High numbers immediately after switching sets

Every time I switch sites I fill canula as usual and I keep getting spikes for a few hours until it settles back down. Does anyone have similar problems. I am an enlite CGM user for about a year and Type 1 diabetic for 24 years.

Yes and so I fill the cannula with a little more insulin to cover it. If you are comfortable with adjusting your own insulin just take it up a little until the issue goes away good luck.

Every time I switch sites I fill cannula as usual and I keep getting spikes for a few hours until it settles back down.

I’m not quite clear on what is happening. Spikes from what? Is this a result of a meal or does you BG just rise as though you have a reduced or non-existent basal?

I have no idea if it is really true, but I think a bolus helps to start a site. I usually try to do my set changes when I also need to bolus at least a unit or more for either a correction and/or carbs. I then wait & watch the CGM to see if my SG (Sensor Glucose) starts to trend down so I can find out if it is “working” or not.

Good advice from the previous replies. I wondered about how long the sites were being used. I tried to stretch the time between changes, but that lead to my blood sugar running high near the end of site’s time. You might try a test with half the insulin in your next change. If you find the same problem with reduced time you can eliminate the age of the site as a factor.

hi @zjohnnyr i think it’s really true: a set change causes local acute trauma at the set site. your body makes histamines and you can get some inflammation as your skin tries to heal. these things interfere with insulin absorption, in some people - it can cause complete occlusion. I totally agree, a bolus helps me get over it, so I actually “fill” my cannula with 2.0 units at set change time (a bolus) to help the high spot created by a set change. it works for me but a person has to be very careful when they are adjusting their own insulin, esp if they are not used to it.

I actually “fill” my cannula with 2.0 units at set change time (a bolus) to help the high spot created by a set change

Using the “fill cannula” function of a pump is not the same thing as a bolus … at least, not to the pump. The pump will not keep track of the insulin pushed for filling either the cannula or tubing using the “prime” functions as part of the “Active Insulin” in your body.

I am careful of that distinction as I do use the “Active Insulin” tracking feature of my pump. I realize others may disregard the distinction, but my feeling is that you do so at potentially your own risk. I think it is better practice to be consistent and use either bolus wizard or the manual bolus function after you have filled the cannula. In my opinion it is better to go high and correct later than to go unpredictably & unexpectedly low.

-iJohn

… but if you need extra, as a result of a high after a set change…then the “active insulin” estimate will be in error, and so it is the precise reason I use the fill as a bolus instead of a bolus. at my next meal the pump won’t subtract for IOB, which is really what I want. plus my set changes are predictable and so (for me) I need the insulin every time. I think we do pretty much the same thing…

anyway the most important thing in my opinion is to figure out what is happening, then figure out what works, and then do it.

cheers!

I have experienced that and played around with a couple of possible solutions.

Initially I increased the Fixed Prime from the recommended 0.5u to 0.6u and this appeared to work. Later I decided to leave in the “old” canula for several hours, after starting a new site, before removing it; this on the assumption that the canula still might contain 0.5 units.

For more than a year I have not used the inflated Fixed Prime rate and the ‘spikes’ have ceased.

Dennis

… but if you need extra, as a result of a high after a set change…then the “active insulin” estimate will be in error, and so it is the precise reason I use the fill as a bolus instead of a bolus.

My personal experience has been that speculating about whether or not the insulin you bolused into your body is actually “there” (i.e. effective) or not is a dangerous way to go.

Speaking quantitatively only in the context of my sensitivity to insulin, I would rather have anything more than a tenth or two of a unit reflected & tracked in my Active Insulin or IOB (Insulin On Board). I would rather run high for a bit and correct it down than learn about the insulin that wasn’t tracked after treating the hypo it resulted in.

What I keep trying to learn over time is that I am not nearly as clever as I often like to think I am.

-iJohn

I used to have a similar problem - it seemed to take quite a bit of time for the insulin to “kick in” via the new infusion set.

I use the Medtronic Quickset 23" infusion sets with the Medtronic Minimed 530g insulin pump.

In my situation, this is how I overcame the problem …

  1. I insert a new infusion set.
  2. I follow Medtronic’s instructions for rewinding, filling tubing, filling the cannula, etc.
  3. I DO NOT REMOVE THE old infusion set (the round sticky part left on my body) until an hour or two have passed. I think that maybe there is some residual insulin that gets through.

Something to think about.

Usually, when I get high numbers after switching my sets, it’s because either I was already high before I changed the site, or my numbers were regular when I switched my set and maybe the basil is now being blocked so your numbers get high. That is how it is for me. I would suggest that immediately after seeing these results, change the site again right away, or how ever many times it takes to lower the blood sugar, in extreme cases, you could use a syringe of insulin if multiple sites do not function.

Usually, when I get high numbers after switching my sets, it’s because either I was already high before I changed the site, or my numbers were regular when I switched my set and maybe the basil is now being blocked so your numbers get high. That is how it is for me. I would suggest that immediately after seeing these results, change the site again right away, or how ever many times it takes to lower the blood sugar, in extreme cases, you could use a syringe of insulin if multiple sites do not function.

I’m new to this group since I never thought of searching (my bad!). I’ve had this same issue since I got on the minimed pumps and now the CGM which I can’t afford due to insurance and sensor cost. I’ve tried everything in this post minus the short tubing (23") idea which doesn’t seem logical if your tubing is primed correctly. Sorry, I don’t mean that in a mean way to the member. The latest thing I have tried and has seemed to work really well for me and the newly inserted infusion set working almost immediately like I never changed it is the set called the Mio.
I think the key here with the Mio is you intentionally have to press it deeper and wait with adhesive pressure which I typically don’t do with say the quickset. Has anyone else noticed this?
The other huge cause in my opinion is the existence of scar tissue.
Cheers to you all. You are all amazing T1D’s!