Air Bubbles?

Hi all! My 5 year old son has been on an Animas PING for exactly one year now. Throughout this first year, we have had problems with keeping air bubbles OUT of the cartridge and tubing. When I change his site, say if I change it on wednesday, by the next site change day on Friday, I find air bubbles in the cartridge, and or tubing even though when I changed it on that said wednesday, there were NO air bubbles anywhere to be found in that cartridge or tubing. Its like they just magically appear! I’ve spoke to our local Animas rep about it and she adviced we tighten the cap connecting the tubing to the cartidge more than what the instructions state, which we have tried and still do, however we are still finding that air somehow still seeps in from somewhere, causing air bubbles in the tubing and/or cartridge!

Anyone have any tips or tricks on what I can do to prevent this from happening? Any advice is greatly appreciated! Thanks so much!

The air bubbles are collecting from the air dissolved in the insulin, just like a carbonated beverage. There is probably no aseptic or sterile method to fix this problem experts would agree with your doing. There was a discussion on another thread about filling the cartridges in advance to look for cartridge failure. This may be the option here also.

Other side of the same coin, if you were drawing up insulin in to a syringe and giving it, the dissolved air is still present and thereby injected would stand to reason. This brings the question to bear, are you seeing any high BGs when there is more air in a cartridge?

Just my feeble pondering.

Yes, it seems that by the middle of the second day the bgs tend to go higher, and the only reason I can think of is because of those air bubbles in the cartridge and tubing. Though, your theory does sound logical, and it is one thing myself and my husband has considered as well. Hm, I wonder if I draw up the insulin into the cartridge about an hour before doing the rest of the site change routine, letting everything settle a little, then go back to it and check for air bubbles and try to get them out before putting the cartridge in the pump, if that would work (I dont mean keep him off the pump for an hour during this time, just start filling the cartridge and let it sit for an hour to settle, before disconnecting him from the pump). Hm, might try this and see if it works out any better.

I dont think its necessarily a cartridge failure (crack/leakage issue) just because weve been battling this same issue with air bubbles since day one on the pump. If it was a cartridge failure, it would have corrected itself out by now, with each new lot and/or box we start.

I’ve found that I get air bubbles more often when filling a cartridge with insulin directly from the refridgerator. Letting the cartridge sit for a bit after filling does really seem to help get rid of them.

I have developed a routine that works for me - it may for you as well. I take my insulin out of the refrigerator a few hours before filling the cartridge – I than fill the cartridge and, after ‘tapping it a few times to get all the excess air out and refill it to the top, I cap it and let it stand for a while. Finally, after I inserted the new set into me and have the pump on rewind, I uncap the cartridge and than refill it again from my insulin bottle – making sure there is a small excess of insulin sticking out of the top. Also, although many will debate me on this, I than take the old cartridge and fill the new tubing with it’s remaining insulin. Although the insulin has been ‘out of the refrig’ for 3 days, I have never seen a difference in its potency (unless I have been in the desert for the last 3 days!) and I have not wasted any excess insulin.

I know this does not address your exact issue, but I suspect you too will find a pragmatic approach that will work for your son, and once you do, it will continue to work. Managing diabetes teaches us all to be pragmatic on a daily basis, things are always changing and we are always changing our habits to adjust and fine tune as we go!

Since we go through a vial of insulin within 2-3 weeks, and humalog can last up to 28 days unrefrigerated after it is opened (according to our CDE and pharmacist) i havent been refridgerating it since long before he was on the pump, so i know its not a refridgerated/non-refrigerated thing as well. I’ll just have to play with different techniques I guess, and see what works. Thanks for the feedback though! Glad (but not lol) to see im not the only one that has experienced this issue!

!, too frequently find air bubbles when I change the cartridge, even though I am very careful to eliminate every trace of a bubble when filling the cartridge. Usually they are tiny champagne type bubbles & I never see bubbles in the tubing so I think they stay in the cartridge. This is one reason I never use up all the insulin in the cartridge, I just waste a few units.

I also had it explained to me that this was air dissolved out of the insulin.

I don’t think it affects things as my BG is frequently better on days 3 & 4 of a cartridge, yes I leave my sites in for 4 days sometimes, but I only take about a total of 20 units of insulin per day.

A couple of things -

  1. I have learned the hard way to always keep my insulin in the refrigerator - you may believe that it has remained refrigerated until it gets to you - but that’s not always a good assumption. It CAN go bad on you way before it should be time. Lots and lots of teeny, tiny bubbles can be indicative of this. But usually, if this is the case, you would get occlusion warnings. So - I would advise keeping it in the frig. It doesn’t take long to “warm up” to room temperature AND I’ve found no evidence that “cold” insulin leads to more bubbles.

  2. I fill a cartridge ahead of time and keep it in the frig til I need it. I then remove it from the frig and let it sit out for 30 minutes or so. I check it for bubbles, tap it if needed, and load it.

  3. By the middle of the second day? Well, that’s me, too. I have just learned that, whether it’s because of my sensitive skin or whatever, I MUST change my site ever 2 days. That’s just what is so - for me. Doesn’t have anything to do with bubbles - that’s just how long my body will support a single site.

Actually Novolog is approved to be in a pump for 6 days so the way you prime is ok as far as the insulin goes (that is if you use Novolog). My problem is when I unattach the tube from the old cartridge air gets in the connector and when I screw it onto the new cartridge I can always see air in the tubing. Is there some way you prevent air (it is “bubbles” of insulin with air in it) from getting into the leur lock connector of the infusion set tubing when changing from your old cartridge to the new one?

If I’m using the same tubing, but changing the cartridge, I leave the needle on the cartridge until I’m ready to use it. Then I take the luer on the tubing and shake it out in the sink to empty the insulin that may be caught and bubble there - then I remove the needle & attach the cleaned out luer.

I change my sets every 48 hours - if I don’t, my numbers start going up. I just had to accept it - my sensitive skin will only support it for that long. The doctor supports that, so I get the supplies I need to do so. I also ask her to write my script for about 10 U more a day than I need, to ensure that even with mishaps, I always have enough insulin on hand.

So when you shake it out it will remove the insulin bubbles but there is no air in the tubing when you attach the old tubing to the new cartridge? I will have to give it a try but everytime I do, so far, I end up with a bubble in my tubing (I reuse tubing because I like 43" but have a bunch of 23") and have to prime out all the insulin to get the bubble out.

If I am reading this right, it sounds like you are changing the cartridges more frequently than the tubing? If so… Only thing that comes to mind for this that I could think of would be (if you can) put some extra insulin in your cartridge so that when you prime it, you can prime out the air bubbles that get caught in the leur lock connector. It may mean priming more insulin through the tube than you usually do, but should be able to flush out those air bubbles that keep getting trapped in the leur lock from switching cartridges!

I’ll try filling the cartridge a little ahead of time and letting it sit to “settle” out any possible air bubbles and see if that works. Tomorrow afternoon is our next site change day for him, so I should be able to know for sure if this technique will work for us in a couple days. Thanks for all the tips and suggestions!!!

Aeration of the insulin caused by injection of air directly into the insulin, or excessive tapping of the cartridge during the cartridge fill are two of the biggest cause of fine champagne bubbles . . . which later congregate into larger bubbles that can lodge in the hub of the cartridge near the tubing. Cold insulin causes this as well, and Novolog is especially prone to challenges with aeration . . . Just that same I use Novolog and do not have problems. Use of room temperature insulin is important (Animas recommends 30 min out of frig).

I rarely if ever have problems with bubbles when using the following techniques: 1) Be certain that the needle and cartridge connections are tight before drawing up insulin; 2) Set the insulin vial on a counter or hard surface with the rubber stopper pointing up. Cycle the cartridge twice and fill it with half the volume of air you intend to draw up as insulin; 3) Inject the air into the upright cartridge into the “air space” above the line of insulin in the vial; 4) Turn the insulin vial and cartridge over so insulin now covers the needle; 4) Pull back and fill the cartridge to the 1cc mark. Then, very slowly push the plunger all the way back so that all the insulin is back in the vial. This allows the “dead air space” in the cartridge hub and needle to fill with insulin; 5) Pull back to the 1 cc mark again very slowly, and push the plunger up a second time if needed . . . until you can see that there is no air in the hub; 6) Thread the tubing through the cartridge cap and connect SECURELY to the cartridge . . . do NOT attach the extra cap that comes in the package unless you need to store it without a needle; 7) “Hand prime” the tubing by gently pushing insulin up 2 to 3 inches up into the tubing. Check to be sure there is not a bubble in the hub where the tubing and cartridge connect. If you see a bubble, gently tap on the hub of the tubing to allow the bubble to line up with the opening of the tubing and gently push the bubble up into the tubing. Be sure there is no air in the connection between the tubing and cartridge; 8) THEN . . . place the cartridge in the pump and prime as usual. Check the tubing to be sure there are no bubbles. If you see bubbles, prime until they are out of the tubing. In this way, I am almost always able to avoid tapping the cartridge . . . which causes aeration of the insulin.

On occasion I have found that an individual set of tubing will not allow me to push the bubble out of the hub into the tubing . . . like the bubble hangs up around the plastic of the tubing because the tubing itself projects into the hub further than usual. If I see this, I start with fresh tubing.

To tell you the truth, I have never gotten a bubble in my tubing - ever. I use the Orbit Micros, which have blue tubing - makes it easier to see any issues.