mind that a sleep study is in lab, cumbersome, and a single night in front of strangers to boot. They need to be improved. It indicates that on that night, in that environment, at that particular time you had 0.1 Centrals, nothing more or less.

b) Should i get another Sleep Study done to recheck my Central Apnea reading and confirm that the Clear Airway reading from the CPAP is not indicative of Centrals

I think you have better tools with your data capable PAP and SleepyHead. They are with you, in your own bed, and watch you night to night over time. While the data is rather uncalibrated and somewhat limited - the in the home and over time aspects I believe more than make up for the lacks!

c) Even if it is Central Apnea events, since it is under 5 AHI most of the time, is it unnecessary to consider BiPAP or OSV

You are new to PAP, it does take getting used to. Lets not run ahead of ourselves.

Keep in mind the protocol for inducing a central apnea in a human being. You crank up the PAP level 2 cm/H20 every five minutes until a central occurs! Yup, PAP use can cause centrals, it is called Complex Sleep Apnea by the medical community. I think the issues of breathing stability are little understood even in that community! A sad thing indeed!

What is likely happening is that your breathing reflexes are not used to the constant pressure of the PAP and so allow your breathing to become unstable – to “take off” if you will with you breathing too much to the point where arousals occur which is likely what is causing your sleepiness.

The way the medical community looks at this, it is something that time will likely heal. You develop better reflexes and so more stable breathing. Problem solved – most of the time.

I am in a similar situation due to rapid loss of weight. I moved to a place with hills and change altitude about a hundred feet anywhere I want to go. It is also a mile to the nearest store – and – since I cannot guarantee vigilance I do not drive. Heeding my daughters advice to eat more protein I have dropped ten pounds of weight and probably converted another five to muscle. The instability does not present in AHI at all much of the time, although clear airway apneas, as Respironics calls them, would catch my eye as a possible indicator. I look for this mostly in my Periodic Breathing data looking closely at the incident flow waveform – drag over the incident and SleepyHead will show you that space close up. I also look carefully at the Minute Volume, Tidal Volume, and Respiratory Rates. I start with Minute Volume – last night my AHI was 0.84 but my Minute Volume numbers:

Minute Vent.Minute Ventilation (L/min)
min mid 95% max
W-Avg: 7.42 0.12 7.38 10.88 21.12

For me right now I like to see the mid under 6.00 and the 95% under 8. If the charts do not show any times when things really got out of hand I know I will feel very good with those numbers. But as you can see that is not the case, so I likely have found out why I feel good but not great today. I will likely see my productivity drop off a bit early today as well. AHI is one end of the spectrum and breathing stability is the other. The goal is to have both under control.

In my pursuit of breathing stability I am:

Doing aerobic and interval training using these hills and walking a lot.
Have joined a health club to do some resistance training and possibly Yoga.
Have purchased a little $50.00 pulse oximeter I keep with me on a belt pouch at all times. I use it to do what I call optimal breathing training. Simply, you vary your breathing to produce the lowest heart rate while holding exertion constant. The oximeter portion is very useful in this. First of all it takes considerable concentration to reduce your blood oxygen (SpO2) level a single point. Second, once you find the lowest heart rate in a given situation if you note the SpO2 level you will be well on your way to finding the lowest rate in a similar situation in the future. When I first started I would find the lowest rates while working at my desk around 95% SpO2 and exercising moderately on my treadmill at 97%. Now these rates are found about a percent lower for each situation. While doing this I have found that a stuffy nose means I am breathing too much. It was so nice to smell the flowers this spring! Cold hands or feet are a clue, as is a lack of attentiveness for me. When you slow the breathing down you can feel your feet much better as you walk I find.

The weight loss has me using the pulse oximeter again at night to slow my breathing as I first use the CPAP while falling asleep. Breathing less is usually good while on CPAP as it tends to move you toward breathing more. With less weight I have a tendency to have less AHI but breathing is more unstable.

Currently the loss of weight has me pursuing a pressure reduction on my CPAP. Until then and beyond then I will be doing what I have mentioned above as I believe better breathing reflexes make PAP therapy go better and better PAP therapy means I get more done and happier while I do it.

May we find the most restorative sleep!

Todzo

[padster]

Welcome! A couple of questions...
How long have you been using the machine?
What is your prescribed pressure?
What are your machine settings? Pressure, auto or cpap, ramp. EPR...?
What is your leak rate?

@Lizistired

How long have you been using the machine? ... It's the 3rd week at the moment
What is your prescribed pressure? ... I'm not too sure as the doc did not tell me directly. Should he? He just liased with the DME who set me up after i told the doc i prefer PAP to surgery.
What are your machine settings? Pressure, auto or cpap, ramp. EPR...? Mode: APAP 4-20cmH2O
What is your leak rate? For the first week, i tried the Nasal Pillow where Leaks were about 12 (95%) to 24 (Max). With the Full Face Mask in the last 1-2 weeks , its 0 (95%) and 2-3 (Max).

Please let me know if there's any other data from SleepyHead that may be useful in providing you with a clearer picture of what's going on.

Look at the detail data and see how long your CA events are, and how completely you stop breathing.

@archangle - Thanks for your feedback. Where can i find that data in SleepyHead? From what i can see, when i click on the purple Clear Airway bar, it lists the Clear Airway events in the format #001: 02:44:01 (10) .... i resume the number in brackets may be the number of seconds. It ranges between 10-15 with highs at about 21.

The other area where i can see some time based figure is in the 'Duration' reading above the Flow Rate graph. Most of these are at 00:00:51 or 00:00:53 so i'm not sure if they're accurate or the stats that you requested.

Can you look at your data from an entire night and see when the "centrals" are occuring?

@ Bons - Thanks for your feedback. From what i can see, about 15% of them are at the start, 25% are in the morning within an hour of waking up and 60% of the events are scattered throughout the night.

it is something that time will likely heal

@ Todzo - Thanks for sharing your experience. I'm also in a similar situation of doing more exercise and observing how it affects different parts of my health. What type of oximeter do you use ... would you recommend it?

[archangle]

Look at the detail data and see how long your CA events are, and how completely you stop breathing.

@archangle - Thanks for your feedback. Where can i find that data in SleepyHead? From what i can see, when i click on the purple Clear Airway bar, it lists the Clear Airway events in the format #001: 02:44:01 (10) .... i resume the number in brackets may be the number of seconds. It ranges between 10-15 with highs at about 21.

Look at the airflow waveforms. Eyeball when you stop breathing and read the time off the graph. Look at how completely you stop breathing. The machine may count time when you are still breathing, just breathing less than normal.

[Lizistired]

I gather you never had a titration. They just set your machine wide open.

[Pugsy]

Try not to lay in bed with the mask and machine on for prolonged periods of time...see if some of those centrals go away.
How is your sleep? How many hours of sleep? Is it fragmented for any reason...meaning are you awakening during the night at all and if you are...what are you doing and roughly how long are you awake and is it possible that some of the centrals scored during the night could be happening while you are awake?

Do you take any meds at all, even OTC? If so what are they, dosage and when you take them?

[archangle]

Try not to lay in bed with the mask and machine on for prolonged periods of time.

Do you mean to not lie there if you're awake and can't sleep?

[Pugsy]

Pugsy wrote:Try not to lay in bed with the mask and machine on for prolonged periods of time.



Do you mean to not lie there if you're awake and can't sleep?

Yes, thank you. I have a headache and not thinking clearly.

TO OP....what I am trying to do is see if some of that Central index is from awake events which we can't count. So if you have a tendency to lay in bed and toss and turn and think about getting up long before you get up...stop doing that for just a little while to see if those centrals occurring near wake up time will disappear.

[padster]

Look at the detail data and see how long your CA events are, and how completely you stop breathing.

@archangle - Thanks for your feedback. Where can i find that data in SleepyHead? From what i can see, when i click on the purple Clear Airway bar, it lists the Clear Airway events in the format #001: 02:44:01 (10) .... i resume the number in brackets may be the number of seconds. It ranges between 10-15 with highs at about 21.

Look at the airflow waveforms. Eyeball when you stop breathing and read the time off the graph. Look at how completely you stop breathing. The machine may count time when you are still breathing, just breathing less than normal.

There's only a 'flow rate' graph in my Sleepyhead, i presume that's the same as airflow. Not sure how to 'eyeball' ... i highlight over an area where there's an event and the graph/waveform zooms in. When its at a maximum zoom level, i click on the purple line indicating a Clear Airway and the Duration indicator shows 00:01:13 ... i figure something can't be right if that means i stopped breathing for over a minute. When i do the same for any of the other 40 Clear Airway events on the same night, the durations are all the same at 1:13 which just seems odd.

Please can you advise on what i should look at to see "how completely i stop breathing" or even "breathing less than normal"?

I gather you never had a titration. They just set your machine wide open.

No, i didn't. I'm not exactly sure of what's supposed to be done by who. The ENT surgeon i saw wasn't very informative and did not communicate much, other than to suggest surgery. Once i opted for PAP, he referred me to the DME who seemed to know and share a lot more info. So, i'm not sure who was supposed to do the titration, and whether the levels are decided by the doc and set on the machine by the DME, or whether the DME coordinates it all. I presumed that since it's an APAP, there's no need for specific titration and the machine automatically adjusts to the optimum level to suit the patient's needs. Thanks for any feedback.

Try not to lay in bed with the mask and machine on for prolonged periods of time...see if some of those centrals go away.
How is your sleep? How many hours of sleep? Is it fragmented for any reason...meaning are you awakening during the night at all and if you are...what are you doing and roughly how long are you awake and is it possible that some of the centrals scored during the night could be happening while you are awake?

Do you take any meds at all, even OTC? If so what are they, dosage and when you take them?

Appreciate your suggestions Pugsy...

- Try not to lay in bed with the mask and machine on for prolonged periods of time ... I don't really lay in bed awake for any length of time with the mask on. At night, i fall off to sleep pretty quickly and in the morning, i take it off as soon as i'm awake, and am just so glad to get it off. Sometimes, i do get up to see what time it is and then go back to sleep if i don't need to get up for another hour or so, but i don't lie in bed (with the mask on) pondering about whether i should get up or not.

- How is your sleep? ... My sleep is generally quite good without any real fragmentations. Used to get up in the middle of the night to go to the bathroom regularly before using PAP but rarely ever do it now.

- How many hours of sleep? ... Getting minimum 7 hours, normally 7-8+ and 9+ hours on some days.

- Do you take any meds at all ... Not at all.

[Bons]

"Bons wrote:
Can you look at your data from an entire night and see when the "centrals" are occuring?
@ Bons - Thanks for your feedback. From what i can see, about 15% of them are at the start, 25% are in the morning within an hour of waking up and 60% of the events are scattered throughout the night."

Which can pretty much indicate that you don't have problematic central sleep apnea. If we can discount almost half of them as sleep onset/transitional centrals, that cuts your AHI from centrals down to about 2.4 for the night? That doesn't seem like a major issue.

I have complex sleep apnea. When I started on cpap, it took care of all my obstructive apneas. But my AHI went up rather than down, because I then had pressure induced centrals adding to the centrals that I already had. That's why I have the ASV.

[Lizistired]

Padster, Can you post a screenshot of your sleepyhead data,
Drag the graphs around so you can get the Event flags, pressure, flow rate, leak, flow limitation, and minute ventilation in one shot.
You can probably titrate yourself, but we need to see what's going on.
Here are Pugsy's image posting instructions.

We have to host them on a website and link to them.
I use screen shots and Photobucket because I found it super easy but other use different methods.

This is my standard "how to post images of reports" speech.

Open the image to full size so it is easily read.
I use Vista snipping tool to create a screen shot and crop the image at the same time.
Prt/scr key will also take a screen shot if using XP. If laptop is used sometimes the Fn key has to be pushed at the same time as the prt/scr key
I think windows 7 Home Premium has the snipping tool, Basic may not.

Once the screen shot is created save it in jpg format.
Upload the image to a host site. I use Photobucket it is free, there are others.
Once the image is uploaded then copy the ENTIRE IMG address. Be sure to include the opening and closing IMG in brackets. Paste that copied address into a post here.
Use the preview button. If you can't see the image try again because if you can't see it we can't.

[Todzo]

it is something that time will likely heal

@ Todzo - Thanks for sharing your experience. I'm also in a similar situation of doing more exercise and observing how it affects different parts of my health. What type of oximeter do you use ... would you recommend it?

It is a Model: Concord Sapphire by Concord Health Supply. I got it from Amazon. It does seem to do the job well. It is a bit overly sensitive (reads SpO2 high) with new batteries for the first hour and needs to be cleaned once in a while but the included belt pouch is a plus - there all the time for Optimal Breathing Training or Interval training without needing to dawn a chest strap (I love that!).

Have a great week!

Todzo