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+--- Thread: Flow Rate wave form has sharp peaks (/Thread-Flow-Rate-wave-form-has-sharp-peaks)
Flow Rate wave form has sharp peaks - dloomis - 01-06-2025
Hi everyone - new PAP user here. I notice that for large parts of my evening my wave form has sharp peak with a steep drop off at exhalation instead of the rounded tops that I've been told is the goal of therapy. What does this wave form show, and if it's abnormal what can I do to remedy it? This is from last night and I feel very rested.
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RE: Flow Rate wave form has sharp peaks - Sleeprider - 01-06-2025
This is actually a class II flow limitation that your machine is missing for some reason. Your inspiration flow rises sharply from zero then diminishes through the rest of the breath before declining to zero-flow (red line), and becoming expiration. We can quickly solve this by increasing minimum pressure from 6.0 to 7.0, leaving maximum pressure at 11.0 and adding EPR Full-Time at Setting 2 or 3. Is this flattened or declining inspiration flow typical throughout the night? See the Flow Limitation wiki https://www.apneaboard.com/wiki/index.php?title=Flow_limitation
RE: Flow Rate wave form has sharp peaks - dloomis - 01-06-2025
Thanks for the quick reply.
Will setting EPR=2 at 7 cmH2O provide enough expiratory pressure support to prevent mouth leak? I've been struggling with that as a new user and from what I've been reading having high expiratory pressure will help give the soft palate proper support. Thanks again for your insight.
And yes, there are periods where I have perfect rounded wave forms. But these tend to dominate.
RE: Flow Rate wave form has sharp peaks - Sleeprider - 01-06-2025
Although expiratory pressure will be a bit lower with EPR, it should help, rather than hurt any mouth leaks. With EPR on, pressure will rise during inspiration to provide support where your airway becomes more obstructed with higher inspiratory flow and effort. It should work well for you.
We can work on mouth leaks as a separate issue. If you sleep on your side, try pulling a corner of your pillow between your shoulder and jaw to physically help keep your jaw closed. You can practice speaking while under pressure, and sipping water through a straw. This teaches airway control. It may take a few tries to get it, but eventually the skill in preventing leaks while talking or sipping water can translate to the subconscious sleep state.
RE: Flow Rate wave form has sharp peaks - dloomis - 01-06-2025
Thank you! I'll change to APAP 7-11 with EPR=2 tonight and will report back with hopefully positive results.
RE: Flow Rate wave form has sharp peaks - dloomis - 01-07-2025
(01-06-2025, 10:24 AM)Sleeprider Wrote: Although expiratory pressure will be a bit lower with EPR, it should help, rather than hurt any mouth leaks. With EPR on, pressure will rise during inspiration to provide support where your airway becomes more obstructed with higher inspiratory flow and effort. It should work well for you.
Reporting back after setting EPR=2 with APAP 7-11 per your recommendation. Wave forms look much better! Does this mean I'm a good candidate for bi-level? Or is bi-level only for those on higher pressures? I thought EPR was only a comfort setting; I didn't realize it could help in this way.
P.S. I'm stilling getting consistent flattened peak that the Resmed algorithm either responds to or doesn't. I'm assuming this means I need to titrate higher until this is eliminated.
RE: Flow Rate wave form has sharp peaks - Sleeprider - 01-07-2025
EPR works in the same way as PS in a bilevel. You have not used the maximum EPR available to you yet. I can show you side-by-side images of the Airsense 10 and Aircurve 10 mask pressures, and the way pressure support is delivered is nearly identical except bilevel allows PS above 3.0 cm. The hardware on your Airsense 11 is identical to the Aircurve 11, and only the firmware is different. I think if we were able to dig deep into the actual logic, that we would find the CPAP is actually a bilevel with limited PS capability. So to answer your question, if you get good results with CPAP, there is no need to spend the money on bilevel. For any continued inspiratory peak flattening, just increase minimum pressure a bit and move to EPR 3.