# Bubbles in reservoirs



## Matt Cycle (Jun 18, 2019)

I use the 640G in which you have to fill the reservoir from a vial - syringe style.  Set changes are every 3 days but occasionally I've noticed when removing the reservoir there are a few small bubbles in it.  I usually have anything between 20-45u left and haven't noticed a problem caused by these bubbles.  Where are they coming from?  I spend ages tapping the reservoir to get rid of all bubbles but they seem to magically appear and I only see this when removing the reservoir.

I've had high readings over the last 2.5 days including on the Cycle for Cities bike ride yesterday which I put down to stress.  Stress would have affected it but high readings again today after no reduced TBR overnight.  At tonight's set change I took the reservoir out (35-40u left) and it was full of bubbles including biggish ones.  No wonder insulin was acting like water as I've probably been pumping a mixture of air and insulin.  Anyone any idea where these bubbles come from as they weren't there when I loaded the reservoir?


----------



## SB2015 (Jun 18, 2019)

Hi @Matt Cycle, I have not used that pump, but I am interested in it for the future.  My comments are therefore based on my Combo.  I also end up with bubbles at times, and I can only guess that they come from a leak in the lock.  I was advised to keep my pump with the tubing downwards so that any bubbles go to the top away from where the delivery is.  A bit like priming a pen and then keeping it upright.  I am not sure that that is any help, but I hope that the levels are settling and that the cycle ride went well.


----------



## everydayupsanddowns (Jun 18, 2019)

Good tip from @SB2015 about the angle of the pump in use. 

For me, it’s about bubble reduction rather than elimination, since in the years I’ve been on a pump there always seem to be a few of the pesky blighters!

Partly that is down to filling technique. Ensuring the insulin filling the reservoir is at room temp as a minimum is really important (gas is less soluble in warmer liquids so bubbles emerge as insulin warms up next to the body). It also helps to try to ensure the insulin is aerated as little as possible - I find filling under a slight vacuum helps by only replacing half the air in the vial for the amount filled. 

Oh and tapping, obviously. Lots of tapping!!

This is my basic routine which removes 98% during filling and only leaves some little champagne ones to emerge (and potentially combine) during wear. 

https://www.everydayupsanddowns.co.uk/2015/08/64-days-with-minimed-640g-ep-5-changing.html

But yup... angling the pump so that any bubbles that sneak through don’t get into the tubing is the best tip of all


----------



## Matt Cycle (Jun 18, 2019)

Thanks both.  Yes, it has only been small bubbles, if any, so far and they have obviously haven't had any noticeable impact.  Not sure what caused these larger bubbles to have formed on this last reservoir.  Insulin always at room temp and air always injected down into air space of insulin vial.  I remember only half filling syringes with air when using them so I'll try that next time Mike.  Not sure about having the pump 'upside down' SB as the clip only allows it to have reservoir and tubing pointing up when on a belt.  Things seem more 'normal' tonight so I'm guessing it was a dodgy reservoir or some sort of operator error!


----------



## everydayupsanddowns (Jun 19, 2019)

Matt Cycle said:


> Not sure about having the pump 'upside down' SB as the clip only allows it to have reservoir and tubing pointing up when on a belt.



The Medtronic clip has that hook at the bottom so could theoretically hang downwards I suppose? Personally I’ve always worn mine sideways (to stop hat annoying sticky-up bit digging me in the ribs when I sit down). I use a loop of elastics red fabric, sold originally as a hair band looped around my belt to hook the clip through. Did the same with my Veo too.


----------



## Matt Cycle (Jun 19, 2019)

everydayupsanddowns said:


> The Medtronic clip has that hook at the bottom so could theoretically hang downwards I suppose? Personally I’ve always worn mine sideways (to stop hat annoying sticky-up bit digging me in the ribs when I sit down). I use a loop of elastics red fabric, sold originally as a hair band looped around my belt to hook the clip through. Did the same with my Veo too.
> 
> View attachment 11613



Ah yes it does work Mike.  Would feel a bit weird upside down and there's always the danger if the clip is pressed it would just drop (albeit still hanging by the tube) whereas the correct way round it still rests on the clip hinge if pressed.  Every time I bend to tie my shoelaces in the morning it's a jab in the ribs from that sticking up bit.  Got used to it now. 

Bloods back to normal after reservoir change yesterday which is slightly annoying as I did the Cycle for Cities ride on Monday with high bloods because of that bubble issue.


----------



## HOBIE (Jun 19, 2019)

When filling the reservoir I always hold the pump at a lower level to the reservoir. If any air in the system they go out the top no prob


----------



## everydayupsanddowns (Jun 20, 2019)

Matt Cycle said:


> Bloods back to normal after reservoir change yesterday which is slightly annoying as I did the Cycle for Cities ride on Monday with high bloods because of that bubble issue.



Glad your BGs are back behaving again. Maybe the dodgy reservoir had a leak behind the o-ring seals?

Sometimes it’s very hard to know exactly what went wrong when BGs so all nuts!


----------



## VICTOR HILL (May 9, 2020)

i do  have those little  bubbles in  many years on a combo  13   years  4 pumps al the same model with improvement s
but i do get  veery annoyed like some of  you  say were do they come as i tap tap yap tap    to get air bubbles to go out sometime needs a prime and half   to final get them gone .
and  i like the idea  line at bottom   as any bubbles rise to the top
still biggest problem were to put the needle  s after so long my body has been a pin cushion  but now with pump 3 needles a week    years ago on the pens  4/5times day   ouch   modern improvements   take care keep safe
    c19  may be just around a corner  vic


----------



## Pumper_Sue (May 9, 2020)

Even though this is an old thread, the only pump I have ever had problems with bubbles is the medtronic pump.
If you look at the cartridge carefully you will find there is a design fault regarding the rubber seal. Bottom line it is not airtight hence the bubbles.


----------

