Infusion set change

By | 14 December, 2010

Tim’s introduction: for your fun and entertainment regular reader Stephen has documented – with pictures in glorious Technicolor(TM) – the process of an insulin pump infusion set change. Enjoy!

Stephen’s introduction: Let me start off by giving you plenty of warning about the following content. The article contains some graphic content of my hairy wobbly belly. It has been known to make women go weak at the knees (with nausea) so those with a weak constitution may want to turn away now! I hope this article gives the non pumpers an idea of what is involved in changing an infusion set, and existing pumpers who haven’t seen the mio set before an idea of what it’s all about. Comments and criticisms are always welcome in the comments below!

Every three days the infusion set and reservoir need to be replaced. Primarily you run dry if you don’t (and going cold turkey on insulin tends to be pretty hard,) but equally important is if you use them for any longer you run the risk of getting a nice little infection and that would presumably be rather unpleasant.

Whilst still hooked up to the old set, I get things under way by filling the new reservoir. This is the almost syringe looking device that holds the insulin inside the pump. Medtronic reservoirs comes in two sizes, the 1.7ml (works in the both size pumps) and the 3ml (only works in the 7XX pump.)

Here in all their glory (left to right) are the 1.7ml reservoir, 3ml reservoir (with clever filling device on top) and 10ml insulin vial. Each new reservoir comes with a new filling device and should be disposed of (in a sharps bin/council estate/lake) once the change is complete.

Filling the reservoir is just like filling a syringe, and can be just as frustrating. Air bubbles are not tolerated! The problem is if air is in the tube and the pump thinks it’s giving you X units, the air bubbles would mean it actually gives you less. The vial just pushes on to the top of the filling device and after 5 minutes of drawing it up, pushing it back in, flicking it (and if all else fails banging it on the table,) you should end up with a nicely filled reservoir in this sort of arrangement.

Obviously it’s not going near the pump like this so after pulling the vial off, unscrewing the plunger and twisting the filling device off, the reservoir is ready to go.

The mio itself is an all in one unit so there’s no need for a separate inserter. This might bother people who like to put their own sets in manually but as I’ve never tried that it hasn’t bothered me. Each box of ten comes with two little covers that can be used when you want to disconnect yourself from your pump (or make Christmas baubles) but I haven’t been told to use these or felt the need to yet.

Popping off the lid of the mio reveals the business end of things. In the middle are the insertion needle (with protective cover) and the infusion patch itself. Unraveling the tubing give you access to the connector that the reservoir just twist locks into. It only fits in once way, and only twists one way so there’s pretty much no chance of messing that bit up.

For those interested this is a 6mm set (how deep in it goes) with a 45cm (18 inch) tube length. I find this is just right for dropping in my trouser pockets, though I suspect the ladies might have difficulty reaching their cleavage comfortably with this. (Having not tried I stand to be corrected on this one.)

I did take a lot of pictures of the next bit, but I suspect 8 photos of the pump screen with different messages on them might be a bit boring! You now have to tell the pump you are ready to change things. This flows as follows:

  • Select Reservoir + Set / Reservoir Setup from the pump menu.
  • The pump now prompts you to disconnect yourself (more on this later) and remove the old reservoir. This unscrews out of the pump leaving you with the tubing and reservoir to dispose of.
  • The pump now rewinds its plunger all the way back in.
  • Once this is complete it asks you to put the new reservoir in, again it just twists into the hole designed for it.
  • SANITY CHECK: The pump asks you if you are disconnected from it. In the next step you are going to fill the tubing (priming,) so you don’t want to be attached at this point else you might end up with too much insulin.
  • Holding ACT on the pump now starts to push insulin down the tube. In my set I normally push about 8U and make sure a good couple of drops have come out of the end of the tube (see picture) and that no pesky air bubbles have found their way into the tubing. If they have, keep on pushing! I believe the Medtronic has a 75U limit on priming the tube but to be fair if you’ve used this much then something’s probably wrong somewhere else.

Once you’re at this point, there’s no escaping the next bit. Connecting the set to you! Granted I’ve only been doing these for four weeks, but I still sit there and squirm a little bit when the message pops up on the screen. What I can tell you though is I haven’t had a single insertion hurt me so far. The worst part of the whole process is the noise!

Start off by removing the tape cover (like the back of a sticky plaster) from the mio to reveal the sticky surface, and the large paper cover off the other side to reveal the firing mechanism.

The mio is armed by pulling the handle-looking thing in the centre up and out (it rotates as you pull,) until it clicks into place in both sides. The last thing to remember (and I can only assume it’s going to hurt if you forget!) is to remove the protective cover from the insertion needle back on the other side. The tubing as you can see sits in a little notch in the mios body so you can get a flush contact with your insertion site.

Warning: Impending belly shots

The mio does require you to push the contact patches quite hard to get it to fire (which I guess prevents anything happening prematurely.) There are two circular patches on the body of the mio that you have to push, and if like me you have your tubing coming out the side of the site then you have to twist your hand round a bit awkwardly to get a decent grip on them. A firm squeeze, followed by a CLICK-CLICK and a THUNK (makes me jump every time) and the set is in.



You can push down on the handle now just to make sure the patch has a good contact with your skin. It doesn’t hurt and doesn’t seem to push the needle in any further. I think it’s just good practice to make sure the patch is holding, as there’s a slight risk of pulling it off in the next step.

Carefully pull the mio upwards by the handle. This withdraws the needle from your body but leaves the cannula behind. The needle will be exposed now so dispose of in your chosen method. The white innards can be pushed out from the blue outer if you are as nuts as me about recycling! Push from the handle side down where it connects on the outer edge and it will pop out.

The end result is a hopefully connected infusion site. Here’s a gratuitous belly picture with a penny for comparison. A 2p would have been better admittedly …

Remember earlier I talk about disconnecting from the pump? Well the blue connector detaches from the site. Squeezing the knobly bits in at the side allows you to slide the connector off, and push it back on (it has a definite click to let you know it’s connected,) as appropriate.

The final step back on the pump is to fill the cannula; this is just pushing a small amount of insulin down the tube. For a 6mm set this is 0.3U.

I’m sure the experienced pumpers can add an awful lot of tricks and things to this, but I think this covers the basics. Some pictures of other cannulas would be really good too!

Here’s a couple of reference pictures that I tried hard to find on the Internet before I started pumping but couldn’t!

A used mio:

A used cannula:

11 thoughts on “Infusion set change

  1. Tim

    You are demanding Mike! I’m planning a new vblog, but I’ve only got about an hour of daylight in which I can do it at the minute, so it’s proving difficult to do!

  2. Mike

    I am correcto! 🙂 Will try and send a bit of light your way soon..

  3. Cecile

    Years of shady conjecture (about pumps & male abdomens) lit up by your bits of picturesque enlightenment…Thanks & No thank you 😉 (And I see your reunion with something from years back {vials} have made you grab for a rectangular glass of cloudy NPH?)

  4. Alison

    I would have commented earlier Stephen but I’m still swooning from the belly shots 😉

    Thanks for doing this, I’ve been meaning to for years but I don’t have the patience to document the process and I don’t fancy publishing shots of my belly/leg/bum on the internet!

    Those spare cap thingys you get with each set are for you to put on it when you disconnect to save leaving the set exposed. That’s the theory. In practice I’ve never used one yet.

    You’re not alone with the sqirming, I’ve been at this nearly 4 years and I still cringe at the clunk noise whenever I insert a set or a sensor!

  5. Stephen Post author

    Sorry for any discomfort there @alison, my wife did question the harm I might cause by putting those photos on the interweb …. she loves me really!

    Yeah the caps seem pretty useless, I think @annette ‘s use was much better (even if she insults me for complimenting them 😛 )

    The sen-serter or whatever it’s called for the CGM looks even scarier and louder to me! I’m going to try and document that after Xmas …. really want to get on with it NOW but I promised the rep I would wait 🙂 Tuesday isn’t that far I guess!

  6. Alison

    The inserter for the CGM sensor reminds me of a harpoon, but don’t let that put you off, it looks worse than it is!

  7. katherine cromwell

    Great info! Like the idea of christmas decoration usage. Do you think they’re puppy proof? Training pup at mo not to jump and pull out tubing!!!! A few choice words said at the time. Pup will learn haven’t tried squirting it with insulin yet though.

  8. Hairy Gnome

    Well, that was very enlightening. All I can say is that the benefits of using a pump must be considerable, ‘coz just reading about all that left me feeling vaguely nauseous. Not the hairy belly shots I hasten to add, at the risk of giving too much information my belly is bigger and hairier, it’s something to do with the mechanics of it all. My respect for you pumpers keeps being revised upwards! 😀

  9. Tim

    @teloz – you’re being overgenerous – sticking in a infusion set is actually a piece of piss. In fact, I prefer doing them to injections.


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