My 5 yr old has been on the pod since Dec 2010 and I always assumed that when the basal rate was delivered it was given all at once at the top of the hour ie… 0.10 unit at 12am. Is this true or is the basal rate slowly infused over the hour? I have this question because I have read comments throughout different discussions from people stating that they would never use a “traditional pump” w/ tubing because of d/c for showers etc, their blood sugars go up in 5-10 min which makes me now assume that the basal rate is delivered slowly over the hour. Also, IF the pod does give the basal all at once ie at 12am and you decrease the basal by 50% at 12:30am does it give the 0.05 unit at that time (so your child is actually getting 0.15 units that hour)? My husband said he looked through the instruction book sent with the pump and he could not find that information. Thanks for any info you have
The OmniPod system delivers basal insulin in increments of .05 units evenly throughout an hour. Further, it is delivered conservatively. For example, if the basal rate is .10 and the Pod was activated at the top of the hour, the first .05 pulse would be delivered on the 29th minute and the second on the 59th minute of the hour. If the rate were .20 per hour then pulses would be delivered on the 14th, 29th, 44th and 59th minute.
If you change the rate, the Pod will adjust the intervals based on the number of pulses needed in that hour. So if it’s increased to .15 like in your example, one pulse would be delivered in the first half hour at about the 20 minute mark and 2 pulses would be delivered in the 2nd half hour at about the 40 and 60 mark.
It’s easy to lose the benefit of a temporary basal when setting it only for an hour when using such small increments particularly if you are not programming it coincident with the hour the Pod is calculating its pulse intervals.
Excellent description Lorraine!
Thanks for the information! Makes things much more clear now
Thank you kind sir.
I’m so glad. Please always feel welcome to contact me any time with any questions you have. Caleb has been pumping with OP for almost 4 years. And of course keep posting your questions to benefit from the combined wealth of knowledge that is here.
Wow! I agree. Great explanation, Lorraine! Thank you
It is great to have you on this site. Great explanation.
Yes the pumps deliver basal over the course of the hour, not all at once. It might vary by manufacturer, but i believe Animas delivers basal every 4 minutes. Not sure about time frame on POD, but think they are all similar.
Wow - that is information I always wondered about, but forgot I was wondering about. That’s also incredibly helpful if I can actually remember it in practice . . .
Pumps don’t have a fixed basal delivery interval. They all vary with your basal rate and how much one pulse delivers. So for Animas, it would deliver at every 4 minutes only if, for example, the basal rate is 0.75 U/hr and the pump’s pulse precision / resolution is 0.05 U / pulse. In other words, only if the basal rate is 15 times the pump’s per-pulse resolution, therefore requiring 15 pulses during that hour (every 4 minutes).
I’m not sure if I’m being clear, I’m better with formulas than with words.
Here’s what I’m trying to say:
Interval = 60 / (Rate / Resolution)
We cant increase basal rate temporarily more than 95% with our PDM for omnipod DASH. I would assume that when basal-rate is increased from 0.05 E/h to ~0.09 E/h that it rounds it up to 0.1 E/h and delivers that instead of rounding down to 0.05 ? Else it would make no sense to temporary increase basal rate if the rate is 0.05 since omnipod DASH cant deliver less than 0.05 at a given time.
Anyone knows for sure? Hard to tell from logs from Glooko.
I found my answer.
Basal insulin are given in pulses of 0.05. So this happens when an hourly dose is increased to 0.09:
1st hour: 1 puls given 59th minute of 0.05. Excess insulin of 0.04 is transfered to next hour since pod can’t deliver less than 0.05
2nd hour: total of basal insulin to be given: 0.09+0.04=1.13
Given in two pulses of 0.05 the 29th minute and 59th minute.
and so on. Pod always rounds DOWN, so keep that in mind when increasing basal for 1 hour. for this case increasing for 2-5 hours is the solution to give more.