The biggest issue with the sliding scale method of dosing is that often the doses are "correction doses". That is, the amount of insulin is given because a cat's sugar is outside of a normal range. The problem with this is about half the day, the cat is hyperglycemic...
...The current thought is that we want to be dosing "base doses" instead of "corrective doses". A base does is insulin that is given AHEAD of a blood sugar rise. That is, you give the insulin when the sugar is in the normal range in anticipation of the rise that will occur throughout the day in response to food, activity, stress, and the previous dose wearing off.
Ummm.....
I'm not sure where to start here, and am feeling slightly awkward. And if I said everything I feel should be said this post would get very long indeed, and I don't have time for that, so, I'm going to try to comment on just a few points...
Most cats who are on insulin
will have blood glucose levels outside of a "normal range" (ie,
will be hypergylcemic). It is only a
very lucky few who can consistently keep their blood glucose
in a normal range. And some diabetic cats rarely even come
close to a normal range despite their caregiver's best efforts.
Some cats do very well on fixed doses of insulin. Some cats do well on sliding scale dosage. My cat is in the latter group.
My cat has been on sliding scale almost since he was first diagnosed (8 years ago). It is a system that has worked well for him. Sliding scale means we can adjust the dose according to how the blood glucose level is moving. To me, this actually makes more sense than giving a cat a fixed dose of insulin at every shot. Sliding scale dosage has enabled us to have far greater control of blood glucose levels than we ever had previously on fixed dosing.
The idea of a "base dose of insulin that is given AHEAD of a blood sugar rise" is a sound idea; but in practice it can be extremely hard to
predict in advance what dose will be needed. There are a lot of variables. And it is difficult to calculate with any degree of accuracy "the rise that will occur throughout the day in response to food, activity, stress, and the previous dose wearing off".
With experience gained through data collection it does become
easier to predict what
may happen with any insulin shot (fixed dose or sliding scale), but life can still be unpredictable...
.