# Yet another question



## brett (Apr 14, 2013)

Sorry, coming across something all the time lol.  I'm sure I read to change the insulin cartridge every 10 days.  Is that right?  I would estimate that if it was full it  would last maybe 20 days maybe less depending how greedy id been.  If that is correct could I fill l the insulin cartridge half way only and keep the rest of the vial in the refrigerator to be used next time.  Using accu chek combo


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## everydayupsanddowns (Apr 14, 2013)

I only ever half fill my cartridges as Medtronic ones are only supposed to be used for 3 days. The 'in use' vial should stay out of the fridge so that it is at room temp (helps prevent bubbles forming in the cart). Vials can stay out of the fridge for 28 days by which time you'll prob have used all the insulin.

Medtronic also say that once the cart is filled it should be used straight away - so not prefilled and stored for use later. Not sure about Roche guidelines tho.


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## m1dnc (Apr 14, 2013)

I was told to change it every 6 days, so I fill it with enough to last 6 days plus a bit for over-indulgence. That way you change the full infusion set with tubing at the same time as the reservoir change, with just a cannula change at three days. A nice simple routine. Put another way, I change the reservoir and full infusion set when the reservoir is empty, and the cannula when it is half empty. At my age, simple routines are highly desirable!


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## brett (Apr 14, 2013)

Yes, was told to keep in use vials out of fridge (forgot that).  Was told ten days use though  but will fill enough for 6 days plus a bit extra, so that I'm not wasting more than I have too.


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## Redkite (Apr 14, 2013)

brett said:


> Sorry, coming across something all the time lol.  I'm sure I read to change the insulin cartridge every 10 days.  Is that right?  I would estimate that if it was full it  would last maybe 20 days maybe less depending how greedy id been.  If that is correct could I fill l the insulin cartridge half way only and keep the rest of the vial in the refrigerator to be used next time.  Using accu chek combo


Hi Brett,

We change the whole set (reservoir, tubing and cannula) every 2 days, only filling the cartridge to 1ml which is more than enough when he's on no more than 30u total daily dose.  The reasoning being that although insulin can be kept at room temp for 28 days, the insulin in the pump reservoir and tubing is right up against his skin and therefore closer to body temp than room temp so deteriorates faster.  If we go into a third day we sometimes get bubbles forming in the cartridge, which is a sure sign the insulin has warmed up.


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## HOBIE (Apr 14, 2013)

Hi Redkite, Bubbles can not form ?  They must be in when filling.


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## Redkite (Apr 14, 2013)

HOBIE said:


> Hi Redkite, Bubbles can not form ?  They must be in when filling.


Hi Hobie, just reporting what we see . I am very careful to eliminate all bubbles on filling, though can't guarantee 100% bubble free, def 99%! but by day 3 some start to appear.  We were told by the Medtronic Rep when we were trained a few years back that the reason for keeping the vial out of the fridge is that using cold insulin in the cartridge leads to bubbles forming when it warms up to room temp, because there is nowhere for the dissolved air to escape when it begins to evaporate.


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## m1dnc (Apr 14, 2013)

HOBIE said:


> Hi Redkite, Bubbles can not form ?  They must be in when filling.



That's not right I'm afraid. The solubility of a gas in a liquid is inversely proportional to temperature (Henry's Law). So if you fill your reservoir at, say, room temperature, bubbles will form as the gas comes out of solution at the slightly higher temperature of the reservoir in the pump next to your body.

This was what was noted by Redkite, and which most of us with pumps will probably have noticed. I certainly have.


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## HOBIE (Apr 14, 2013)

Is it some new insulin with gas in ???  It must be majic water into wine


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## m1dnc (Apr 14, 2013)

No need for magic! The original insulin will have some air dissolved in it which will come out as gas bubbles when it warms up.


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## m1dnc (Apr 14, 2013)

m1dnc said:


> No need for magic! The original insulin will have some air dissolved in it which will come out as gas bubbles when it warms up.



Think of a saucepan of water for boiling an egg. As you heat it up before the water itself boils, you get lots of little bubbles. This is the air that had been dissolved in the water coming out of solution. It's the same for the insulin in the reservoir warming up against your body.


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## Redkite (Apr 14, 2013)

HOBIE said:


> Is it some new insulin with gas in ???  It must be majic water into wine


Lol, if only!  Actually, when I've been decanting things out of the sharps bin I've come across used cartridges which look like they contain champagne, they're that bubbly 

m1dnc, you're obviously a scientist - it's a very long time since I did any physics, in fact the only law I can remember is s0d's law!!


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## everydayupsanddowns (Apr 14, 2013)

No matter how much I flicked and jiggled reservoirs in the early months I would always get bubbles appearing (that hadn't been there before) after 12 hours or so. I now tend to fill with a slight vacuum (not filling with all the air in the reservoir for the amount of insulin) - seems to help me a little.


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## m1dnc (Apr 14, 2013)

One trick I've tried a few times, is to warm up the insulin phial in a pocket next to your skin for 10/15 mins before filling the reservoir. The trouble is that it tends to shake up the insulin at the same time. What The Lord giveth, The Lord taketh away!


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## HOBIE (Apr 14, 2013)

There SHOULD be BIG warning signs on where you get YOUR insulin from.  Warm a few degrees & covert to AIR ?????????????.  People going to a hot country on holiday be very careful of hot air.  After 5yrs of pumping i have Never had air in a cannula.


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## Hanmillmum (Apr 14, 2013)

HOBIE said:


> There SHOULD be BIG warning signs on where you get YOUR insulin from.  Warm a few degrees & covert to AIR ?????????????.  People going to a hot country on holiday be very careful of hot air.  After 5yrs of pumping i have Never had air in a cannula.



So what is your technique? Is it how you draw up, or how you carry it ? We still get the odd bubble here and there when there are none in the reservoir to start with ! V Frustrating!!


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## everydayupsanddowns (Apr 14, 2013)

Hanmillmum said:


> So what is your technique? Is it how you draw up, or how you carry it ? We still get the odd bubble here and there when there are none in the reservoir to start with ! V Frustrating!!



I still find those bubbles very frustrating. They are NOT there when I fill the reservoir, but later on I've caught a big fat bubble wandering up the tubing more than once!


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## Hanmillmum (Apr 14, 2013)

I really do think it has something to do with temperature. DD carries hers close to her by it being in her vest against her abdomen, quite a warm spot. Noticed too on hols in the heat there were a few more bubbles than normal.

I find I have to do a check as part of the routine of bolusing, there is probably one incident each change of cannula/new reservoir.


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## HOBIE (Apr 14, 2013)

I use a medtronic pump. You fill canula & get air out same as syringe. Connect cannula to tubeing & hold vertical with pump & cannula on bottom. Needle etc on top, set pump away to fill tube holding needle in air & wait for drips coming out.        No air.


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## Redkite (Apr 14, 2013)

HOBIE said:


> I use a medtronic pump. You fill canula & get air out same as syringe. Connect cannula to tubeing & hold vertical with pump & cannula on bottom. Needle etc on top, set pump away to fill tube holding needle in air & wait for drips coming out.        No air.


Perhaps there's an element of luck!  My son has a Medtronic Veo too - I'm pretty good at getting a bubble free reservoir to start off with (using the technique of leaving a small vacuum in the vial), but as I said by day 3 there will be a few bubbles in there.  We keep an eye on the tubing when bolusing to make sure no bubbles are moving along, and haven't had any problems.  He wears his pump in a pouch next to his tummy under 3 layers of clothing, so a bit warmer than if clipped on a belt for example.

Hobie, if you're not troubled by bubbles then great, but for those who are, changing the reservoir more frequently is a good tip.  The original poster wanted to know if you could keep the same reservoir for 10 days, which personally speaking we certainly couldn't.


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## Hanmillmum (Apr 15, 2013)

HOBIE said:


> I use a medtronic pump. You fill canula & get air out same as syringe. Connect cannula to tubeing & hold vertical with pump & cannula on bottom. Needle etc on top, set pump away to fill tube holding needle in air & wait for drips coming out.        No air.



Yep, can do all that fine, have been pumping a while and feel technique is fine thanks, it's what occurs after -  maybe on day 2/3, close to being due a change ( just as Redkite finds)


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## Pumper_Sue (Apr 15, 2013)

I have been told to use the cartridge for 6 days only. I used to go 14 days when I self funded.
Only time I have had bubbles is user error in filling the cartridge. (x2 in 5 years)
Insulin stays in the fridge until 20 mins before a refill is needed. Then removed to warm up to room temp.


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## everydayupsanddowns (Apr 15, 2013)

I do keep the pump under the duvet clipped to waistband - the stuff about temp differences is very interesting and could explain a lot!

Hobie and Sue - hats off to you both for your 'no bubble' record, but I can say with 100% certainty that some of the bubbles I have seen at the end of 2.5 days when I tend to change were not there when the cart was filled.


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## sacol4940 (Apr 15, 2013)

I often get teeny bubbles appear in the cartridge, but so far they haven't caused any issues

They definitely weren't there when I filled it so presume its from the change in temperature


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## HOBIE (Apr 15, 2013)

Bubbles can not appear from thin air (majic).  A temp change cannot do it. People on injections would be same, you cannot produse air without a chemical/gas reaction. Does it make any differance what type of insulin ??


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## LeeLee (Apr 15, 2013)

Half fill a glass of water and leave it for a day on a warm window sill.  Bubbles.


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## everydayupsanddowns (Apr 15, 2013)

As a little experiment... I changed my set/reservoir at lunchtime (so it hasn't been under the duvet yet). I just tapped and knocked it, and have taken a pic. I will post a compare-and-contrast tomorrow if any bubbles appear overnight!


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## HOBIE (Apr 15, 2013)

It is in a vacume ??? Or should be.  Think about a syringe. Long acting insulin in it, lasts for weeks ???


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## Redkite (Apr 16, 2013)

everydayupsanddowns said:


> As a little experiment... I changed my set/reservoir at lunchtime (so it hasn't been under the duvet yet). I just tapped and knocked it, and have taken a pic. I will post a compare-and-contrast tomorrow if any bubbles appear overnight!


That will be interesting to see.  Why not keep the cartridge for a few days after you next change it and take a photo after a week?  Bet there will be lots of little bubbles.....


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## Redkite (Apr 16, 2013)

HOBIE said:


> It is in a vacume ??? Or should be.  Think about a syringe. Long acting insulin in it, lasts for weeks ???


The air is already present dissolved in the insulin, just as it would be in any other liquid, and as one of the previous posters said, it begins to evaporate out as the insulin warms up.  Not magic, just science!

Hobie, if you prefer to think those of us who get bubbles are just incompetent at reservoir-filling, we'll just have to agree to disagree lol!  What's important is that everyone who pumps has a strategy for preventing bubbles from mucking up their insulin delivery - that's all that matters at the end of the day


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## Pumper_Sue (Apr 16, 2013)

Some people find the bubble solution is to fill the cartridge tap out bubbles and stand the cartridge for 30 mins then have another look and knock out any further bubbles.
The slower you fill the cartridge the less likely you are to have bubbles, also make sure you have all connections tight enough (without breaking connection) so no air gets in.

If you think things out in a logical way if being to warm causes the problem then no one in a hot country would have a pump.


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## everydayupsanddowns (Apr 16, 2013)

Sue and Hobie - can I just gently point out at this point that you are trying to convince me that something I can see happening _doesn't_ happen. As I say - I am pleased for you both that you don't get bubbles forming in your cartridge, but you telling me that they can't appear and must have been there all along just does not match with repeated (and repeatable) experience of 'no bubbles' at fill followed by 'bubbles' some days later.

As to keeping insulin in the fridge in between changes, I was specifically advised by pump DSN to keep the 'in use' insulin at room temperature because it helped *prevent bubbles* forming.

This article (the intro of which closely matches both sides of this conversation funnily enough) makes many suggestions on how to attempt to avoid bubbles if people find that they are a concern for them.

http://www.insulin-pumpers.org.uk/airbubbles/BubbleSuggestions.pdf


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## Pumper_Sue (Apr 16, 2013)

everydayupsanddowns said:


> Sue and Hobie - can I just gently point out at this point that you are trying to convince me that something I can see happening _doesn't_ happen. As I say - I am pleased for you both that you don't get bubbles forming in your cartridge, but you telling me that they can't appear and must have been there all along just does not match with repeated (and repeatable) experience of 'no bubbles' at fill followed by 'bubbles' some days later.
> 
> As to keeping insulin in the fridge in between changes, I was specifically advised by pump DSN to keep the 'in use' insulin at room temperature because it helped *prevent bubbles* forming.
> 
> ...



With respect Mike, I am not trying to convince you of anything.
You have bubbles, I do not. So there must be a diff somewhere. 

I have always kept my insulin in the fridge it stops it breaking down over the month it's kept out of the fridge thus losing it's potency


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## Redkite (Apr 16, 2013)

Pumper_Sue said:


> Some people find the bubble solution is to fill the cartridge tap out bubbles and stand the cartridge for 30 mins then have another look and knock out any further bubbles.
> The slower you fill the cartridge the less likely you are to have bubbles, also make sure you have all connections tight enough (without breaking connection) so no air gets in.
> 
> If you think things out in a logical way if being to warm causes the problem then no one in a hot country would have a pump.


The scientific logic is the same in hot countries - you just start from a warmer temperature in the first place, and any further warming leads to air bubbles evaporating out.  Excessive heat will obviously cause the insulin to deteriorate, so we use a Frio pump pouch when travelling in hot climates.


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## everydayupsanddowns (Apr 16, 2013)

Pumper_Sue said:


> With respect Mike, I am not trying to convince you of anything.
> You have bubbles, I do not. So there must be a diff somewhere.



Indeed there must! I get more bubbles sometimes, and fewer bubbles at others, so I suspect there must be a number of factors at play (as with everything D eh!). You'll forgive me if I misread some of your earlier references to 'user error' being the only reason you'd ever seen a bubble in years of pumping to be a suggestion that any bubbles I got were my own silly fault 



Pumper_Sue said:


> I have always kept my insulin in the fridge it stops it breaking down over the month it's kept out of the fridge thus losing it's potency



Not sure about animal insulins, but analogues are rated to be fine at 'room temperature' (with all the variation that involves) for 28 days so I'm not so worried on that score unless we are somewhere hot/holiday etc.

Following the temperature tip on this thread though, I may well see if I can get a filled cartridge up closer to 'operating' temp (in/around body heat) for a short while before trying to flick out any last bubbles prior to connecting tubing etc.


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## Pumper_Sue (Apr 16, 2013)

everydayupsanddowns said:


> Indeed there must! I get more bubbles sometimes, and fewer bubbles at others, so I suspect there must be a number of factors at play (as with everything D eh!). You'll forgive me if I misread some of your earlier references to 'user error' being the only reason you'd ever seen a bubble in years of pumping to be a suggestion that any bubbles I got were my own silly fault
> Nope I wasn't suggesting you or anyone else's were due to own silly! fault. I do know though the 2 times I have ended up with bubbles was due to me not getting rid of the bubbles completely in the first place.
> 
> 
> ...



Another logical thought ( I need a rest) if bubbles were a major problem with everyone then the pumps would not be a viable medical device, esp for small children due to DKA.


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## everydayupsanddowns (Apr 16, 2013)

Pumper_Sue said:


> Another logical thought ( I need a rest) if bubbles were a major problem with everyone then the pumps would not be a viable medical device, esp for small children due to DKA.



Sue please!!

I never said they were a 'major problem' for me. They are an occasional nuisance. More often than not the bubbles stay benignly in the reservoir. A handful of times I have spotted a 3-4mm bubble making its way up the tubing and dealt with it. I think perhaps twice in nearly 2 years I've had a minor high (low teens) and thought 'I wonder if that was a bubble?' because I couldn't think of another more likely reason.

Look... I've just fished 3 old reservoirs out of my sharps bin. You can see that the top 2 have a couple of fairly fat bubbles stuck near the 'o' rings, while the bottom one has almost nothing. I think it is fairly safe to say that I would need to be VERY inattentive while filling not to have spotted these biggies if they had been there when I filled the reservoir!







Let's just accept that we have a different experience of this.   

EDIT: Just read your 'inline' notes. So sorry to have peed you off. That certainly was not my intention, I just genuinely didn't know if animal insulin was more heat sensitive. Ironically in 22 years of being D the only time I have ever dumped insulin it was Lantus that was *in* the fridge (which had developed a fault and had developed some warm spots).

I'm going to back out of this thread now. Hope you can forgive any annoyance I may have caused you.


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## Redkite (Apr 16, 2013)

Great photo everydayupsanddowns, that's exactly what we see too!

I agree there's no point bickering about it.  So long as all pumpers are aware that bubbles are to be avoided, it doesn't matter whose technique we use.  There are lots of "right" approaches 

Kids don't go into DKA from bubbles because parents are taught to keep vial out of fridge and regularly inspect the cartridge and tubing during use.  And most importantly of all, to test BG frequently and respond appropriately to highs.


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## heasandford (Dec 9, 2013)

I know this is a long time after this thread started (I searched 'bubbles' and looked for replies in the Pumping section) but these answers have been enormously helpful, (even if there was a bit of dispute) 
It's what makes this forum so incredibly useful, I am grateful for peer replies that I feel are trustworthy. Pumping for 2 weeks now, not brilliant, but getting somewhere I think!


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## ch1ps (Dec 9, 2013)

I've had a problem with bubbles in my cartridge on filling.  This seems to have gotten better with practice 

I am on a medtronic and have noticed bubbles that were not there on filling are there on removal.

Just adding my tuppence worth


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## trophywench (Dec 9, 2013)

I just change my cartridge when it's empty - around 10 days.

Insulin stays in the fridge until c half an hour before filling the cartridge, goes straight back in fridge after.  The only advice re fridging I ever had was in 1972 when of course I was on piggy insulin, but never been told any different so never done any different.  After 40+ years doing this I'd have to find some place else to put it, errr, where?

I have only had air in the tubing twice so far since I got the pump in May 2011 although yep, there are sometimes a few in the vial; if there's a lot I probably change the vial a bit sooner.  (say a day sooner, that's about 20u)

If there were a shedload when I was say halfway down the res I'd just disconnect at the reservoir end and prime em out again and reattach, prime and carry on again till the res was empty.

Pump is usually on my waistband in a skin or it may be on a lanyard round my nice next to me (the lanyard attaches to one of those 'suedette' pouches) but the only time I take care of it better is if it's freezing cold when I try and bury it nearer my skin with a jumper/cardy over it to keep it a bit warmer, but I don't worry if it's 30+ either - just put it by the side of me so it gets shade from my body when I lie out in the sun to bake.

Not noticed any practical difference TBH, although in very hot weather I do actually use up to about a third less insulin so the res lasts even longer, and the pump usually frightens the life out of me when it eventually alarms to warn me I only have 20u left - that's a whole day mostly! so defo no need to panic.

Each to their own, as they find .......


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