Using an Infusion Set Longer Than 3 Days

Using an infusion set longer than 3 days???

“The FDA approved on Friday a proposed trial of an insulin infusion set that can be worn for 7 days, according to a press release from Medtronic.”
That would cause so much trouble for me. If I use an infusion set more than three days, the insulin absorption is not as good. Scar tissue can begin to form. If I used the set for seven days, I would probably get very little absorption. Scar tissue can remain in the area for a long time, and there might be poor absorption after applying a set at the same location later on. Doesn’t Medtronic and the FDA know about scar tissue?

What are your thoughts on this topic?


Shear lunacy. :crazy_face:


I’ll believe it when not only the stage III clinical trial data come back in, but also when the subsequent wider market takes these sets for an (extended) test drive.

Remember those “FlowSmart” BD sets that were close to being released a while back with multiple holes for outflow? The whole selling point was that they’d be impervious to occlusions and potentially allow longer wear. They were released and then they found that the sets actually had more problems than others.

The sets were reeled back in with the claim that they’d be rereleased eventually. They were canceled last year.

So, yeah, not optimistic.


We only get 2 days on an infusion set before poor absorption sets in. I would love it, if it worked, but I suspect that it won’t.


Can you imagine the itch? A hot red inflamed puss infected oozing pump site that tingles you all night long… Sales Team - A CGM can do 7-10 days what’s wrong R&D, man up, deliver us a 7 day pump site to sell… Just the reason i dumped the pump after 20 years and went to Tresiba.


I can barely get past 24 hours with a set. If I’m lucky, one might last 48 hours. I basically have to re-use metal sets because otherwise the maximum amount provided by provincial coverage (five boxes every 90 days) wouldn’t be enough to last me through. Luckily, it’s fairly easy to re-use metal sets once (I haven’t had the greatest luck trying to re-use them a second time).


Medtronic said its longer-use system will address these issues with “new adhesive technology” and the aim of ensuring that insulin delivery remains stable.

That’s all? How are they going to make this infusion set occlusion-resistant? Another issue is that the infusion site will itch like madness after 7 days.


Medtronic has been saying for a while that they want to develop a unified sensor+infusion set, which they think will be more attractive to loopers than separate sensor and infusion sets. A long-duration infusion set would be a step in this direction.

I’m guessing that the short-term pivotal study will show that the 7-day infusion set works fine, so it will be approved. And then some years later we will find that a significant number of the users have developed scarring that makes it difficult for them to find any workable infusion site.

The key question is whether the problem with long-duration infusion sites is something to do with the cannula, which a new set could possibly fix, or something to do with repeated insult to the local sub-Q tissue by insulin, which would seem to doom the prospects for long-term infusion sets in the absence of a more significant advancement. Non-irritating insulin re-formulation? Steroid-eluting cannula? There are possibilities, but they don’t seem close at hand.

Maybe what we need is a return to implanted pumps that dispense directly into the portal vein. Now that advancement would really enable good closed looping.


Interesting! Do you know more about this? I would expect the insulin to disturb the glucose concentration locally, causing inaccurate BG measurements.

It really depends on how far you separate the sensor from the infusion site. Not a workable solution, but what if when you inserted the site, the sensor went in a different direction far enough from the infusion site to work.

Then you still need two needles, simultaneously inserted at different angles. That sounds quite difficult and error-prone to me. If the infusion site fails, both need to be replaced. Personally, I don’t see the advantage of that.

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Oh, dear. I don’t remember where I saw it, but probably it was the Minimed Duo that was approved (and apparently not commercially sucessful) back in 2014-2015.

This URL really does point to the Medtronic press release for the Minimed Duo, although the forum software is showing a wrong image and description here:

And a mention in a description of (then) new diabetes technology:

And a technical paper about it:


i changed my Medtronic infusion site every other day. Medicare used to cover this and supply all pump needs at 100% (no cost to me). very conveinient.

last year, Medicare decided to change their policy and would only approve a change every 3rd day. if i wanted to change my set out as usual, i would have to pay out of pocket. i had my endo write endless letters, endorsing my need for the 2 day infusion change. nothing has happend and its been a year of trials now.

i have found that i get completely different results from the more frequent site changes. i am very skinny in the tummy area, and scar tissue can easily become an issue if i wait longer than the 2 days. currently, i am paying oop for the cannulas. i am still keeping my fingers crossed regarding Medicare. my endo is veracious and continues to try and get approval for the site changes. :crossed_fingers:


how do you make sure they’re sterile the second time? Do you just clean them with an alcohol swab?

I cannot believe I never thought of reusing a steel infusion set. Learn something new every day here!

Usually I just try to make sure the needle doesn’t touch anything. If it does, I sometimes wipe it with an alcohol swab (though that’s hard for me to do) but most often just don’t use that one again. Since I’m most often changing the set out after only wearing it for 24 hours, I feel like it’s less risky than if a set were staying in for a full three days and then reusing (which I don’t think I’d do).

It’s not ideal—greater risk of infection, requires re-taping, and the re-used sets do seem to fail more often—but I started doing it during a time I was having to change sites every 12 hours, because using a new one just seemed so wasteful (plus, as mentioned, I literally didn’t have enough to change that often). I can’t say I’d be doing it if I didn’t need to, because I find it annoying, but who knows.

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I have always been able to use infusion sets for ages, with good absorption and no infections. After 41y of T1D I don’t have any appreciable scar tissue (in my pumping area). I have been pumping for 20 years this December.
When I was a student, and had to pay full price for my cannulae sets, I could get up to 10-14 days. No itch, no pus.
I routinely go 5 days now, easily. And using my looping app (Android Artificial Pancreas System), I can see if I start getting resistance. I don’t.
I can also wear Dex G5s for up to 49 days easily(and very accurately). Usually the adhesive lets go on my last tape change, so I have never quite made it to 50 days :roll_eyes:. Adults get no subsidy in my country, so most of us wear much longer than 7 days.
I firmly believe some people DON’T get all the scarring and reactions from cannulae and so on. Some do, and that is a thing. Some don’t, and that is also a thing. It’s a bummer that many people do have issues, but every time I have mentioned my lack of reaction, I am shouted down on forums. So I suspect quite a lot of people don’t have issues. Certainly in my local area, many people can extend their sets easily. Some can’t.
Seriously, I got far more scarring in my arms and thighs when I was a kid injecting with needles. I pump almost exclusively in my lower belly. No lumps, no scarring, no marks.
Just saying… Oh, and I am medically trained - I understand and embrace the risks…


@Morrisminor72, I think that may very well be. The issue is that we don’t yet have a test or reliable way for people to know in advance if they’re the type of people who never get star tissue or lipohypertrophy or if they’re the type who will. And once you get it, it sucks, because it’s kinda there forever.

We change Samson’s sites every 3 days like clockwork. Occasionally for some reason we’ve missed it, and some days it’s been fine, and others it has very decidedly not. But he’s only 5 so he hopefully has 85+ years ahead of him, and it’s at least conceivable he’ll have to be injecting insulin in some form for all that time. So we play it safe with him and keep to the site rotation schedule.

But I sure would love if someone could do a test or find a way to identify a site that’s failing well before it actually causes hyperglycemia.


I am thinking you will get to find out how long Sampson’s sites last in approximately 8 years time :joy:. He will likely test every single bit of his D management to the max. Good luck with that!

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I’ve already instructed Liam to stop growing. 5 is where he has to stay. :smiley: