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Cannula stops working during use?

C

claire mccann

Active Member
Hi I wasn’t sure if anyone else had this problem-a few days into use the cannula seems to stop absorbing the insulin into me or at least decreases absorption rate significantly? I notice because I need 3*as much insulin but then when i take it out it all seems fine and insulin flows normally?

I use medtronic 640g and minimed mio cannulas

Thanks
Claire
 
Yep all the time. Drove us all mad. Will only use sure t now. Needs a change every 2 days but i know it will work 100% of time
 
I have gone as many as 6 days with a cannula but I do usually change after 4 days - I don’t have another need to change sooner unless it’s to adhere to medtronic guidance which cynically I suspect is due to the companies wanting regular purchase rather than a genuine need (suppose it’s a bit like lancets)
 
When I was getting set up with my pump my DSN drove home that I had to change my canula every 3 days. The main reason being that your body will start to heal around the canula and so the insulin adsorption will drop dramatically. I have left my canula in for 4 days a couple of times when I was camping and it was a bit awkward to try and change it, and I did see a big unexpected increase in my blood glucose. So now I am strict about it!
 
claire mccann said:
I have gone as many as 6 days with a cannula but I do usually change after 4 days - I don’t have another need to change sooner unless it’s to adhere to medtronic guidance which cynically I suspect is due to the companies wanting regular purchase rather than a genuine need (suppose it’s a bit like lancets)
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I think your experience with having problems with insulin delivery when using the cannulas for longer than they are advised to be used might prove your cynicism about the guidance wrong - and on an economic view the I don't really think it makes a lot of difference profit wise to Medtronic whether the cannulas are used for 2-3 days or 6-7, they aren't high cost items. It shouldn't really be a suprise that sites that are being used for twice the time period they are supposed to be used for don't work as effectively. Using your sites for longer than the advised period increases your risk of infection and lipohypertrophy. When I was using Medtronic I would leave my sites in for much longer than 3 days purely out of laziness, I very rarely noticed any issues with effectiveness of insulin delivery/absorption, but when I did I definitely made sure to change my site.
 
I was a medtronic pump user and was told by the DNS and the medtronic nurse of changing sites every 2-3 days as the longer you leave it the more chance of a build up of insulin which if you run your fingers over you can feel a lump. They also told me to have 3-4 sites so you are not putting it in the same area and if the build up of insulin stops all the insulin going in the pumps should alarm or it has been known to come out on to the skin so you think you have had your dose but you have not had the full amount. I am sure if you change your sites every 2-3 days it will help and it is still better that having at least 4 injections a day.
 
Thank you all-I hasn’t realised the piece about cannula stopping working-I’ll change it sooner now. Just need to work out the impact of colder air and Pump being more exposed to it than say insulin in handbag and impact on dose (I generally only have about 30-35 units max a day) to be completely sorted!

Thank you all
 
I was told the changing sites every 2-3 days came after years of American pump users ending up with scar tissue because they were leaving sets in much longer. I can go 4 days without issue and very occasionally I do for something such as feeling too ill to change or unexpected events that make doing a change awkward. Otherwise I change every 3 without fail and sooner if a site feels sore.
 
  1. MushyPeaBrain said:
    I was told the changing sites every 2-3 days came after years of American pump users ending up with scar tissue because they were leaving sets in much longer. I can go 4 days without issue and very occasionally I do for something such as feeling too ill to change or unexpected events that make doing a change awkward. Otherwise I change every 3 without fail and sooner if a site feels sore.
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    So what sets are you now using because in the past you had absorbtion issues?
 
iHs said:


  1. So what sets are you now using because in the past you had absorbtion issues?
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I'm still using Inset II 6mm but I don;t use my stomach at all and I also gained weight which made a huge difference. I didn't plan to gain the weight and if I ever slim down a bit I might find the absorption problems come back but for now it's all good.
 
I have had diabetes for 15 years ( since i was 2) now pump user for 7 never had a problem with cannulas but the last three weeks i have had to change almost everyday sometimes 3-4 times until one works as they are filling with blood every time , anyone know any reason why this may be happening? (yes i regularly change my sites and sites which are usually fine no longer are and are now causing me extreme pain affecting day to day life).
 
evelyn18 said:
I have had diabetes for 15 years ( since i was 2) now pump user for 7 never had a problem with cannulas but the last three weeks i have had to change almost everyday sometimes 3-4 times until one works as they are filling with blood every time , anyone know any reason why this may be happening? (yes i regularly change my sites and sites which are usually fine no longer are and are now causing me extreme pain affecting day to day life).
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Hi @evelyn18 and welcome

I can’t help with your question as I don’t use insulin, however I wanted to welcome you and also mention that you’ve posted on a 2 year old thread. You’d likely get more response if you open a new thread with your question.
 
Hi @evelyn18 As mentioned already it would be a good idea to move your query to a new thread.

What are your blood glucose levels like when this is happening ?
 
I get this in the last 6-8 hours before I change the infusion set. Dr's advice was that the site deteriorates to some degree. Options are to change it more frequently or just increase the basal/correction doses etc. BUT as I also take additional time for the new infusion set to bed in I prefer to cope with the extra need for insulin prior to changing set. In effect I get really good readings for about two days and the rest of the time I am making adjustments but not changing my basal rates over that time. It's a never ending story... At least there is now some acknowledgement that this happens. When I first complained it was insinuated that it was operator error and I must have been inserting then incorrectly. Now generally accepted.
 
Helen46 said:
I get this in the last 6-8 hours before I change the infusion set. Dr's advice was that the site deteriorates to some degree. Options are to change it more frequently or just increase the basal/correction doses etc. BUT as I also take additional time for the new infusion set to bed in I prefer to cope with the extra need for insulin prior to changing set. In effect I get really good readings for about two days and the rest of the time I am making adjustments but not changing my basal rates over that time. It's a never ending story... At least there is now some acknowledgement that this happens. When I first complained it was insinuated that it was operator error and I must have been inserting then incorrectly. Now generally accepted.
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If the cannula works well for 2 days, why not change it every 2 days instead of every 3? Medtronic does say to change cannulas every 2 or 3 days.
 
dancer said:
If the cannula works well for 2 days, why not change it every 2 days instead of every 3? Medtronic does say to change cannulas every 2 or 3 days.[/QUOTE
I also have a problem regarding insulin absorption immediately after a set change. On a bad day this can last for 4-6 hours so I either suffer similarly at the end (before I change set) or after. Neither of these are precise...sometimes takes longer than others. Devil and the deep blue sea! I also try and time my set change to the CGM sensor replacement otherwise: sensor change every 6 days, reservoir change every three days and infusion set change every two days . Helen
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@Helen46 have you tried using an increased temporary basal when you change a set? I use a decreased temp basal for 2 hours after changing sets which prevents me going hypo (I am insulin sensitive). I have read on the forum that some pump users require an increased basal to prevent hypers after a set change.
 
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