Hello! More questions from a new user. I am wondering about the extended bolus feature.
My trainer said you can do either a dual wave or a square wave, but as far as I can tell - it's only square. Is that right? I know how the two are different conceptually (dual wave w/ two "mini" boluses at set times and square wave for extended bolus over a set time), but I don't see a way to differentiate between the two wave types in the PDM. Is there one?
Thank you for any help!
Esjay
As far as I know, it’s only extended.
I’ve used it many many times over 5 years…and its only extenned as far as I can tell.
it’s called extended, but you can do it either way…
use the “extend” feature
for SQUARE - set the initial bolus percent to 0%, then select the time you want it to run square
for DUAL - set the initial bolus percent to whatever you want it to give you right then, say 60%, then select the time you want the rest of it to run for.
make sense?
Hi Esjay,
Chandra is right.
I wrote part of the software that does that for the OmniPod. 
Cheers,
Gil
I think my confusion was with the term “dual wave,” which you have cleared up. I thought it implied one “wave” (“wave” really meaning dose) of insulin upfront (let’s say 50%) and another “wave” of insulin in exactly 2 hours (or whatever you set), both “waves” not extended. Almost a two-part bolus, if you will, that had no extended portion. But really, it appears to be a “wave” of an upfront bolus with an additional increased temp basal (for lack of a better description) over a set time. Is that right? Thanks so much!
it is confusing! you are almost right…
SQUARE - it’s distributing a set amount of insulin (bolus) EVENLY over a set amount of time
for example: i set 10 units to deliver over an hour … it will start when i start it and then calculate it evenly over the hour… this might be something i use if i get some popcorn at a movie (not that much insulin for popcorn!!) and know i’ll be eating it throughout, not all at once.
DUAL WAVE - it’s distributing a set amount of insulin (bolus) with a portion delivering INSTANTLY (1st wave!) and the rest continuing to deliver EVENLY over the rest of the set time (2nd wave)
for example: i set 10 units. i tell it to deliver 60% now, so it will give me 6 units like a regular bolus. then i tell it to give me the rest over 3 hours. so it will give me the other 4 units spread out over 3 hours, like the square one above… this is something i would use if i’m eating a high-fat meal like pizza. i definitely want it to give me insulin now when i’m eating, but i know that it will take longer to digest, so i don’t want all the insulin up front.
does that make more sense? : )
Every morning when I eat my plain oatmeal and peanut butter, my CDE has be do 50% now and 50% over 1/2 hour.
There is a slight difference in the way the insulin is delivered when your bolus includes a correction. All the correction insulin is delivered immediately, even if you choose to extend all of your bolus. This is documented on page 36 of my PDM 2 User Guide. When I use extend, this feature almost always kicks in because I usually have a correction component in addition to a meal component.
You can set your PDM 2 to specify the initial bolus in units, percentages or turn off the extend feature as follows:
>Settings
>>System Setup
>>>Bolus/basal/calcs
>>>>Extended:
Then choose %, units or off.
Mine is set to %. I cannot remember if that is how the PDM shipped, or if I changed it during initial training with my CDE.
Thanks everybody for your input. I was clueless about the square wave/dual wave terminology.
That’s right. It’s a good analogy. For example, if you choose 2 hours, the second “wave” is not delivered “at” the 2-hour mark. It is delivered “distributed over” the next 2 hours. As if it were, as your analogy, an additional increased temp basal.
The term “wave” is a little confusing because an engineer invented it, when looking at the insulin delivery graph. On a graph, an immediate bolus looks like a single square wave. While an extended bolus with an immediate portion looks like two (dual) square waves. Think of a “wave” = “portion of a dose”.
Clear as mud?
Cheers,
Gil