Bent cannula

I’ve only been on the pump now 3 weeks. At first I had no problems but yesterday evening after changing the infusion site, 2 hours later my BS was 240. I went to bed but got up at 3 a.m. to check it and it was 400! I immediately changed the site and sure enough the cannula was all bent. I put on a new site (in the same spot) gave a bolus and went to bed. 3 hours later when I got up it was 420!!
I changed the site again and once again, bent cannula.
This time I put the infusion site in a totally different spot. I know I’m doing it right. Why does this happen and why doesn’t the T4 Slim give an alert for no delivery??

I would suggest not doing pump sites at night. For that exact reason!

I am not sure the sensitivity level of the Tslim…but it usually requires at least a unit or two before the Medtronic occlusion alarm(No Delivery) will go off. Depending on your basal rate, it may take awhile. Which is why I prefer to do site changes during the day when I know I am going to be bolusing soon, or if I see a trend going up that I shouldn’t be seeing.

Some areas are just not great to put sites in, even if you think it may work. I can’t ever do a straight 90 degree set in my stomach. I am almost guaranteed to get a No Delivery alarm there. I’ve just learned over time what spots to use, and not use. Sounds like wherever you were trying you may not have enough fat there, or it’s too much muscle. I would try either a different set there (angled) or not use it all together.

I don’t really understand what people mean when they say angled. I use the little round insertion kit that you just place on your stomach and squeeze the sides and it injects it in for you…like it’s spring loaded…

Some cannulae are inserted at 90 degrees, and others are inserted at 45 degrees. For example, the OmniPod’s cannula is automatically inserted at about 45 degrees in relation to the surface of the skin.

Someone please correct me if I’m wrong and there are other angles. I realize that with self-insertion you could insert at angles shallower than 45 degrees, but I suspect this would negatively impact insulin absorption.

Folks who frequently experience bent cannulae often have better luck with steel sets.

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If you are using an inserter, most likely you’re using a 90-degree set. I think the only angled set that works with an inserter is the Inset 30. I agree with others not to change sets before bed due to the risk of a bent cannula.

But one other thing you may consider is using steel needle sets. These sets do require manual insertion and, while some people hate them, most people who have tried them love them. Since a needle can’t bend, the chances of having a “bad” site are dramatically decreased (although it can still happen on occasion in my experience). The downside of these sets is that you have to change them more often than the sets with a flexible cannula.

It sounds as though you are using a 90 degree set meaning that the cannula goes straight in. Maybe an Inset, Quickset, or Mio.

An angled set is something like a Silhouette or Comfort and many people insert these manually. They are put in at an angle somewhere between 25-45 degrees. The insertion can be daunting but for me it has always been worth it. I do not get bent sets and rarely failures (at most once a year and probably not that often). There is also an angled set called the Inset 30 which has an inserter as part of the set, but I always found it a little too complex to deal with and I didn’t trust it as much as manual insertion.

Whenever I have tried the 90 degree sets, I get a much higher rate of failure and a high rate of painful sites. Every time a new 90 degree set comes out, I try it because of the inverters or cute colors. I always end up back at Silhouettes/Comfort Shorts. Silhouettes are the Medtronic version. Comforts and Inset 30’s are for other pumps and that would include Tandem. Please note that Comforts come in two lengths. I use the shorter ones.

Frank, a young Australian blogger, recently wrote about switching to an angled set. I was one of several readers who kept telling him to try them and I am even mentioned in his post.

Bent cannula can sometimes happen. It has happened to me maybe 3 times in 30 years. Mal-absorption is uncommon but rarely due to bent cannula. It is important to figure out which sets work for you. The improvements in sets in the last 30 years are cannula (metal are evil), disconnect at site & tubing that resists crimping.

BTW: infusion are not made by pump manufactures. As long as there is a luer lock twist on connection it can be used on any pump with a similar connection. Many years ago I was told that there was only one manafacturer of sets & they were in Denmark.

Don’t give up. Pumps have benefits that are not possible with MDI.

I was having similar problems with my Animas Insets and think it was that I was pressing too hard against my skin when I was inserting. After thinking that was it, I’ve been careful to just place the insert on my skin without pressing and haven’t had another one…crossing fingers that it stays that way!

I experienced the same problems 4 years ago when I first started pumping. I had three or 4 bent cannulas in a row. I called my pump manufacturer’s service line and asked for samples of different types of sets. They sent to me two of each type they had. After trying them all I chose their (Medtronic’s) Silhouette set and have not had a problem since.

I believe that every pump maker offers the same basic set types. The Medtronic Silhouette is an angled set that can be inserted either manually or with an inserter, I choose to do it manually because the inserter reminds me of a harpoon gun and is quite daunting to use.

This is fairly common, all sites are not the same, lol. I have 4 sites that I use angled insertion sets and 4 sites that I use Straight. Angled are for areas where fat is not so deep.

For me, a big problem with a bent cannula is that you don’t know how much basal insulin you missed. So when you take a correction bolus calculated for the high, you are still short insulin from the basal. Maybe you missed the entire basal amount for those hours; maybe you got some portion of it. It can take multiple corrections and lots of testing to eventually get it right. Or you can be more aggressive and be prepared to handle a low. Missing the basal insulin may be what caused the high, but you are still missing insulin that is supposed to be there but wouldn’t have taken effect yet.

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Are you inserting the set while sitting down? Years ago, I found that I would have site issues if I did. Now, I stand while inserting and have had many fewer issues.

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No I definitely stand up, it’s much easier for me that way. I’m only 5 foot tall and rather short waisted, so I just found it easier to stand. I talked to the diabetes educator today and he seemed to think that it may have happened because I didn’t pull the needle out straight after the cannula went in. He said if I pull it out at an angle at all, it will cause the cannula to bend. Could very well be what happened…

Don’t over think this. You know your blood sugar at the moment. The calculation is what will get me back where I need to be. If there is insulin infused but not absorbed then correct when it is apparent. Test BS every 30 minutes so you can detect a dropping BS. Most times I won’t see a change for 30 min to 1 hour. A BS test is a measurement in time. What is more important is the trend (delta).

When I was new to pumps, I used to have more bent cannulas and had the same experience as you. I would suggest checking your BG 1 1/2 hours after a new set, if it is high then, wait an hour after a bolus and THEN if it is high after two blood sugar readings, change out your set, you could still use the same vial of insulin, and a new insertion set with tubing.
Never go to bed with a really high reading, unless it has shown through finger pricks or your CGM that it is coming down.

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Back when I first started pumping, metal infusions set were all we had. Than I switched to Teflon and got a lot more days out of each one. Money saver! Metal needed to be changed every 3 days. I was with Minimed (Medtronic) for around 24 years and switched to Tandem 2 years ago. I also had more occlusion alarms and bent canulas. Did a quick review with pump trainer and she gave me different infusion sets to try. I have been using the comfort detach metal infusion set and have had no issues since. I do have the three day alarm set on the pump to remind me to change every three days. I have never had an infection due to infusion set being in to long and hope it stays that way. I also insert old school and have never been comfortable with insertion devices many companies make. Not sure if that might also be a possibility for you. Good luck and I would call and ask about some samples. There are many out there and I think it’s BD that has a new one coming soon that has more openings in the canula for less possible blockage.

That would definitely happen if you pull it out at an angle. Also, be sure to put all your weight on the leg that is not receiving the cannula (if using your leg or buttocks).

Having the same persisting troubles with a Tandem T-slim now in the sixth month. Using a 6mm, 90 degree insertion cannula since body fat is low but what I suspect is when removing the guiding needle, the entire canula slightly lifts because there’s just a weak bond on the tape holding it in place even though I do use an adhesive like Mastisol and the canula gets secured now without the guiding needle which causes a bend at the very bottom while pushing the securing patch in place. Thankfully, the Dexcom G6 will reveal BS numbers in the pump but this has happened at least 3 dozen times in 6 months and seems like a Tandem defect to at the very least, not sound an occlusion alarm for no delivery. 51 years type 1, 30 on pumps so while technology’s never been better, this persisting troubles made for extreme frustration. It’s become like a crap shoot causing constant suspicion.

I was told when I had a bent needle using Tandem’s Slim 2x auto soft 30 infusion set that because I have had diabetes for over 60 years, pumping for 20 of those 60 there is probably a lot of scar tissue on my abdomen. Tandem suggested I try the Tru Steel infusion set however I love the automatic insertion device the Soft 30 comes with so I’m sticking with the 30. I was using Medtronic’s silhouette with my old pump and seldom had problems. I’m new to Tandem and only had one bent needle. I also put the infusion set on a virgin area of skin. That also seems to be the answer.

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