# Failed cannula



## Flower (Feb 26, 2014)

How long do you give yourself if your blood sugars are rising before changing the cannula?

I've had a difficult 24 hours having just come out of hospital after 2 weeks with and infected fractured foot. Home on antibiotics and blood sugar really erratic and endlessly creeping into mid teens.I have been correcting to try and get them stable as well as using TBRs. Changed cannula as the 3 days were up and levels carried on in the mid teens despite my corrections. My sensor started predicting I was going high and I was already at 17.6, corrected again then less than an hour later I was at 24.6. I haven't been that high in years but all the time I was convinced it was from having an infection, it didn't cross my mind it was the cannula as I haven't had a set fail for ages.

I changed everything and corrected and this morning woke up at 2.5. Some days it really is such a challenge. I made a mental note to suspect the cannula next time things start going haywire.


----------



## Redkite (Feb 26, 2014)

Hi Flower,

The protocol we were told to follow for a BG of 14+ (unless you know already that the cannula is the problem!) is:

* check ketones
* if ketones low/zero, take an insulin correction bolus through the pump
* retest BG after 60-90 mins, and if no significant reduction, correct by injection and change cannula
* if ketones >0.5, correct by injection and change cannula

Some people would change their cannula and bolus through that new set, but I always prefer to get some injected insulin going in, so you can be certain (just in case the new cannula also has a problem!).  Also, if my son's levels are excessively high (18+), I would usually go straight to injection and not mess about correcting through the pump and waiting another 60-90 mins, especially at night.


----------



## everydayupsanddowns (Feb 26, 2014)

Ach! Rotten luck to have a cannula fail when you are already struggling with/dealing with a cause of hgh BGs.

I was told the same as Redkite.

Interestingly... syringe or pen corrections often work faster than pump boluses because the units:surface-area ratio is different than in the 'pocket' that builds up around a site in use 24hrs a day for basal and bolus.  

Additionally you can 'superbolus' to get BGs down faster. Effectively you work out how much basal you would have over the next couple of hours and bolus that much, then set a 0% TBR for that many hours.

Personally if I even slightly suspect the set I tend to just massively over-correct (perhaps 2x or 3x the suggested amount) and then wait an hour for BGs to come down then top up with whatever carbs are necessary to deal with the remaining IOB. In the past it has only been when I've done that that I've build up enough pressure in the tubing to trip a 'no delivery' alarm.


----------



## Redkite (Feb 26, 2014)

everydayupsanddowns said:


> Additionally you can 'superbolus' to get BGs down faster. Effectively you work out how much basal you would have over the next couple of hours and bolus that much, then set a 0% TBR for that many hours.
> 
> Personally if I even slightly suspect the set I tend to just massively over-correct (perhaps 2x or 3x the suggested amount) and then wait an hour for BGs to come down then top up with whatever carbs are necessary to deal with the remaining IOB.



 That would be a risky strategy for my son - as he would inevitably not remember the topping up carbs bit!

Gary Scheiner recommended injecting into your calf muscle for a more rapid reduction in BG  Unsurprisingly that doesn't appeal much to my son!!!


----------



## Flower (Feb 26, 2014)

Thanks for the replies, Unfortunately I didnt have any ketone strips for my meter so have put that right today. I am always scared of over correcting which in the end I managed to do waking with a 2.5. Its difficult to know when to try something else, my pump was showing 4 units active insulin which is way more than I have in one go and the last thing I wanted to do was inject although I know it does reduce my bgs faster - especially in my calf Ouch!! Has anyone other than Gary Scheiner ever resorted to this?


----------



## Annette (Feb 27, 2014)

Flower said:


> Thanks for the replies, Unfortunately I didnt have any ketone strips for my meter so have put that right today. I am always scared of over correcting which in the end I managed to do waking with a 2.5. Its difficult to know when to try something else, my pump was showing 4 units active insulin which is way more than I have in one go and the last thing I wanted to do was inject although I know it does reduce my bgs faster - especially in my calf Ouch!! Has anyone other than Gary Scheiner ever resorted to this?



I did it a few times when I was a kid, but then was told in no uncertain terms by the staff on a diabetic childrens holiday that I should never do that as it was going straight into muscle and therefore had a totally different action profile. I've never done it since (and it did hurt more at the time, I seem to remember).


----------



## Redkite (Feb 27, 2014)

Annette Anderson said:


> I did it a few times when I was a kid, but then was told in no uncertain terms by the staff on a diabetic childrens holiday that I should never do that as it was going straight into muscle and therefore had a totally different action profile. I've never done it since (and it did hurt more at the time, I seem to remember).



I think that's the whole point.  Gary advocates it as a way to reduce high levels FAST - especially if you're going to be exercising, ie. using that muscle!  The insulin would absorb very quickly indeed.  He is type 1 himself as well as being a Certified Diabetes Educator, so his advice works "in the field", whereas many health professionals simply don't have that level of knowledge, and also they have to be careful endorsing radical/experimental approaches because not all patients would be knowledgeable or diligent enough to follow up the calf injection with appropriate BG monitoring etc.


----------



## heasandford (Feb 27, 2014)

wow, this is a great reminder of the protocols as well as suggestions for bringing down highs. 

I am constantly reminded how slow the absorption of insulin is compared to what it should be, but then how effective it is when it does get there, resulting in a hypo! Also the variability in absorption rates - has anyone ever monitored results from a new cannula compared to 2/3 days later? As a newish pump user I am still getting tremendous variations which I haven't solved - and may never, since that was the 'pattern' before! 

As always this online community continues to inspire and support!


----------



## Redkite (Feb 27, 2014)

heasandford said:


> Also the variability in absorption rates - has anyone ever monitored results from a new cannula compared to 2/3 days later?



Yes!  At first I didn't see the "pattern" because there are so many other causes for variability.  But at some point we started doing set changes on regular days of the week for convenience, Tues, Thurs and Sat, so that each week two cannulas were in for 2 days and one was in for 3 days.  After a couple of months, it became extremely obvious that on day 3 his levels were ALWAYS higher.  Something was obviously going on in the tissues around the cannula site which meant absorption deteriorated after 48 hours.  We now change the cannula every 2 days.  If it gets accidentally left in for a third day, his BGs always go up.


----------



## everydayupsanddowns (Feb 27, 2014)

Sometimes I think I might be seeing a pattern like that... but it doesn;t seem to be repeatable enough for me to act on it.

I thought I was getting highs for the first meal after a set-change recently (2 or 3 on the trot misbehaved) but then today's change went without a hitch.

Good that you've found a way to avoid those dodgy days Redkite


----------



## AJLang (Feb 27, 2014)

I have this when the absorption changes but for me it can be in less than 2 days.  For example today BGs have been 8-11 despite corrections and all I've eaten is soup but yesterday, with a new cannula, they were normal ie 4-6. I've just  changed my cannula and based on previous experiences my BG will be back to 6's within two hours. However, as discussed before I'm doing very well if a cannula lasts me two days and I've been advised to change them daily. My complete cannula failure the other day was when I tried to make it last three days


----------



## Hanmillmum (Feb 27, 2014)

Regarding patterns and cannula changes Millie was always prone to have a hypo after a change regardless of time of day etc etc I usually try to change cannulas before a bolus is due so I factor that issue in now and have to take a chunk of the bolus off to avoid this hypo. I wonder if this is the same for others?
Possibly due to steel cannulas and therefore changing every other day have not seen any high patterns.


----------



## heasandford (Feb 27, 2014)

I realise that the software for the Accuchek pump has an 'insulin Effect' graph that allows me to see whether there is a pattern between cannula changes as they are shown as 'pump stopped'. I don't apper to have any recogniseable effect, other than completely random peaks and troughs!


----------

