Pump Suspended Insulin due to Occlusion in Tubing

Hello Everyone,

I woke up around 8 am this morning, no alarm that I heard but one may have gone off, to find that my pump had suspended insulin delivery due to an occlusion. I'm on saline so fortunately did not go high. However I'm very concerned about this. According to the pump history it suspended delivery from 6:14 to around 8:14, 2 hours. If that had happened with insulin I could have been sky high and if it had happened for a longer period while I was sleeping much worse maybe.

I just pressed the button and it started insulin delivery again, checked the tubing, I can't see anything wrong. Was this simply caused by maybe sleeping on the tube? Has this happened to you? I'm not sure what caused this or what to do about it but I will be calling Tandem to try to figure it out.

The alarm should go on every 15 minutes if the basal delivery has stopped. Did you not hear them all? It’s quite loud.

Hi Anthony,

No I heard no alarm, and I don't think the normal alarms are very loud at all although I have them on high. I sleep through alarms all the time including dex which is much louder but that one usually does wake me. I'm wondering what caused this? My trainer said it is impossible, practically, for the tubing to cause something like this.

The alarm could have woken me eventually if it was continual but obviously if it was I slept through 2 hours of it!

Occasional occlusions are a pretty normal part of pump therapy. They usually occur in the cannula, under the skin. The cannula itself can become kinked, especially if it rides up the insertion needle before being inserted, or as a function of bodily movement. But the insulin can also crystallize and form obstructions, especially in the cannula where it interacts with bodily fluids. The t:slim seems to have a pretty sensitive occlusion sensor.

My approach is to resume delivery after one occlusion and to redo the infusion set after two. I find that I'm much more likely to have occlusions when I'm sitting and my midriff is scrunched up than when I'm standing.

I think you can choose what sort of alarm you want for occlusions, and other events.

It is very hard to kink or squeeze shut the tubing. Try it with the tubing the next time you replace some. But it's definitely not impossible.

Pumps do have pros and cons, and some of the things with which you're struggling are part of the reason some people prefer injections. For many of us, the pros of pumps outweigh the cons, but you'll ultimately have to decide whether that's the case for you. But I would urge you to suspend judgment for a few weeks while you try your best to live with the pump, and then decide (but figure out how long your window is for returning it, I think it may only be 30 days).

My window for returning is nearly over because I had to wait forever to get a training appointment. I'm not really worried about that except I'm thinking the omnipod would have been better for me, so then if I call right away I may be able to return it and get my insurance to pay for that instead. I paid no copay thank god because my deductible had been filled.

Suspending insulin delivery while I'm sleeping isn't a con that I'm willing to live with because it could be life threatening for me not to mention all the stress it causes. Obviously the alarm isn't loud enough, I didn't wake up for 2 hours and I have them all on the loudest setting. But I do have a problem sleeping through alarms.

The only reason I'm trying a pump is that I can't stand mdi fluctuations anymore, I want more stable bg and I want to be able to control my basal so I can get some semblance of my life back again. And I've tried everything, changing doses, basal test, everything, Nothing helps, none of my endo/cde input have helped much if at all and usually made things worse.

Well, I just spoke with someone at tandem and she said the return window is flexible. I can discuss all of these issues with the trainer on tuesday and decide what to do, whether I will go ahead with insulin and try or not. I probably will, but very cautiously, I'm not sure yet. btw, she said an occlusion can happen in the tubing from sleeping on it etc. and that that is more likely than an occlusion in the cannula- she doesn't have d or use a pump I believe but she tested the pump with saline and that happened to her- she had a longer tube and had to coil it up or something to sit at work and it caused an an occlusion. She also said call back later for more help from a tech who has d and uses the pump. Interesting that the tech I spoke with last night said he takes his pump off for several hours to surf and takes some long acting insulin during that period. If I didn't have all the mdi basal instability problems I might consider not sleeping with it but that was really one of the things I wanted it for: controlling dp and having better sleeping patterns.

All pumps have potential occlusion issues. The only guaranteed way to have basal insulin in your system while sleeping is to inject a long-acting insulin like Lantus.

You said you'd tried everything to get your BGs under control. Does that include changing your diet/lifestyle? Maybe it's a dumb question, but I ask because there are some diets/lifestyles that are inherently going to be hard to control with insulin, whether injected or via pump.

If you think you'd prefer the OmniPod, it'll always bug you and you'll wish you'd gotten it. So I say get it. It may not live up to your hopes, but perhaps it will, and regardless you won't be left wondering how much better things might have been for you. My two cents, anyway.

lol, Yes dumb question- I have done tons with diet, just read some of my other posts here and my profile. I eat low carb and eliminated tons of foods entirely. My bg is "controlled" but still not stable if you get my point- hence trying a pump. Unfortunately diet is never going to be a magic bullet for some of us, I could eat broccoli all day and there would still be problems, even at 30g a day I was fluctuating all over the place but not as bad as some people.

I'm not sure what I'm going to do yet but I will post back here when I do prolly.

I find it hard to imagine diffuse body pressure on the tubing causing an occlusion. Try it with some old tubing. I cannot cause an occlusion even with focused finger pressure. Maybe if your body caused the tubing to kink at a sharp angle, but I think you'd have to work hard to make that happen. Same for coiling. I hate to say it, but that rep sounds way off base.

Well, you know what they say, nearly anything is possible in the right circumstances, so never say never. I think it would be poor design to use tubing that could easily become occluded in an insulin pump or anything like that. I don't know what to think about what she told me however I will believe it happened to her or she thinks it did, surely she discussed it with other tandem employees- anyway I will ask the next time I call again. I since discovered there were 4 alarms total, 2 at 6:14 am and 2 at 8:12 am when I woke up. I wonder if this was a continuous alarm or just 4 separate alarms and if it was off the whole time? 4 separate alarms wouldn't be enough imo for suspension of insulin and it needs to be much louder also.

Try it yourself. I'm just saying I cannot compress the tubing even if I use a finger and put a lot of pressure on it. I can, however, obstruct the tubing by kinking it at a sharp angle. But it really, really doesn't want to go along, so this shouldn't happen easily by accident.

I've had a few occlusions so far. One was a kinked cannula under the skin, apparently due to poor insertion technique (letting the cannula slip forward on the needle before auto-inserting). The others I was unable to diagnose, but as best I can tell there was either insulin crystalization or some other obstruction in the cannula or at its mouth into the body, though I certainly couldn't see it after removing it. The t:slim does have a rather sensitive occlusion alarm, but I tend to think that's a good thing.

I will try it on this one when I remove it- I already threw away the first one. What type of insets do you have? I have regular 90 degree with a huge plastic contraption to insert them so I don't think that could happen hopefully, although I did forget to remove the plastic thing on the needle when I was on the phone and the first time it didn't work. What type of insulin do you use? I'm not sure what you mean by sensitive? I would like a VERY loud alarm that will wake me up for any cut off of insulin supply. I'm pretty sound sensitive so I sleep with ear plugs and can't live without them now but the dex usually manages to wake me up at some point, often to tell me my bg is lower or higher than it actually is, lol.

When I'm in a deep sleep though it takes a lot to wake me.

I have the same ones you do--regular 90 degree ones. I was expecting to prefer the angled Comfort ones, since I'm fairly lean and athletic, but I found that while the Comforts were a tad more comfortable deeper in the tissue, at the skin surface the angled insertion caused a lot more disruption, so on balance I prefer the Insets.

You need to be very careful that the cannula (teflon sleeve over needle) doesn't slip up the needle before you insert it, because then it can kink. Visually look for the needle to stick out beyond the cannula before you insert.

I use Novolog.

By sensitive, I mean it seems to alarm easily, I suspect when there's only a modest occlusion. In my case, it's more likely to happen if I'm sitting and my abdomen is there's more scrunched up.

The angled one was painful so that was the end of that for me unfortunately because my cde said it was less likely to have kinking and other issues which may stop insulin flow. I thought we were supposed to remove that, I mean the plastic thing that protects the metal insertion needle... I haven't notice any other sleeve over the needle but if that is what you mean it actually prevented it from inserting the cannula properly last time.

I use Novolog also, hope I don't get those crystal issues. I see- I guess it doesn't always shut down the insulin supply then maybe? I wonder how long it was really shut off for in my case when it said insulin supply was suspended. I will ask the trainer on Tuesday too.

You're confusing several different things. From inside to out, there's a long steel needle, then a slightly shorter teflon cannula (the little plastic tube that stay inside your body, you can see it when you remove an infusion set after a few days), and then that plastic sleeve that you remove before insertion. You absolutely need to remove the plastic sleeve. But then you want to make sure the cannula isn't pulled forward on the needle, i.e. there's some needle sticking out beyond the cannula.

Novolog and Humalog are buffered, so they are far less likely to crystalize than Apidra is. That's why Apidra's not recomended, actually.

By sensitive, I mean if the insulin flow is only, say, 20 percent blocked, the pump will detect that and stop all insulin flow. When the pump says it has shut down insulin flow, you should absolutely take it at its word!

Hello, I've been away from this community for a long time. Just came back because I'm looking for help with exactly this problem. I have had the t:slim for about 2.5 years now, switched over from Animas mostly because of the aesthetics. Having lots of problems with occlusion alarms (using Novolog) but almost never had them with the Ping (what IS it with pump names?). I've been using the same tubing and infusion sets since 2005. For me the alarms have become a Peter-and-the-Wolf problem. Last night was an epic fail and it got dangerous. Luckily I was awake at the time. Trying to figure out what to do, and wondering if anyone else has these occlusion issues?

Hi Clemma,

Sorry you're having these problems. I had three situations so far but I managed them all with tandem phone help. I haven't had anymore occlusion alarms recently fortunately. The last problem I had was with a bent cannula but I didn't get any alert. My cde said due to my very small basal doses the pump won't alert if insulin infusion is blocked or low but it will alert with a larger bolus. Tandem pretty much confirmed this, so if the tubing looks ok and insulin is coming out I plan to automatically change the set, but not necessarily the tubing, if my bg is high/rising and there is no other explanation. As far as the alarms, I just hope this doesn't happen when I'm sleeping but if you change sets/cartridges etc. a few hours before sleeping hopefully you will notice before then. I would always consider doing an injection with your pens/syringes if your bg goes very high and the pump has an occlusion/situation that you can't fix rapidly. Fortunately each time my bg went high due that I was able to get things worked out and correct with the pump to get my bg in range.

I'm not sure what I'm going to do if it happens when I'm alseep, if the alarm goes off then I will have to hope it wakes me, which brings me to the question, why did I get the alert when I was on saline but not on insulin? For that one I simply pressed the button to resume insulin delivery and it did. I was only getting basal dosed then at night as I recall I didn't do any boluses and it did alarm while I was sleeping, at least 2 alarms sometime from 6am to 8am and I did wake up from the 8am alarm I think, sometimes I wake up after an alarm but I don't actually hear it waking me up. I think some of the occlusions alerts are minor situations where the tubing gets kinked because that is what seems to happen with a food bolus I did where the pump only bolused half the amount, I resumed insulin and bolused the rest, so maybe it was a kink from clothing pressing on it or the cannula was slight bent and it resolved on its own. My trainer said that happens pretty often to her, the tubing is kinked bit under her clothes, she gets the alert and adjusts it and it goes away.

One thing my cde said which can resolve cannula occlusion issues is to switch to the deeper cannula which is angled or the metal insets. I tried both of those as well as the regular 6mm I'm using but those ones seemed to cause me some pain, but I may try them again if this happens again.

Hi. I’m back after being away a while. I had to re register, so now I’m not just Splash, but Splash 1 :smiley:

I just got a TSlim and by trial and error, found that I had not turned off one of the alarm features during setup. Three mornings, I was sipping my coffee when YIKES! a “serious sounding alarm” went off. On the third morning, I took the time to read what the pump said instead of just pushing the Resume button.

Turns out TSlim has a feature that alarms, then shuts off delivery if none of the buttons have been pushed for 12 hours. I went into options and under alarms, turned it off!

I could see where this may be a good feature in some limited situations, but it was not something I need.


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Welcome back, @Splash1. I have the number after my TuD name, too. I don’t use the T:Slim pump but many here do. You will find many discussions about T:Slim by using the magnifying glass icon to search. It’s in the upper right hand corner of the screen.

I’ve used this auto-off feature on an Animas Ping pump. Every once in a long while it would stop insulin flow due to no buttons being pushed for 12 hours. I understand the rationale but decided to turn it off, too.

Thanks for the welcome, Terry and also the info. Have a good day.