Allie said:
I understand that the insulin has a peak and then it tapers off which is the delta. What I don't understand is the mechanism the delta being so big. I believe that a dose increase will cause a bigger delta (he got a .5U dose increase yesterday). But I don't know the underlying 'why' for when this happens.
Just wanted to clarify that delta is simply the difference between the high & the low #s (in any context). You may have meant that.
There are lots of subtle factors as to why they get the drop they get, but the bottom line (for the delta and also for the duration to some extent) is simply dose size. More insulin = greater delta and longer duration. (Discounting for the moment any complicating factors that will change that basic formula.) It sounds like you may be interested in the actual mechanics of how the insulin works, which I can't really help you with, but it seems logical to me (so maybe I'm not understanding your question?). More insulin in their system means the insulin will attack the sugar in their blood (or however it actually works) and that will lead to lower BGs compared to less insulin in their system.
With PZI my understanding is that you want a delta of around 60% give or take 5-10%. More than that tends to be too much of a drop, less than that tends to be ineffective. In my experience it is more useful to evaluate your PSs and nadirs in terms of the % drop rather than in absolute #s. If you are seeing an 80% drop you would want to consider lowering your dose (unless you are aiming for something like that to get out of high #s), and if you are seeing a drop of say 40%, you would want to consider increasing the dose (unless you already have a nadir on the low side and don't want to risk going lower).
So you can't simply deduct yesterday's delta from today's PS and predict the nadir that way. Often the drop will be bigger from a high PS than the same dose on a lower PS - there's sort of a compression effect where it's easy to get a big drop off a high #, but from a lower PS (for some cats) the curve will often be shallower. Which is a good thing really, but can be confusing for dosing until you start to get a feel for the curve patterns.
The thing with insulin is you won't ever find the kind of 1-1 logic that some of us seek. :? You can do some math with it and sometimes the #s cooperate with that, but a lot of times you can't simply correlate that x dose increase will give you y delta, or that x PS will give you y nadir. There are just a lot of factors, but you do get the hang of it after a while and can estimate fairly well a fair amount of the time.
