Thanks, Den, for looking that up...about snores being reported with ResScan. I'm glad to know that, now.
carbonman wrote:
I live at 12.5-17cm.
If I understand it correctly, this machine would do nothing for me.
Please correct me it this is not the case.
If you mean you have your Respironics machine set for minimum pressure 12.5 and maximum pressure 17, then setting a ResMed machine for that same range would quite likely treat you just as well as your Respironics machine does, imho.
The A10 algorithm used by ResMed autopaps is misunderstood too often, imho, as meaning that if a person was prescribed more than 10 cm from a sleep study, OR has set their minimum pressure for more than 10 cm, then a ResMed autopap is out of the running completely. I don't think that's so.
ALL autopaps, including ResMed, respond with more pressure to
flow limitations. That cannot be stressed often enough, imho. ALL autopaps respond by raising the pressure when they sense "flow limitation" (partial -- not full -- collapse of the airway.) Most people's breathing does show signs of flow becoming limited (as
-SWS pointed out) well before the airway would collapse on into full closure.
To try to correct the flow limited breathing, autopaps will keep raising the pressure all the way up to the maximum in the range, if need be. Just like any other brand of autopap, a ResMed autopap would raise the pressure all the way to your max of 17, carbonman, if needed....to try to open the airway if it senses your breathing is becoming "flow limited" due to partial collapse of the airway. Snores are often first sign indicators of a partial collapse starting, so autopaps respond to snores, too.
Responding with more pressure when flow limitations or snores are sensed
PREVENTS most apneas from occurring at all.
That's how a ResMed autopap (and any other brand of autopap) treats people,
even if the person has set more pressure than 10 cm as their minimum pressure, or has been prescribed more pressure than 10 from their sleep study. The ResMed autopap treats them by doing what
every other autopap does, too -- by responding with more pressure (even more than 10) when the least little sign of
flow limited breathing is sensed.
With any brand of autopap it's really all about
preventation in the first place. Dealing with and eliminating
flow limitations is the way
all of them go about trying to
prevent an
apnea from happening, as I understand it.
So -- what happens if a sudden apnea sneaks through despite any brand of autopap's best efforts at preventing that from happening?
ResMed chooses to wait it out. Waits for that odd, random apnea to clear on its own (by the person's brain arousing him/her enough to breathe again.)
Respironics chooses to try three
small pressure nudges, to see if the airflow will improve with a SLIGHT bit more pressure. We're not talking full cm jumps with those nudges. We're talking fractions of a cm at a time, and giving it time between each nudge to see what happens. If no improvement is seen after the final nudge, Respironics is not going to try to "treat" that apnea further. It, too, will wait it out at that point, and will even drop the pressure back down to before the nudges started.
There really isn't much difference, imho, between "waiting it out" and "waiting it out after some mild pressure nudges to see what happens." I think it's not very often that a few tentative small pressure nudges will make much difference to an apnea that is already well and truly in place. Either way, that sudden apnea is probably going to just have to run its course, with
either of those two major brands of machines. After the person has had an arousal that gets them breathing again,
then the autopaps will continue trying to prevent more apneas from happening, by doing what they do best -- continuing to watch for flow limitations and treating those partial closures with more pressure.
I think this next thing is important to keep in mind, if a person has the opportunity to try both brands of autopap and starts looking at the data from each to try to see which one "treats" them better:
If you used both brands of autopap, you would probably see a higher AHI reported by a ResMed machine than from a Respironics machine. But that higher AHI will almost certainly have
nothing to do with "ResMed will not increase pressure for an apnea above 10 cm." Nor would it mean that one brand was noticing something the other was missing, or that one was imagining something the other knew was not there. Nor would it mean that one brand was treating you better than the other.
The higher AHI that's likely to be seen from a ResMed machine has to do with the way different manufacturers draw a line in the sand to define when a "flow limitation" is to be called "hypopnea." Your
AI (apnea index) is very likely to be reported as the same, or similar, low number from either brand of machine. But the
HI (hypopnea index) is very likely to be higher from a ResMed machine, simply because of the different definitions for "hypopnea" that the two manufacturers use. I mentally cut the Hypopna index in half when I use a ResMed machine, if I want to compare my AHI results to the AHI I get from a Respironics machine.
Again, a bottom line: Regardless of the difference in the AHI report (mainly due to the difference in the "HI" part of the AHI) from those two brands of machines for the same person, the effectiveness of the treatment the person has had from either machine when they wake up in the morning, is very likely going to make the person feel the same. Most people (not "all..."most) are likely to feel just as good (or bad) using one machine as the other.
There can be different features built into different manufacturers' autopaps that can make people prefer one over another, or even do better on one over another. I personally find Respironics' A-Flex and C-Flex exhalation features to be more comfortable and "natural breathing feeling" than I do ResMed's EPR. So, when I want to use "autopap" I use my Respironics Auto with A-flex.
I also find Respironics' Bi-Flex feature in their bilevel machine (BiPAP) more comfortable than I do with any of the rise time and Inspiration max/Expiration min "comfort" features in ResMed's bilevel machine (VPAP.) So, when I want to use a "bilevel", I use my Respironics BiPAP Auto with Bi-Flex.
However, anytime I use a ResMed cpap, autopap, or bilevel machine, I've gotten exactly the same "well rested" feeling in the morning that I get from any Respironics machine. I get the same good treatment from any of them. I chalk the higher AHI" from ResMed up to the difference in "HI" definitions...I cut the ResMed HI in half...and I then see the same data results from either brand.
There are people, of course, who will do better on one type (cpap, autopap, bilevel) of machine, or one particular brand of machine, than on others. I'm lucky that any type or brand can treat me equally well.