[CPAP] Introduction

[Sleeprider]

This image lacks inspiratory flow limitation and presents a normal rounded breath. Expiration time is extended quite long, and respiration is about 11 bpm here. I was hoping to see the y-axis scale changed on mask pressure so we could see the amount of pressure rise, but it is clearly near the 2-cm set in the EPR. Again with your settings, a range of 8 to 20 is more appropriate for mask pressure. I think you were in a sleep position that increased airway obstruction in the period from 6:15 to 7:45. You had no events at that time, but pressure was quite high and breathing flow limited.

Pressure Support is a term used in bilevel therapy, and it applies to the use of EPR. It is the difference between inhale and exhale pressure. So with EPR 2 there is a theoretical 2-cm pressure support potential. Pressure support helps inspiratory volume and can help overcome flow limitation by replacing some of your muscular effort with the work or pressure support by the machine. In the spontaneous bilevels like Autoset and Vauto, the machine follows spontaneous effort, and when it is week or obstructed, the full IPAP is not achieved.

[Knitman]

YOU:

This image lacks inspiratory flow limitation and presents a normal rounded breath. Expiration time is extended quite long, and respiration is about 11 bpm here.  I was hoping to see the y-axis scale changed on mask pressure so we could see the amount of pressure rise, but it is clearly near the 2-cm set in the EPR.  

ME:

I thought you wanted to see a graph where the FL was flat.

I did as you asked with the MP-I set it OR and min. 100 and max 100. It is still showing those settings.




YOU:

Again with your settings, a range of 8 to 20 is more appropriate for mask pressure.  I think you were in a sleep position that increased airway obstruction in the period from 6:15 to 7:45.  You had no events at that time, but pressure was quite high and breathing flow limited.

ME:

Perhaps I had turned on to my back? I usually sleep on my right side. ``i do recall this morning, when I woke the first time as my husband went downstairs to deal with the needs of our senile dog, that I rolled over on to my left. When that became too much, I got up. After 8hr10m. Two hours later, I slept again for a further 2hr10m with AHI 0.00. and a pressure of 16 . something. 16.8 I think.

YOU:

Pressure Support is a term used in bilevel therapy, and it applies to the use of EPR. It is the difference between inhale and exhale pressure.  So with EPR 2 there is a theoretical 2-cm pressure support potential.  Pressure support helps inspiratory volume and can help overcome flow limitation by replacing some of your muscular effort with the work or pressure support by the machine.  In the spontaneous bilevels like Autoset and Vauto, the machine follows spontaneous effort, and when it is week or obstructed, the full IPAP is not achieved.

ME:
I am getting confused. Is my therapy working or not? It seems to me that with such low readings it is.  I appreciate you know an awful lot about this therapy but it is now beginning to over my head. Maybe because I am tired and unwell or maybe because i have not learned as much as you. I am. beginning to feel anxious about this.  I have been told by my own clinicians and the Resmed ones that as long as my readings are under 5, the treatment has been successful for that sleep. Is that not the case?

I have no regrets paying for the ResMed as it is very easy to use and very comfortable and very quiet.

If I have understood you correctly, my present setting of 11-20 ought to changed to 8-20? May I ask why? I have never seen it as low as 8. In fact I only see ity as low as 11 when the machine first starts. 

kindest regards

[Sleeprider]

We got to see a segment that was flow limited and one that was normal. That is what I was looking for, is the range of therapy, not just the problem.

I was not suggesting you change settings on your machine, I was trying to instruct you on how to change the y-axis scale on Oscar. It's nothing important, just lets us see things in a higher resolution.

I am trying to teach you the meaning of some terms I use in my posts. I often use bilevel jargon, and wanted to make clear the connection between EPR and pressure support. I will try to be less technical as it seems to throw you off.

Your therapy is doing fine. Do not change your pressure settings, I was referring to the mask pressure chart axis.

[Knitman]

I have returned to my normal sleeping position-sort of laying like an astronaut on take of. This time I have sloped the back more so that I am not bolt upright. Just two nights so far. I forgot to the card in the first night so only have this reading. but the machine said same thing 2.2 episodes per hour and then 1.9 AHI and 1.9 Central, the first night. It still said 2.2 this morning but can't recall the other figures.

Having had a long chat with a clinician, she thinks I am now doing very well. She thinks the fact I am now getting mostly just centrals, it is likely down to me meds, though the brain damage cannot be ruled out. Either way, I will always need the machine. Perhaps all the OA have gone because I have lost 140+ lbs?

   


Despite what it says about the humidifier, I don't have one.

[Knitman]

The bed on left, the adjustable is like the one we have except ours is Cedar wood but the mattresses are Tempure. The one that is not flat is how I sleep but with back and feet set to maximum height, then back set back to make more of a slope.

Commercial Link Removed.  Search Tempur Beds/Mattresses in the UK

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[Sleeprider]

Congrats on the weight loss. I suspect you would still have an impressive AHI without any therapy. Pressures are stable and you are effectively free of obstructive apnea. It's really up to your clinicians if they want to ever move to a therapy that can treat centrals. At this point, I suspect they don't see a need for that.

[Knitman]

Thank you Sleeprider.

How would treatment for Centrals differ?

The post that I made a mistake with was just to show how I sleep. I forgot it was an ad. If you are interested just search adjustable beds. Set at it's maximum feet and back height, but with back now sloping more, is how I sleep.

kind regards

[Sleeprider]

During a central or clear-airway event, the airway is open, there is simply no effort to breathe. The treatment is to use a bilevel with a backup rate that detects the respiration rate has fallen below the target breaths per minute. The machine will increase inspiratory pressure to cause a breath even in the absence of spontaneous effort. The best in class is ASV, but we have seen other technologies used if other respiratory conditions are present. It's very rare for doctors or therapists to recommend a ventilator or respiratory assist device, unless it is clearly medically necessary, which is a hard case to make at your currently good efficacy.

[Knitman]

I have been told that ASV is not possible for me because of my CHF.

[Sleeprider]

It depends. The risk cohort was defined as individuals with CHF and a left ventricular ejection fraction (LVEF%) of less than 45%, and that was a finding that led to abandonment of the SERVE-HF study. The problem was that study has serious design faults, used an older generation of ASV devices, used therapy settings no longer in common use, and used a cohort that was not titrated for efficacy or verified to have used the machines. https://pubmed.ncbi.nlm.nih.gov/26836904/

The mean AHI in the ASV group was 6.6 events per hour which tells you something about how poorly the machines were setup and monitored. The SERVE-HF trial results were widely interpreted as strong evidence that adaptive servo-ventilation was contraindicated for the treatment of central sleep apnea/Hunter-Cheyne-Stokes breathing in patients with heart failure and reduced ejection fraction. While the primary outcome of the trial was negative, the main reported finding of this was driven by analysis that was not part of the statistical original design of the trial and that could not be explained by any mechanistic analysis from the trial data.

Another study ADVENT-HF has been in progress since 2010 with the specific purpose of documenting any risk of ASV to the cohort of CHF patients with LVEF <45%. https://onlinelibrary.wiley.com/doi/full...2/ejhf.790 To date, that study has NOT identified an increased risk from ASV in this cohort, and has identified numerous benefits of treating the central apnea and Cheyne-Stokes Respiration. The study design is considerably different, and uses contemporary ASV devices and a carefully monitored study. https://www.advent-hf.com/

So, the risk is hardly as well defined or a black and white issue, as your doctors are presenting to you, and many CHF patients do benefit from the therapy when central apnea or cheyen-stokes respiration is present. Clearly, some of these individuals suffer greatly when the central AHI is very high. Furthermore, I have queried you about your LVEF in several posts through this thread, and while you did not offer a quantitative response, your description of your current condition and stage of disease, leads me to conclude it is unlikely that you actually match the profile of the "at-risk" cohort with LVEF <45%. The "advisory" against ASV does not extend to CHF in general, but to a specific group of systolic heart failure patients.