Air Bubbles in Tubing

I rarely have problems with air bubbles but this last week, I have had a ton of them. One day last week, I used about 70 units just to keep priming the bubbles out. I finally decided to change the tubing and that seemed to help. Last night, I started getting them again so changed the tube out (although it was a brand new site so that should not have been a problem). Today, I have had to prime it a couple times because of bubbles. My BS is running high so I am guessing it is the stupid bubbles causing the problem. Any ideas what can cause this?

i haven’t experienced this myself but my thoughts are: after tube, reservoir and site change, the only thing left in that part of the pump is the cap. could it be the cap isn’t tightening right or something?

Hey Kelly,

Try making sure that the insulin is room temperature before filling the reservoir - if I fill it directly out of the fridge it tends to get a lot of bubbles. Also, make sure that you inject a cartridge's volume of air into the vial before you try to pull insulin back out - it creates pressure inside the vial which makes it easier to fill without bubbles. Without doing that, there's negative pressure (vacuum) inside the vial, which tends to make more bubbles. Lastly, try filling the cartridge a little more slowly - that often helps me too.

Just a few tips. :) Good luck!


Thanks Marti. I was just starting to wonder about the cap. It looks OK but I know they said to replace it every 6 months and I am at the 6 month point with my pump so maybe that is it. I guess I will have to order one.

Thanks Chris. I usually do take the insulin right out of the fridge so I will try letting it get to room temp the next time I change my cartridge (which I will have to do soon with all the insulin I have wasted!). I do put the same volume of air in the cartridge. I will also go slower when I fill it up.

On the rare occasion that I have bubbles in the line, I will change, vial (cartridge) and insulin. It may seem like overkill, but it eliminates the most likely cause of bubbles all at once.

A couple of other hints: I warm the bottle of insulin plucked from the fridge by holding it in my closed fist. It generally takes only a few minutes to get relatively "warm", and I think it's quicker to warm it this way than to just let the bottle sit on the counter.

My technique for eliminating 99 percent of the air at "fill time" when loading a new vial is to do the following: (some of this has already been mentioned).

1. Warm the bottle.

2. Hold the bottle normally (not inverted) and push a full vial's worth of air into the bottle.

3. Invert the bottle and slowly draw up the amount of insulin you want. (I hold the bottle in one hand, and grasp the base of the needle with my thumb and "pointer finger" and pull the plunger with my other hand till the vial is full. I try and NOT grasp any part of the vial with my fingers while filling, so that it isn't deformed...and no extra pressure put on the inner 'O' rings which could allow air to enter.

I initially only draw up 25 50 units into the vial, then slowly push them back out into the (still inverted) bottle of insulin. You will be AMAZED at the amount of air that usually comes out.

4. Let the vial sit on the counter for at least 5 minutes (while you are prepping your new site and attaching your new infusion set to your skin).

5 Once your all ready to go, pick up the vial , tap it a few times at the top, and put the blue piece back in the bottom, and insert vial and (still connected) needle back into the inverted bottle of insulin. Push some insulin out, and look for air bubbles. Draw up what you pushed out, and you can then fill your line.

I've done the steps above for about 2 years, and have only had one occurrence of a MASSIVE air bubble.


A couple things I might add to the previous comments: 1) Injecting air into the insulin vial is an important step to even out pressure . . . but you can also get too much air in the vial and cause the same problem. I generally put a little over half the volume of air I plan to use into the upright vial of insulin and then turn the vial over to cover the needle before filling. If the rubber septum of the insulin vial is bulging, or the plunger pushes itself out, you have too much air in the vial; if the rubber septum is sucked in, and it is difficult to pull the plunger back, you have too little air in the vial. 2) Make sure that the needle is securely fastened to the cartridge before filling, and that the tubing is securely fastened to the cartridge after filling . . . to prevent sucking ir into the cartridge when there is change in pressure.

1 Like

Thanks Joe! I do put the air into the insulin bottle while it is standing up and then flip it over. I don’t do the other things that you suggest though so I will try doing that next cartridge change. I did change out the cartridge again last night and haven’t had any bubbles with this one.

Thanks Leilani! I usually put the full amount of air so I will start using half. I do seem to have problems pulling the plunger back though.

It is recommended that you “cycle” the cartridge by pulling the plunger back and forth 2 times prior to filling with insulin to distribute the lubricant . . . and when you are pulling the plunger back, be sure to hold the blue handle below the little tabs that clip it into the cartridge so it does not come off. If the cartridge feels stiff when you cycle, you may want to call the Customer Service Dept . . . as that is not normal. And, be sure that your cartridges are not expired or stored in extreme temperatures as it dries out the lubricant and makes it stiff. . . and can lead to occlusion and loss of prime alarms. Reused cartridges can cause the same.

I do the cycling part. I will have to check the date on the cartridges. They should not be expired since the supply company just shipped them in Oct but I guess I should pay more attention to that stuff! I keep them in the closet in the upstairs hallway and it is about 65 degrees up there so the temp should not be a problem. I will also pay more attention to how I am holding it! Thanks again for your help!

Kelly, Wow I can't believe it's been 6 months already. Time flies so fast.

Anyway I wouldn't be surprised if it's the fridge cold insulin that's a major culprit here. When I've forgotten to pull a bottle out ahead of time I tend to get air bubbles as the insulin comes up to room temp. I haven't had any problems keeping my vials in use at room temp even in the summer. It doesn't usually get hot in W Washington though.

If you really like keeping your insulin in the fridge try prefilling the cartridge and letting it come to room temp before attaching it to your pump/infusion set. You'd still have to possibly prime out some air bubbles but it might be easier if done before you add the cap, pump and vents into the mix.

Good luck. Hope you solve the bubble problem.

Hi Kelly -

Don't know if this applies or if it will help, but the only time this type of thing has happened to me is when my insulin went bad - way before it should have - AND - way before it "showed"


Bubble Update

Diana & Cheri, I thought I answered your replies to me and I apparently did not! I apologize! Cheri, I thought it actually might be the insulin. I did end up having some bad insulin & when I replaced it, the problem went away.

It started again last weekend so I have been working with Animas. They had me try a couple things and so far, nothing has worked. One of the things she wanted me to do was take the blue plunger off and leave the cartridge sitting with the needle straight up for about half an hour before putting it in the pump. I did manage to keep it on 12 hours last night before the bubbles started. She was going to send me some cartridges & infusion sets to try. She was sending them so they would be here tomorrow morning. By chance, my supply order showed up – I wasn’t expecting that to come until next week. I have the insulin sitting out to warm up. If this doesn’t work, then it has to be the pump. I am hoping it was just some bad cartridges!

Hi Kelly…

I >hate< to say this, but the SAME THING happened to another user here on TuDiabetes about a year ago. She was plagued with tiny bubbles in her cartridges very often. She ended up having to get another pump from Animas. The “good news” is that Animas didn’t give her any hassle about exchanging her pump for another.


Thanks Joe. I actually found that post when I searched for bubbles in the Animas group. I bookmarked it just in case! I already did hear from someone at Animas that it could not be the pump. I remembered reading that so I have if I need it. I am really hoping it was just some bad cartridges! I guess by tomorrow I will know for sure.

Just seeing your discussion now - and am hoping your bubbles problems get sorted out. I’ve only been pumping a few years now, and so far, no bubbles in tubing. I’ve heard about not filling up cartridge with insulin directly from fridge, the only time I use room temp insulin is when I’m on the road/sailing - as I don’t have use of fridge. Anyway, when at home, I take the vial out of fridge, and do the"usual" thing of filling up. Ouch on priming with 70 units of insulin. I think if it keeps on happening tho’, even with whatever Animas sends to you, the next step … new pump.

Anna, the new cartridges didn’t help. Like the one the night before, it did good for about 12 hours then started up again. I pulled it off this morning. While I was in the shower, the Animas clinical manager for the Pittsburgh area called me. I had worked with her when I first got the pump and she sent me some sample infusion sets. They changed their areas around and I am no longer in her area, but she heard I was going to be at a doctor’s appointment in Pittsburgh today. She met me at my doctor’s office. She agreed that I wasn’t doing anything wrong other than I should only cycle it 2 times. She said she did not think that would cause a problem. She brought saline for me to use but I wanted to go ahead & put insulin in. I set a temp basal of -90% to wait until the Levemir worked its way out of my system. Today was a non-diabetic lunch so I wasn’t worried about going low! If it is still running OK by the time I go to bed, I am going to set my alarm a few times to get up and check on it.

I just wanted to let everyone know that Animas called me after I posted yesterday that they are going to replace the pump. She wasn’t convinced that it was a pump issue but they are going to replace it. I don’t know how it can’t be a pump issue. I used different infusion sets and cartridges from 3 different sources. I replaced the cartridge cap. I followed all their instructions on how they wanted the cartridge filled and someone from Animas even watched me doing it. The person that I met with yesterday told me that if they replace the pump, they put the pump thru tests when they get it back & it takes about 10 weeks for them to do that. I don’t know if they will share those results with me or not.

About an hour after Animas called, I started getting huge gaps of air in the tubing again so I just pulled the pump off.

Although I do keep a printout of my settings, I do think I made some minor adjustments to my basal rates after I printed those out so I need to do that this morning before the new pump shows up.

I’m glad Animas is sending you another pump! Please let us know if the replacement pump solves your problem…