Silent occlusions just after changing set

I am having issues some hours after a change of my infusion set. Quite often (twice a month) I get highs and ketons few hours after the change (1 to 2 hours), and i need to have a bolus with a pen to restore the amount of insulin not absorbed from the moment of the change to that moment.

After removing the set, I see a drop of blood coming out of the skin from the insertion site; the bigger the drop, the faster and more severe the ketones.

I have been TD1 since 1982 with an acceptable control (7-7,5) and a I check my values 12 times a day, using a self-developed Statistical model to analyze the deviation from the standard and understand when the error is statistically significant.
I use a AcchuCkeck Spirit Combo with teflon FlexLink cannula (6 or 8mm, 90°).

Some cause I have already excluded are:

  • the cannula is not kinked when I take it out from the body, and if I try to pump through it, insulin flow out in the air.
  • insertion site is not compromised, I have it checked by doctors every 3 months and it has no signs or hardenings
  • i have tried Tenderlink sets as well, 12mm with manual insertion 45°
  • no bubbles are in the tubes when this happens. I have some drops of insulin pumped out from the tubes to check them before linking the tube to the cannula.
  • batteries and everything else in the pump works correctly
  • the problem may appear at anytime in the day, close or far from lunch, but always few hours after a change
  • I have tried pumping more insuling - instead of changing the set and using a pen - and the highs and ketones don’t get solved that way. The problem seems to be in the body/set connection.



I also am on the Spirit combo. Started off with cannulas and had problems with them. Would alarm at every bolus. Frustrating. My husband has been on pump for 35 years and has always used steel needles. Decided to give them a shot and I haven’t gone back. Best thing is, in a pinch, I can remove and re-insert temporarily if I have to.

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I’m on the Accu-chek Spirit also. I use the Ultraflex infusion sets, 8 mm cannula. I use their inserter. I can’t remember the last time I had a kinked cannula. I do a little bolus just after changing sets, and a correction if needed.

my problem is not with kinked cannula. The cannula is perfectly inserted and straight, but it is like no insulin is coming out due to the blood pressure in the capillary, or something similar.

hmm. maybe you are inserting into areas with impaired absorption. does this happen every time? have you gotten any suggestions from your endo or cde?

the steel set from accu-chek is called the rapid-d. perhaps you can call their customer service and ask for a sample.

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Some of my sites seem to need to absorb a bit more insulin and are slow to start so I setup a higher temp basil rate just after inserting new set. I usually make it 1-2 hrs long and just a bit more insulin than normally set for those hours and it usually starts working fine once that temp basil rate expires.

For me, high blood sugar plus high ketones is a sign that a site is not working, and I’ll change it to a completely different location. I’ve tried just moving the same set and inch or two, since I use metal sets, but I find that may resolve the ketones but not the high all that well.

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There are several credible explanations for this. Your situation with a non-kinked cannula and a set that can easily deliver insulin through the cannula tip once removed leads me to suspect that your site tissue, for one reason or another is not absorbing the insulin. I’ve read that the immune system, in an attempt to fight the introduction of foreign material into the body, may respond to wall-off the cannula and block insulin flow.

Another explanation is lipohypertrophy. Here’s the definition from Wikipedia:

Lipohypertrophy[1] is a medical term that refers to a lump under the skin caused by accumulation of extra fat at the site of many subcutaneous injections of insulin. It may be unsightly, mildly painful, and may change the timing or completeness of insulin action. It is a common, minor, chronic complication of diabetes mellitus.

I know you said that neither you nor your doctor can feel any lumps under your skin. I went through a period where my abdominal sites start to fairly consistently give me absorption problems. I couldn’t feel any obvious lumps either so I’m thinking that lipohypertrophy may exhibit a range of symptoms and even the milder cases may cause insulin absoprtion problems.

I stopped using my abdomen for infusion sites for over four years. I even went to a physical therapist to try and rehabilitate my tissue. They used massage, ultrasound, and tens unit electrical stimulation on my abdomen. I’ve just started now, four years later, to return to my abdomen infusion sites and they seem to be working OK.

I think systematic site rotation is a worthwhile practice. It’s likely better than the crude “left-right” system I used.

Like others have suggested, I think it’s a good idea to change the style of infusion sets from time to time to help prevent site non-absorption. Good luck. Please report back if you find a good solution for yourself.

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I also use the spirit combo. I also have been having absorption problems. Mine don’t usually start until day three. The last month I have been changing every two days and it’s been working pretty good. I did get some rapid d sets from Roche and am getting ready to give them a try. I used them a few years back when they tried to redesign the ultra flex sets and they didn’t work out. Ultra flex weren’t available for a period of time. Seems like I had good success with the rapid d.

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Thanks for your contributions.

I do a systematic site rotation using my abdomen and gluteus. The strange thing is that I may have silent occlusions at the first time I use a site after month, while in another site I can have a silent occlusion in a spot and everything works fine just a few inches away.

Everything seems related to how close I hit a capillary. During some silent occlusions I tried to press the cannula with my fingers and the site hurted a bit, like a little pinch, and lot of blood went out when I removed the cannula.

In these days i am reading some articles about the new BD FlowSmart which includes a “side-ported catheter”, I wonder if that might work to solve this and i will contact my doctors to see if I can have it.

I also have some episodes after day 3 (actually day 2.5 in my gluteus, day 3+ in my abdomen), but those come up slowly and are not so severe like when in happens just after a change (in my estimates, insulin absorption is about 50-70% in a silent occlusion after 3 days, 0-10% in an immediate silent occlusion).

we had a very popular topic here a while back “Do you have problems on the third day” you might find interesting

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