Avoiding Air Bubbles In Insulin Pens?

handicapable

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I've been storing both my NovoRapid & Lantus Solostar open injection pens in the coolest place I could find in my house (in a drawer in the kitchen, inside a Tupperware box), I have been removing the needles straight away after use and putting the pen lids back on yet they are still getting air bubbles (the unused ones are stored in the fridge of course).

Is there something I'm doing wrong here or do I need a special cooler box due to the weather because I've read that once they have air bubbles inside the dose can be quite inaccurate?
 

Antje77

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My pens always have air bubbles. I just inject with the needle end a little (or a lot, depending on injection site) lower than the push-button end so no chance the air will compromise an injection.
Opened pens are fine for a month as long as they stay under 30 degrees Celsius. Nothing wrong with putting them in the fridge either, if it's very hot at your place, only thing with that is that it might sting a bit when straight from the fridge.
 

Jaylee

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Hi @handicapable ,

Air bubbles can't always be avoided.

First thing i would ask. Do you point the needle skyward, give the pen a little flick or tap to loosen any bubbles to the top & perform an "airshot?" Expelling air, thus priming the needle for injecting...

The hot weather we are having recently could also be causing a little expansion creating larger or more noticeable air bubbles..?
Someone please shoot me if the science is wrong? I'm working off this. (Yep another car analogy!) ;) https://info.kaltire.com/summer-tire-pressure-mind-psi/
 

Antje77

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give the pen a little flick or tap to loosen any bubbles to the top & perform an "airshot?" Expelling air,
I can shoot upward as much as I want, bubble is still there. My guess is that the needles are too tiny to let it properly out. Of course we've all seen tv-shows where a syringe is tapped and an airshot performed before injecting, and I do see the wisdom of that with injecting intraveneus. But there must be a reason why the very long winded leaflet that comes with the insulin pens doesn't speak about getting air out. The only thing that's said is to squirt 1 or 2 units (depending on brand) before injecting. As far as I know that's to check if the needle works and to fill the needle itself with insulin, which makes sense with very small doses.
Neither did my nurse instruct me to try to get air bubbles out. Anyone elses did?
 

Scott-C

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@handicapable , I think you're going through a stage which many newly dx-d go through. Not criticising you at all for that - we all do, I did - it's perfectly understandable in the early days.

When I was first dx'd, I was totally paranoid about the refridgeration thing. I'd be eating out, and asking waiters to pop my insulin in the fridge.

Time went by and I learned more about it - insulin is fine out of a fridge for extended periods, air bubbles aren't much of a problem either provided you do an airshot to get rid of the bigger ones.

One of the most important things to learn in these early days for you is that "accuracy" in a T1 context doesn't actually exist.

You'll be told that it's 1 to 10 or whatever, and you might expect, naively, that that ratio will work, avoid air bubbles etc. etc.but the savage truth is that as soon as you start injecting insulin and eating food, they will be subject to lots of biological processes which we can't see, measure or control.

That means that ratios, the sort of certainty which newly dx-d are seeking, will often not pan out that well.

The trick, though, is to accept that this is an inherently unpredictable condition, and it needs some input on the fly.

Libre and cgm helps shedloads with that - I made a careful calculation for lunch, then a while later it looks like I got it wrong, so I'll fire in another 2u or 5g to nudge it back into line before it goes out of range.

Not a failure at all, just me responding in real time to a constantly moving unpredictable situation.

Many of the dsns and docs you will meet are not yet familiar with this stuff. Stephen Ponder's book Sugar Surfing is a good lead into it, also William Lee Duboui's Beyond Fingersticks.
 
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Jaylee

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Hi @Antje77 ,

I'm an "old school" injector from "back in the day.." When pulling up from a vial with a syringe, I used to replace the insulin drawn up with the same units of air. This was to avoid the rubber membrane on the lid collapsing in under the vacuum created by the missing contents? Drew out a little extra & primed the rather large needle..

I guess old habits die hard with these fangled new pens... ;) :D
 
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LooperCat

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The needle sticks into the cartridge/reservoir a fair way, so when you hold it upright, the bubbles are above the entrance to the needle. So they won’t come out, basically.
 
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Antje77

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The needle sticks into the cartridge/reservoir a fair way, so when you hold it upright, the bubbles are above the entrance to the needle. So they won’t come out, basically.
Can't believe I didn't figure that one out myself!
 

LooperCat

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Can't believe I didn't figure that one out myself!
We’re all so conditioned to seeing murderers in films injecting air into helpless victims to kill them, I suspect! But a subcutaneous bubble wouldn’t do any damage, it’s only if it was into the heart or brain that it would cause an issue. And my needles ain’t that long!
 

Antje77

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We’re all so conditioned to seeing murderers in films injecting air into helpless victims to kill them, I suspect! But a subcutaneous bubble wouldn’t do any damage, it’s only if it was into the heart or brain that it would cause an issue. And my needles ain’t that long!
I know , and I haven't been concerned about bubbles, but I have spent some time trying to figure out why they wouldn't leave the pen. Hence my feeling a bit, err, :wacky:
 

Jaylee

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The needle sticks into the cartridge/reservoir a fair way, so when you hold it upright, the bubbles are above the entrance to the needle. So they won’t come out, basically.

I can't argue with that Mel. However, if you unscrew the needle to the point it sits before biting the thread? Most the air can be expelled from the cartridge..
 
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Antje77

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I can't argue with that Mel. However, if you unscrew the needle to the point it sits before biting the thread? Most the air can be expelled from the cartridge..
But why would you?
 

Jaylee

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But why would you?

Interestingly for me. Any air trapped may cushion the dosage dialed to administer by the ram pushing the bung whilst injecting? like a shock absorber on a car. The trapped air acts as a "dampener" to the push of the ram on the insulin dispensed..
Just skeptical about what is actually delivered (Dose wise.) with too much air in the cartridge?? ;)

How many times have you read a topic where a little insulin is still dripping from the needle, or left on the skin surface when withdrawn..
 

Antje77

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Interestingly for me. Any air trapped may cushion the dosage dialed to administer by the ram pushing the bung whilst injecting? like a shock absorber on a car. The trapped air acts as a "dampener" to the push of the ram on the insulin dispensed..
Just skeptical about what is actually delivered (Dose wise.) with too much air in the cartridge?? ;)

How many times have you read a topic where a little insulin is still dripping from the needle, or left on the skin surface when withdrawn..
I follow your thinking, but I don't think it works that way. I think the air stays in the pen throughout it's life, and thus affects dosing the same with every dose, should it even have an effect.
As the correct dose is based on previous doses things should work out just fine, air and all.
But I think @Mel dCP had the best thinking regarding air in pens so I'd love to hear her thoughts about this.

Another thought : these are all technical-philosophical concerns, and not relevant to someone worried about insulin use, like topic starter.
So to be clear, @handicapable , your insulin is fine to use, air bubbles and all!
 

Jaylee

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I follow your thinking, but I don't think it works that way. I think the air stays in the pen throughout it's life, and thus affects dosing the same with every dose, should it even have an effect.
As the correct dose is based on previous doses things should work out just fine, air and all.
But I think @Mel dCP had the best thinking regarding air in pens so I'd love to hear her thoughts about this.

Another thought : these are all technical-philosophical concerns, and not relevant to someone worried about insulin use, like topic starter.
So to be clear, @handicapable , your insulin is fine to use, air bubbles and all!

Just keep the pen perpendicular when injecting. all good!
 

kitedoc

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Just to provide a perspective from an 'insulin pumper' ( ? good name for a T shirt?), I draw up insulin from a pen cartridge (one in a pen device) into a pump cartridge/reservoir/syringe.. Even drawing up from the pen cartridge full there is some air (dead space) in the pump syringe which swirls about. I think that the drawing back on the pump syringe plunger creates a lot of suction, as the rubber plunger on the pen cartridge has to move/slide/be drawn down the glass tube. I think (without scientific certainty) the suction pressure draws more air out of the insulin itself.
With myAnimas pump syringe even held upright with a traditional needle which does not protrude into the syringe, it difficult to rid air bubbles from it. Rapid tapping just seems to break up the air bubbles, makes it more difficult to get every single one out.
In the 'good, old days' when mixing short and long-acting insulin in the same syringe for injection, too rapid a shaking led to air bubbles forming in the mix. We were taught to roll the syringe horizontally to and fro as a gentler form of mixing

But there are two 'saving graces': 1) In the pump cartridge changeover the tubing of the needle insert needs to be filled, so the pump pushes insulin and hopefully any air bubbles from the pump cartridge out. 2) an air bubble in the tubing sets out an obstruction alarm - bit of a pain as you have to flush the tubing out.
 

LooperCat

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As I understand it, the dribbles of insulin we see after a shot are to do with the lower pressure in the air compared to inside the body. As long as the pen is primed properly with an air shot, which fills the needle with insulin, it will deliver the correct dose. We did have a thread about it a while ago, and some very clever engineering types explained it properly. Complete with formulae ;)
 

MelissaC

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I've been storing both my NovoRapid & Lantus Solostar open injection pens in the coolest place I could find in my house (in a drawer in the kitchen, inside a Tupperware box), I have been removing the needles straight away after use and putting the pen lids back on yet they are still getting air bubbles (the unused ones are stored in the fridge of course).

Is there something I'm doing wrong here or do I need a special cooler box due to the weather because I've read that once they have air bubbles inside the dose can be quite inaccurate?

When I was diagnosed, I was told to roll the insulin pen between both hands to get rid of any air bubbles. It works most of the time, but to be honest I don't always check for bubbles these days! I suppose that's what happens when you've been diabetic for 11 years...

:)
 

Struma

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Out of interest, from a safety point of view, (not a dosing point of view,) you need 15-20ml of air intravenously for it to be fatal