Doing my own sleep study - surprising results

[StillAnotherGuest]

As I understand it, a lot of these AutoCPAP/software combinations do not necessarily measure all respiratory events, particularly those caused by flow limitations.

It also seems like even mild forms of sleep-disordered breathing, like UARS, which may be based principally on the flow limitation concept, puts people at risk for cardiovascular problems.

Dr. Sullivan published an article where he talked about OSA and blood pressure

OSA and BP

Where most significantly, he notes:

Unexpectedly, nCPAP at a pressure of 3 or 4 cm H2O reduced mean AHI by 50%, improved sleep structure, and reduced desaturation. NCPAP at the pressure applied is therefore not a placebo but a suboptimal form of treatment, because even the low treatment pressure used here may be sufficient to at least partly reverse upper airway obstruction in many patients. However, the reduction in AHI in the control group would have acted against our hypothesis that nCPAP lowers blood pressure. Despite the reduction in AHI in the subtherapeutic treatment group by 50%, there was no reduction in blood pressure in this group. The unexpected result that suboptimal nCPAP has a substantial effect on AHI but no effect on blood pressure emphasizes the importance of optimal treatment to reduce cardiovascular sequelae.

What this says to me is that even if you "feel better" using APAP, or if your software is saying your AHI is great, it's still not a slam-dunk that you are improving your overall cardiovascular risks.
SAG

[Jerry69]

Ric's right about it being easier to "self-titrate" using an autopap and software. I did it with a 420E and Silverlining software myself, two years ago. No insurance, no doctor, no sleep study. And with LOTS of help from the message boards.

For over three months, though, at the very beginning I was using a borrowed Healthdyne Tranquillity straight cpap. Had to use a tiny screwdriver to adjust the pressure at the back of the machine. I had no manometer, so was just "turning and guessing" when the air flow seemed ok for me.

To this day, I have no idea what pressure I was using during those three months. I felt sooo much more rested each morning, however -- I knew that was a treatment I would continue forever. Also knew I wanted a machine that could automatically find the right pressure as needed. And...I wanted software to show me what the machine was doing. I already knew how I was doing!

Of course, it's better to have a sleep study. I had one two years later. Confirmed that the pressure I was using was correct. Interestingly, it revealed that my sleep was occasionally disturbed by PLMs (periodic limb movements.) A sleep study can tell us more about "sleep" than just what the AHI is.

RG, that is very bold, i.e., doing your own study without even knowing the pressure! And, then evaluating the effectiveness subjectively.

I don't think I could do that. I can't predict what my Smartcard is going to tell me based on the way I feel in the morning. The previous day's activity level, the amount of alcohol consumed, the food eaten, and the state of my digestive system influences my sleep more than xPAP...I think. Even my emotional outlook has bearing. (Had some disturbing dreams last night. Are dreams a good sign or a bad sign?)

But, my untreated AHI was 9.5. Most mornings I read less than 1.0, now. And, I've been on PAP less than 2 months. If my untreated AHI had been 40, I would think that I would feel noticeably better with treatment, but, still, I don't know if I could tell the difference between the results produced by 8 cm and 12 cm.

I feel pretty crummy this morning and I stopped writing this post to read my Smartcard. AHI = 0.4! What the Smartcard doesn't reveal is that my FI was 10/hr. (I'll leave it to you to guess what a 'FI' is. Sorry, just had to set the record straight.)



Thanks CPAP. You did all you could. [Lori, I used the x-large Aura nasal seal the first time last night. Worked well. Thanks for the info on the source.]

Jerry

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CPAPopedia Keywords Contained In This Post (Click For Definition): 420E, manometer, CPAP, AHI, Aura, seal

[Guest]

Dr. Sullivan published an article where he talked about OSA and blood pressure

OSA and BP

Where most significantly, he notes:

Unexpectedly, nCPAP at a pressure of 3 or 4 cm H2O reduced mean AHI by 50%, improved sleep structure, and reduced desaturation. NCPAP at the pressure applied is therefore not a placebo but a suboptimal form of treatment, because even the low treatment pressure used here may be sufficient to at least partly reverse upper airway obstruction in many patients. However, the reduction in AHI in the control group would have acted against our hypothesis that nCPAP lowers blood pressure. Despite the reduction in AHI in the subtherapeutic treatment group by 50%, there was no reduction in blood pressure in this group. The unexpected result that suboptimal nCPAP has a substantial effect on AHI but no effect on blood pressure emphasizes the importance of optimal treatment to reduce cardiovascular sequelae.

What this says to me is that even if you "feel better" using APAP, or if your software is saying your AHI is great, it's still not a slam-dunk that you are improving your overall cardiovascular risks.
SAG

What this says to me is that at a pressure which is too low (3-4cms) the AHI was reduced 50% but there was no effect on blood pressure. Had there not been a cap on the pressure in that experiment, and had the pressure been allowed to to rise to meet the patient's needs as determined by the algorithms of the auto machine, the results would have been different.

If someone using APAP decided all they cared about was a 50% reduction in AHI (as opposed to getting it under 5) and did not utilize the software to identify the optimum range to treat events, they would be under-treated as in the above experiment.

[Sleepless on LI]

Jerry,

So the XL pillows worked out well? No soreness or feeling like it pinched the nares? And how much larger are the XL pillows compared to the large? Do you see just a larger opening in where the air comes through or is the pillow oval shape itself considerably larger? Would you say it was worth it to order them? Yes, lots of questions, sorry.

[Jerry69]

Jerry,

So the XL pillows worked out well? No soreness or feeling like it pinched the nares? And how much larger are the XL pillows compared to the large? Do you see just a larger opening in where the air comes through or is the pillow oval shape itself considerably larger? Would you say it was worth it to order them? Yes, lots of questions, sorry.

Lori, the Aura X-Large nasal seal (that's what Aeiomed calls it) has a larger sealing ridge, but the air supply holes are the same size as the 'Large.' I compared the X-Large to the Swift Large pillows and the sealing ridges are practically the same size. The air supply holes on the Swift are larger, however. So, I'd say that if you like the seal that the Swift provides with Large pillows, you will like the seal of the X-Large Aura pillows.

The new, X-large nasal seal was comfotable, like the Swift, and caused no soreness, nor does the Swift. The Breeze Large pillows do cause soreness for me, but I think this has more to do with the 'nose hook' effect of the head gear. I've ordered X-Large pillows for the Breeze, as well. I'll let you know if they improve the comfort. (The adjustment of the Breeze head gear is crucial to comfort, as has been discussed many time on this forum.)

Jerry

[StillAnotherGuest]

Dr. Sullivan published an article where he talked about OSA and blood pressure

OSA and BP

Where most significantly, he notes:

Unexpectedly, nCPAP at a pressure of 3 or 4 cm H2O reduced mean AHI by 50%, improved sleep structure, and reduced desaturation. NCPAP at the pressure applied is therefore not a placebo but a suboptimal form of treatment, because even the low treatment pressure used here may be sufficient to at least partly reverse upper airway obstruction in many patients. However, the reduction in AHI in the control group would have acted against our hypothesis that nCPAP lowers blood pressure. Despite the reduction in AHI in the subtherapeutic treatment group by 50%, there was no reduction in blood pressure in this group. The unexpected result that suboptimal nCPAP has a substantial effect on AHI but no effect on blood pressure emphasizes the importance of optimal treatment to reduce cardiovascular sequelae.

What this says to me is that even if you "feel better" using APAP, or if your software is saying your AHI is great, it's still not a slam-dunk that you are improving your overall cardiovascular risks.
SAG

What this says to me is that at a pressure which is too low (3-4cms) the AHI was reduced 50% but there was no effect on blood pressure. Had there not been a cap on the pressure in that experiment, and had the pressure been allowed to to rise to meet the patient's needs as determined by the algorithms of the auto machine, the results would have been different.

If someone using APAP decided all they cared about was a 50% reduction in AHI (as opposed to getting it under 5) and did not utilize the software to identify the optimum range to treat events, they would be under-treated as in the above experiment.

But again, that assumes that the machine and software are correctly identifying all of the respiratory events. And in the case of flow limitation, they may not.
SAG

[Guest]

But again, that assumes that the machine and software are correctly identifying all of the respiratory events. And in the case of flow limitation, they may not.

Very good point. They may or they may not. However, the experiment you cited which utilized the intentional application of inadequate pressure, is not a valid argument for that point. Nor is it a valid indicator for the efficacy of XPAP therapy in general or as it specifically pertains to blood pressure. The author concludes the result obtained with suboptimal therapy

emphasizes the importance of optimal treatment to reduce cardiovascular sequelae.

What this says to me is the author feels that the machine and software would correctly identify the respiratory events if used properly (optimally) and would have an effect on the reduction of blood pressure.

[jeepdoctor]

What an incredible wealth of information here. I am awed!!!