One issue I’ve been struggling with since moving to a Tandem CIQ pump is Stubborn High Syndrome. I know everyone has that from time to time but it seems to be happening a lot more frequently now. Days when no amount of pre-bolusing/correcting/over-estimating carbs etc seems to affect it. Even resists exercise with IOB. Initially I thought, “Bad insertion site,” but after a number of times swapping out insets prematurely it’s starting to seem like something else is going on. It really seems like the pattern is consistent with just getting down to day 3 of a reservoir, specifically when it gets down to ~30 units or so.
Could be wrong, of course. There are a lot of failure points to consider. Could be me/my body, though I never had this problem with my old (OLD) pump—I frequently went to a fourth day if I wasn’t eating many carbs. So I just want to know if this is a thing for other Tandem users.
I’m using Fiasp, btw, which is “off-label” I know, but lots of others use it including my Tandem-certified pump trainer…
I have been on it forever it seems and I love it. However, there are months/days when no matter what I do I can’t get my blood sugar to lower. On these days I use a needle and give myself a shot in the arm. I don’t do a ton of shots, however, when my body is acting funny I always gravitate to the needle to help my pump.
This may be one of those things that work well for some and less so for others, like Dexcom G6, some can restart and others it starts failing at 7 days.
There are reports of Fiasp causing occlusions and like you limited effect on the 3rd day. I am thinking that there may be a sort of partial occlusion causing the 3rd day issues. It may be the occlusion is more that because of inflammation or fibrosis in the tissue near the cannula is less willing to allow the absorption of insulin.
In 2022 Tandem acquired Capillary Biomedical who has been working on a really revolutionary redesign of sets from tubing to the cannula. The following video is rather long but really gives some good background on the history of sets, the problems with current designs and how Capillary Biomedical is attacking the issues. If Tandem can work out all the problems with a completely new method of infusing it will be a game changer. In any case this video gives a really good understanding of how sets fail.
I had one of the earlier Tandem pumps. It was so high by the third day, and I proved it, that they gave me a full pump refund around day 45. I documented my case, and I won my money back. My husband worked with enough pump type equipment to be able to figure out the design of their cartridge was causing too much insulin to not be moving out by the third day. I was glad they let me out of the deal, that was the four your commitment I was not willing to make.
Yeah I’m SO looking forward to the release of this set. One thing I really didn’t like about the switch from Medtronic was that the Minimed Advance inset, particularly the inserter, is a big improvement on the old-school Mio thwack-and-puncture thing. It just seems to get the cannula in without nearly as much trauma to the dermis. I’ve thought that may be another possible cause of the problem I’m having. More inflammation = worse absorption.
I actually have a couple boxes of Advance insets left, and I tried using them. The inset-connectors on the Advance and Autosoft XC are the same, but the reservoir connectors are incompatible. So I tried inserting the Advance inset and reusing the tubing from the Tandem. Worked fine the first time, but not the second—lots of occlusions. You can cannibalize the tube from a fresh XC inset but then you’ve rendered it worthless. So either way you end up basically wasting an inset for each site change. Why can’t these bastids use a universal Luer-lock connector?
From what I recall from previous posts of Tandem users who are using Fiasp is occlusions are very common on day three. I use Humalog or the bio similar that my insurance pays for with no “day 3 blues” however if I go over three days then definitely I start getting highs. This is most likely in my case a combination of inflammation and possibly using the sort of same site too much. I do rotate of course but my skin reacts badly to insulin as far as I can tell since my Dexcom sites don’t get irritated. This happens with MDI as well.
I use Fiasp in my Omnipod Dash. Haven’t had too many issues over the past 1.5 yrs, takes longer than I think sometimes but could be we just need a little more patience.
I have the exact same issue. I have a Tandem TSlim and use Fiasp as well and I am certain it is because of the reasons that @Luis3 mentions. I pull all the air out of the TSlim vacuum cartridge with an empty syringe before filling it with insulin. This helps. The long highs will subside if you change your site earlier once you notice it creeping up. Once your BGs start staying up and the CIQ and 1st Round bolusing doesn’t bring them down, switch your cannula (you can keep the cartridge - just remember to fill the new cannula before resuming insulin). The longer you wait to change your site, the longer you go without the basal insulin absorbing correctly & the longer BG high you will have which takes a loooooooooong time to come down to the normal range. The 3rd Day highs are not predictable enough for me to have a regular schedule of loading less insulin to change site earlier. I usually get 3 days out if it.
I use Novolog in my pump. I have the same issue at Day 3 to 4. I use about 28 units a day.
I used to fill it up to 225 unit so I would not have to switch it out as often. Between day 3 to 4, and /or with less than 30 units I would some times would get those stubborn highs. I would bolus and exercise and it would barely come down. Sometimes, the needle would come out, but I check it more often now. Change the set to similar location and the sugar comes down right away. I alert myself to 30 units or less ,monitor and change after 3 days.
I wonder if this is by design to stop users for wearing the set to long.
I’ve never used a Tandem pump but think this issue is likely more widespread than that brand of pump. I’ve had similar experiences with the Omnipod and more limited with an older Medtronic pump.
I suspect the underlying and common issue is of insulin absorption. Once the absorption is impaired the basal deficit accumulates and it takes a large amount of insulin and time to bring things around.
I don’t mean to downplay the propensity of certain technologies combined with certain individuals to suffer from this phenomena. The antidote to this, at least for me, is to be ever watchful for unexplained glucose rising in a steady and relentless fashion.
When I occasionally experience this scenario, it’s inevitably on the third day of an infusion site. I’ll change the site immediately and the problem is often fixed. For me, quick action is the key. I don’t know what I’d do without a CGM!
Same. Fiasp or Lyumjev is the same at day 3 – loss of efficacy & site irritation (Lyumjev) – hardly worth the benefit. I heard from Tandem that the TSlim pump is not set up for super-fast acting insulins meaning the algorithms will be a bit off as well as the rate of injection down to the calculations for ISF and Control IQ corrections. For these reasons, I stopped using Fiasp and went back to Novolog.
This question is no doubt considerably off this topic, but I didn’t see a conversation that was better.
I use a t:slim pump, and have done so for 4 years now. As a backup system (which I haven’t ever needed, fortunately) I keep a kit that has the Tandem t:Flex pump that i used immediately before getting the t:slim.
The insulin cartridges I keep with this T:Flex emergency kit are “official” T:Flex cartridges, but they are considerably past their expiration date.
Today, as I was changing my t:slim cartridges, I mused on whether the t:slim cartridge would fit and work in the t:flex pump. Comparing the two cartridges, it looks like it would.
Is it possible that anyone here has tried this, and if so, did it work?
