How to Calculate Percent of Flow Limitation in CPAP Therapy? PLEASE!

Posted by ILoveDoodie @ilovedoodie, Mar 28, 2020

OK, I admit, @johnbishop has both intrigued and freaked me out with the statistics that I am now able to see. Looking at the chart above, I see 1.79 for Flow Limitation. I had to look that term up and found that <30% is cause for concern. Flow limitation for those who don't know: "occurs when increased esophageal pressure is not accompanied by a flow increase. … Its main characteristic is a flattening of the inspiratory flow shape which can be measured noninvasively by nasal prongs at diagnosis or by a pneumotachograph during continuous positive airway pressure (CPAP) titration." This explanation, the least technical one I was able to find 🙄, courtesy of a Google search blurb from Science Direct website which is of the .com variety. I was unable to add a link–the system said no. Articles from other medical websites were very technical and used terms and figures that made my eyes glaze over and my head spin. Judging from the pie chart in the diagram above, assuming it includes my entire night of sleep, my FL was definitely in excess of 30%, but I'm not sure if I am interpreting the chart correctly. Plus, what does the 1.79 number indicate? It's not the percentage. Additional data showed that I had 12 FL events last night, and each had a number in parenthesis next to it 11 (6) and 1 (8). I tried to figure the percentage on my own and I'm lost, totally lost.

I apologize, it may seem as if I am obsessing over unnecessary details, but having researched some new terms and learned that these events can cause memory loss and other bad stuff it makes sense to me that I do what I can to reduce these events. Why are we just told to focus on AHI if it is not the whole story? More details should be provided to Apnea sufferers and in layman's terms for crying out loud. Previously, I had a sleep specialist doc who always said I was just fine, and my PC doc may not be familiar with all this. Nonetheless, I will march in his office on Tuesday (I do have an appt) and present it to him as a challenge.

I honestly do not expect to find a sleep scientist or interpreter of scientific data on Connect who can help, but I am asking. PLEASE HELP IF YOU ARE ABLE!! The creator of this app has, for various reasons, shut down the project therefore there is no help guide to this latest version. @johnbishop which one did you download? Mine looks different than yours. THE END (for now😂)

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@ilovedoodie It's way over my ability (or desire 🙂 ) to figure it out. I downloaded the same one I had on my laptop V1.0.0-beta-2 but I never dug into the deep stat screens like you have.

The role of flow limitation as an important diagnostic tool and clinical finding in mild sleep-disordered breathing


Good morning @ilovedoodie! Hope you had a good sleep last night. It's been awhile since we've posted in the Sleep Health group and I was wondering how it's going for you.

My AHI jumped back up to 5.1 last night but I did get 8.5 hours of fairly good sleep. I still don't understand how to calculate CPAP flow limitation. Mostly because it's difficult for me to comprehend the specific details even though I can read them over and over. Here's one more article I found that explains a lot but not in layman's terms that I can understand.

Physiological consequences of prolonged periods of flow limitation in patients with sleep apnea hypopnea syndrome

Have you found out anymore on the subject of flow limitation?

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