Oh, thank you! I had bookmarked that article a couple of months ago but never discovered Table 2 in it. I had intended to go back to it later, but then I forgot that I had bookmarked it.
I bookmarked another article about the pressure response algorithm that was done in flowchart form, but now I can't find it.
I was reading the bit about Response to OA/Hypopnea events by the Respironics System One RemStar Auto machine in Table 2
, and I don't understand all of it.
I almost never say this, but I think this stuff would be easier to understand in equation form.
"If 2 apneas or 1 apnea/1 hypopnea or 2 hypopneas-increases by 1 and holds for 30 s
Okay, that first bit makes sense. Two events happen then pressure is increased by 1 cm.
I don't understand the timing of events after that. Does it mean that another pressure increase can happen after 30s if two more events have occurred at that point? And on and on with a pressure increase as often as each 30s until the limit described in the next statement is reached?
*NRAH logic limits max pressure to 11 or 3 higher than preapnea baseline.
*NRAH = nonresponsive apnea/hypopnea logic
??? Does that mean:
If starting pressure = 4-8, pressure can increase up to 11 cm.
If starting pressure = 8.5-17, pressure can increase by up to 3 cm.
If starting pressure is >17, pressure can increase up to max of 20.
Does that sound correct?
If more apneas within 8 min decrease pressure by 2/15 min down to 1 over level that prevents snore then holds pressure for 10 min.
Does that mean "if NO more apneas within 8 min"? I don't understand why the algorithm would want to decrease the pressure if more apneas were happening.
Anyway, if more apneas/no more apneas occur within 8 minutes (8 minutes after the last pressure increase?) then decrease the pressure gradually by 2 cm over a 15 minute period until a pressure is reached that = (Psnore + 1) with Psnore being calculated by another bit of code. Hold that pressure for 10 minutes.
Pressure will continue to increase in response to 2 hypopneas."
Only hypopneas? What happend to two apneas or 1 apnea/1 hypopnea?
I'm very confused.
(06-08-2016, 11:24 AM)rkl122 Wrote:
(06-08-2016, 09:57 AM)green wings Wrote: ...........I am interested in learning more about how the machines work, ................Check out the following link. I first saw it in a post from Robysue, and am grateful for it. Table 2 summarizes the different event algorithms by manufacturer.
Auto CPAP machine algorithms, etc.