02-01-2022, 05:58 PM
RE: Sometimes Waking Short of Breath while on BiPAP - EPAP, PS Settings?
(02-01-2022, 01:32 PM)Geer1 Wrote: Trigger from very high to low is a big change. Higher trigger sometimes helps with centrals so my guess is that low is too low hence the increase in centrals. The centrals are a warning that you have manipulated the settings out of a comfortable range.
Low trigger and high cycle are both trying to force a short inhale but the reality is your spontaneous breathing will drive respiration and fight the machine (with centrals and all sorts of stuff) if you use settings that put the pressure out of sync with spontaneous breathing. You want to use the timing controls to try and match spontaneous breathing not force your spontaneous breathing to change. Trying to force breathing is never the goal unless you have a neuromuscular or hypoventilation issue which I assume you don't.
When working on these timing control settings two graphs are important, flow rate and mask pressure. For trigger sensitivity what you want to see is that pressure increases are being initiated when you take main inhalation and not prematurely during the end of your exhalation. If trigger is too high you will start seeing pressure increase before exhalation has finished and it will often start appearing as two pressure waves per breath (one falsely triggered early and then a second one triggered at inhale). My recommendation is to check if your old very high trigger was causing this and if so slowly adjust it down until that stops happening (in other words try high then normal, don't jump straight to low).
Cycle doesn't seem to clearly cause issues in the same way although many people find it uncomfortable on higher settings because it stops early trying to force you to stop inhaling. I believe it is mostly a comfort setting but if you are seeing pressure drop and flow rate continuing on it is an indicator your cycle sensitivity is too high. Most prefer normal or low rather than the high you are trying to use to force you to exhale.
Similarly you shouldn't need Timin or Timax unless you have medical issues that require it. 0.3 Timin and 2 Timax are fine and shouldn't ever really come into play (most inhalations are 1-1.5 seconds).
I appreciate your feedback as it's helping me learn more about my xPAP therapy.
Last night I left Cycle at HIGH but lifted the Trigger from LOW to Medium and this seems to have had a positive effect. If it carries on this way I might drop Cycle to medium as well but I'll give it a few days. I'll post some charts then and if you don't mind having a look and providing feedback (especially in regards to where the pressure is changing and how that syncs to my spontaneous breathing) it would be appreciated. SevereApnea has already helped me to add to my knowledge base and your post has done the same thing which I am very grateful for.
