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Re: [IP] square wave bolus

At 05:02 PM 12/6/98 EST, Karyn wrote:
>   I was wondering how to figure out the length of time a square wave bolus
>should be set.  I've never used mine for that very reason,  and don't have a
>CDE to contact as I am temporarily out of the US and my current dr. is not
>really up on the pump.  
>   Would the square wave be useful for something like the marathon Christmas
>Eve dinner my Italian in-laws always have?   Thanks in advance and Happy
>Holidays to all!              


I can think of three scenarios in which I would consider using a sqaure wave.

1)  Pizza or mexican food with a lot of fat.  There is no set rule here,
but I've found that bolusing about 1/2 of the amount when I begin to eat,
followed by a square wave of the balance, set for about 1 1/2 to 2 hours
comes out about right.

2)  I've gone hypo right before a meal.  I've treated the hypo with the
correct amount of glucose and want to follow it up with some more
substantial food, but I don't want the insulin for my meal to kick in too
soon, before my bg rises enough.  In this case, I would set a square wave
for about 1/2 hour.

3)  The long, drawn out meal like you describe.  If you sit down to the
meal, and know the amount of carbs you will be consuming, but that you will
be consuming them over a longer length of time than usual, then the square
wave is appropriate.  I think most of us typically take 15 to 20 minutes to
consume a meal.  However, with added conversation, or more courses, a
holiday meal can take quite a bit longer.  In this case, I would extend the
bolus to match the length of time that you will actually be eating.
(unless the food is very high fat, in which case you should extend it
longer, as in the pizza scenario above.)

However, if it is a buffet type meal, with lots of snacking here and there
for an extended period of time, it is difficult to know the amount of carbs
you will actually be consuming.  In these situations, I usually give
several small boluses, as I go, counting the carbs each time I put more
food on my plate.  I had a situation like this last night and am pleased to
say that I came out just fine on the other end with a bg of 117!

To sum up, there really isn't a hard and fast rule to determine the length
of a square wave.  A lot depends on the situation and a lot depends on the
individual.  My time estimates may work for me, but you may need something
different.  Don't feel like you have to get it perfect the first time.  Go
ahead and try something and if it doesn't work quite right, don't be afraid
to make adjustments and try it again.  If you go too high, give yourself a
corrective bolus, if you go too low, get out those glucose tabs.  Then next
time, either extend or shorten the square wave as needed.

Hope this helps, an Italian Christmas Dinner sounds heavenly to me right now!

Mary Jean

Insulin-Pumpers website http://www.insulin-pumpers.org/