I'm not sure what you're trying to say, sounds like you have an apparent misunderstanding of the meaning of the term sanity breath.
The very idea of sanity breaths is that you get off the loop to restore mental acuity, or confirm that your mental acuity is compromised, and that's a physiological falsehood, as pointed out by
@TONY CHANEY . Example, "I got down to depth and felt a little funny so I flipped my BOV to get a couple sanity breaths." That's context in which people use the term. Now if you think it's something else, I'm sorry, but you're just not correct.
You're not talking about sanity breaths it seems, what you're talking about is called bailing out. It's not semantics. To try and play it off like that is disingenuous. Now that doesn't mean you can't sort a problem and get back on the loop, but that is not a "sanity breath." I seriously don't know how you can confuse the two unless you're being intentionally obtuse..
It's most definitely semantics, and one of us does indeed misunderstand the common use of the term, but it's not me.
You've chosen to very narrowly defined "sanity breath" as only applying to getting off the loop to restore mental acuity due or confirm a loss of mental acuity due to hypercapnia - and then defend your position that "sanity breaths" are a falsehood - based on your own very narrow definition of the term. That's very convenient, but the logic is faulty.
The term "sanity breaths", whether you personally approve or not, is commonly used to refer to a CCR diver switching to open circuit for a few breathes while they work the problem and determine what action can be taken or should be taken to get back on the loop.
You are apparently very comfortable calling that "bailing out", despite the lack of distinction between
temporarily getting off the loop to ensure you're breathing a safe gas while you work a problem with the intention of getting back on the loop if the problem can be resolved, and
permanently staying off the loop because a problem, such as a scrubber break through, a complete flood, or just an inability to establish the loop is in fact safe to dive, can't be corrected on the dive.
If you want to disagree with that, that's fine, but please
cite your source saying the term is limited solely to instances when the diver suspects the effects of hypercapnia.
I'm not a major fan of the IANTD manual and have three other more comprehensive manuals that I used prior to or in training, but it defines a "sanity breath as:
"A sanity breath is the act of going to an OC gas or back up rebreather system with an acceptable PO2 and END plus adequate capacity for the depth to be breathed at. The sanity breaths allow the diver to take one or more breaths as needed to evaluate any unusual feelings or symptoms that may be experiencing as well as any suspected problems with the rebreather."
It goes on to describe the applicability to failures that might result in hypoxia, hyperopia or hypercapnia and makes the general point that going off the loop for one or more sanity breaths is often the best reflex action before diagnosing and resolving any problems with the loop.
Whether I like the IANTD manual or not, at a minimum as an aviator trained in the effects of hypoxia, I'll extend the need for a "sanity breath" to the potential effects of low PO2 in the loop (perhaps due to failed electronics). Rather than risk checking out in the time it takes to flush the loop, I'll bail to OC, then flush the loop, confirm the sensor readings and then decide whether or not to go back on the loop.
As Pete indicates, for what I suspect are the majority of us, a "sanity breath" simply means getting on a safe gas source while we determine and if possible resolve a problem with the loop, whether we ultimately go back on the loop or not.
