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[CPAP] Strange flow patter and results
#1
I am helping  a friends mother, her machine is reporting very high AHI and the AHI reported by the machine is higher than the one sleepy head reports. I suspect there may be a power supply problem? Any one seen any funny bars like these before and what could be causing them She wears a nose mask with a chin strap.

[Image: Dor1.jpg][Image: Dor2.jpg]
#2
My signature has a tutorial on how to organize the Sleepyhead charts so we have the needed information. We want to see Events, Flow Rate, Pressure, Leaks, Snores and whatever else fits.
Use the triangle in the date line to turn off the monthly calendar.
Turn off the right sidebar in the menu View
Turn off the pie chart in File/Preferences/Appearance/ and unclick the pie chart on the right side.

First impressions is that your friend has Complex apnea, which occurs in 10-15% of patients started on CPAP. With a pressure of only 8 cm, the events are evenly distributed between obstructive and central apnea, with a surprising low incidence of hypopnea. I actually suspect the machine is improperly classifying many of the OA events at the end of the night because the respiration rate is so low, and the flow line has the appearance of CA. The BND means breathing not detected, so we need to see the leak graph to see if that is the machine, her breathing or something else. There appear to be numerous leaks, and I would suggest she needs a full face mask. Tis can also cause misleading information to be recorded regarding events.

You should ask your friend if she has a copy of the sleep study, and specifically what fraction of events were CA. Also find out if she had a titration study where she was tested while using CPAP. The ideal treatment for complex apnea is a rather expensive adaptive servo ventilator bilevel machine, the best being the Resmed Aircurve 10 ASV (you can look it up). The leaks cause a LOT of uncertainty here, and many of these events may disappear with a proper fitting full mask. This situation needs to be reported back to the doctor for reassessment for a new mask or ASV. Your friend's mother is fortunate you saw this. The problem does not normally resolve on its own, and can cause very low oxygen levels. She should advise her doctor ASAP, and these charts, or ones re-done as suggested above may be helpful for the doctor to understand what his going on. Hopefully he is qualified to deal with complex apnea.
#3
Prima facie, it appears to be mixed apnea.  The proper treatment is usually the ASV machine.
I suggest following SleepRider's suggestions -- his knowledge is first rate.

The BND is worrisome.  Checking the leaks graph is important.  Since it's a P-R machine, it will report the sum of vent rate and unintended leak.  Sleepyhead will calculate unintended leak; so the leak graph will show two lines.

I would add:  Check to see if auto start/stop (or whatever P-R calls it) is set.  I would disable it so that the machine does not turn off during large leaks or low flow.

@Bruce456:  Your friend's mom should have a cardiac evaluation.  There may be things going on here that are out-of-scope for a CPAP forum.  Plus, before an ASV machine is tried, there is a subset of people in congestive heart failure for which the ASV is contraindicated.
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#4
Thanks for the replies. She is 98 and very touchy about the machine. Her doctor says some treatment is  better than none. Sorry the graphs contain very little info, my friend has a laptop with poor screen resolution so not much appears in the screen shot. On Monday the 27 sleepy head shows an AHI  of 4.34 but the machine says it is 59. I have checked her mask and it looks well fitted with no leaks on a visual inspection with the machine going. Where the grey bars are there is no info on the respiratory rate on the corresponding part of the graph. Still wonder is there is a power problem. Her clock radio would lose the time when i was on the same power board, so I replace the power board and put the cpap machine directly on the power on the wall rather than the power board but it did not make any difference.
[Image: Dor3.jpg][Image: CpapStatsDor.jpg]
#5
If the patient was breathing with her mouth wide open would that cause the BND's ? Breathing not detected. But that would surely show up as leaks? Thanks.
#6
Bruce, there is no problem with the computer these graphs are generated on. it would be a huge help if you would minimize the calendar by clicking the triangle in the date line. That will reveal important summary data below the event smary bars.
Turn off the right sidebar using F10 or the View menu.
Resize the events, flow and pressure so leaks can show up. Since pressure is constant, I'd rather see leaks.

What is her mask? If she has nasal pillows and her mouth is wide open it will result in BND and high leak rates. This is why we need you to make the changes requested above.


#7
it will be a few days before I see her again, but will get more info. The mask is a nasal mask, with a silicon seal around the nose, a forehead strap and another strap lower. But not nasal pillows.
#8
I'm not an expert, but wonder if there may be an intermittent problem with the SD card/card slot in the CPAP machine. The periods displayed as BND (Breathing not Detected) could correspond to times when detailed data was not written to the card. This would explain why SleepyHead is reporting a much lower AHI than the CPAP as SleepyHead isn't seeing and counting the events that occur during these periods while the CPAP is. Maybe worth trying a different SD card (you can copy the existing data if you want) - but I'd also get her supplier/DME to check out the machine.
Your friend is lucky to have you looking out for her. Her Doctor may be correct that some treatment is better than none, but maybe not if the machine providing the treatment is malfunctioning! She deserves to have a properly working machine and for the data from it to be analysed by a medical professional who is in full knowledge of her medical condition/history. If the machine reported AHI of 59 is correct then this is well outside the normally regarded 'treated' zone, however there may be medical reasons why this AHI level can be expected in this case and more effective settings for this condition may not be in the patients overall interest.
Best wishes to you and your friend.
#9
Ok, so I have got some better screen shots. See if anyone can work out why she is getting the grey bars. Breathing not detected. BND's

[Image: Dor4.jpg][Image: Dor5.jpg]


#10
Thanks for fixing the graphs.  The vital information I wanted to see include the respiratory statistics and settings.  In your next submital of graphs, I would really like to get closeups of her breathing flow rates.  A couple images contrasting central events like these graphs show at 01:10 in the first graph, and 03:50 would be helpful.  I'm looking for a graph that shows the individual waveform over a period of not more than 1.5-minutes.  

Your friend is an older geriatric female, and there isn't much documentation or personal experience regarding what is normal or even acceptable.  We can see that the tidal volume and minute vent is far below any normal female.  We would like to see a respiration rate greater than 12 breaths per minute (BPM) but for a small female with low minute vent, a higher rate would be desirable in the range of 14-18.  The reason breathing is not detected is that there is simply not enough airflow for the machine to detect the patient.  There are abundant CA events, and it could easily be true that nearly all the events are obstructive. There is no indication whatsoever of obstructive apnea in the form of snores or flow limitation or even hypopnea.

I'm going to give an opinion and recommendation but want you to know I am not a professional and think this person should be evaluated in a clinical setting using CPAP and PSG to determine a more appropriate therapy approach.  I think her machine selection is poor.  This person should be on a bilevel /BiPAP machine to encourage better ventilation.  Her pressure is too high and she is unable to overcome the fixed CPAP pressure of 8, and I recommend evaluating the results at 6 cm.  I can't emphasize enough that the medical community should not be applying the same principles of treatment for simple obstructive sleep apnea and treatment of normal adult patients to this 98 year old female.  She needs a different approach, and a machine that provides enough pressure relief and pressure support to encourage normal volume and rate of respiration.  An Adaptive Servo Ventilator (ASV) would not be out of the question from what we're seeing here, but again would clearly require professional input.  An older patient like this cannot be treated by a sleep apnea mill, and the problem should be evaluated by someone with awareness of geriatric sleep disordered breathing. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4818236/  https://www.ncbi.nlm.nih.gov/pubmed/11211951


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