It would be wise for you to have dress rehearsal. The odds are against you getting it perfect , Lantus has a poor record of absorption and can very from day to day by 20%, some days even more.
If it was me I would go with a split dose about 70% of my pump basal...but if I was not going to a water park I would probably go with about 120% of my regular pump basal. When I started pumping my basal dropped about 20%.
Everyone should know what there insulin requirements are when switching back to MDI it should not be a mystery...JMHO
I ran out of sets and had to do this for 48 hours recently. I don't put much stock in formulas, so the way I figured my Levemir was - my total basal on the pump is just under 11 units and my basal before I started the pump (16 months ago) was 16, so I averaged them out and took 13 in split dose. It worked ok, but not perfectly. I really wasn't expecting perfect.
Although insulin numbers are important, insulin is not a perfect science. I agree with JohnG, you should have a test run first. A perfect example of why we should do this is, before I switched to a pump, I was taking about 24 units of Levemir a day. My endo figured my basal in my pump should be set to 1 unit an hour. Well, that was a big mistake, I got really bad lows all the time. Eventually I realized on my own that I only needed .150 of a unit, instead of a whole unit (huge difference). What was my lesson? Insulin formulas are different and will work in each individual's body differently. There is no magic formula that will fit everybody. That's why it's always a good idea to write your I/C and any other important information down.
It would be the same amount as your total basal. My total basal in my my pump is 15.65 units so I would take 16 units of lantus. that has always been the formula.
Also keep in mind that the "Seasons", stress, menstrual period, activity levels, can all effect how much you your dosage will be @ any moment in time. The bad part about basal injections, is that it's one shot that can last up to 24 hours. You can't stop the insulin once you've injected.
During the 48 hours I was back to shots last week, I got 5 hours in range one day and 7 hours in range the next day. I did have a low of 34 and a high of 260. But I believe the low was because I really wasn't used to syringes. (I used pens before my pump) and I was in a hurry to be somewhere the first shot I did and I think I did 2 units instead of 1. The 260 was due to not correcting a 181 at bedtime the night before, as I didn't want to go low. Being limited to one unit steps (and those being pretty inexact with a syringe!) made me really appreciate my pump!
No, based on Humalog does not work.
No, it's not 1:1 after the initial dose when diagnosed. The formula based on weight does not apply after a person has been on insulin and his basal has been adjusted downward.
But, there is a basal amount being given by the pump. Sum it up for each of the 24 hours.
Try out a two dose regimen, figure it for 7 am to 7 or 9 pm; Then figure what was going in from 7 pm to 7 am, or 9 pm to 7 am, whatever is more convenient (I happen to prefer the shorter night routine). Normally the cells need far less over a sleeping period. You can establish it from what the pump dosage is. My percent between day and night is so far off from normal, that I won't even put it down here.
And since this is your first time of summing it, check it out with the endo to see if you're right on.
Note that at the waterpark, exercise will be heightened, so basal should take that into consideration.