Re: [IPk] Timesulin query
I also experienced a need for a lower basal rate when switching to the Vibe
from the accu Chek combo. Both pumps deliver their basal rates every 3 minutes,
so for me the only difference was the speed of bolus delivery. Just to chip in
on your scientific experiment :-)
> On 14 Mar 2014, at 12:50, "Nanette Freedman" <email @ redacted>
> Interesting speculation.
> An alternative, but equally speculative, speculation might be that the
> more frequent though smaller drips of insulin coming through the
> cannula as a result of the more frequent basal delivery is slowing
> down the clogging.
> Probably this is off only academic interest, but two factors might
> help distinguish between the two conjectures.
> Firstly what are your basal rates - you wrote that you use about
> 18-20u basal a day - 18u a day, if constant basal, would correspond to
> 0.75u/hour, which would be delivered every 3 minutes with a Vibe, and
> with the 522 about every 8-9 minutes (divide the rate into drips of
> 0.1u and give them uniformly distributed over an hour) - so there is a
> difference there.
> Secondly the Vibe has 2 options for bolus delivery - normal (1u every
> second) and slow
> (1u every 5 seconds) - you could test (which you probably don't want
> to do!) if going over to the slow would make a difference.
> But, aside for academic interest, the only other reason for wanting to
> know would be to know what factors are important if/when you need to
> make a choice about another pump.
> Aside from this your comment about clogging and cannula life is
> interesting. Since switching from the Cozmo to the Vibe, I have more
> frequent problems with sets going bad after 1-2 days, instead of
> generally lasting 3 days. I am also using somewhat more insulin. I use
> Humalog, which you write is less prone to clogging than Apidra. I also
> use the same sets (also Comfort). I think basal delivery is identical
> - but I'm not sure because the Vibe gives one those strange warning
> messages when one sets temp basals, saying Minimal basal rate limited
> to 0.025u/hour - sometimes when it is not set to less than that, and I
> wonder if it is really reporting a rounding error, and should be
> saying that you have requested a basal that is not an exact multiple
> of 0.025u/hour, and more than that I want to yell at it and demand
> that it tell me what basal rate it is in fact delivering. But one of
> the few things which is different is bolus delivery - it seems to me
> slower than on the Cozmo, and as a result of your comment I have just
> gone to the setup menu on my Vibe and noticed that it is set to slow -
> had assumed it was normal - now it is - so I can be a guinea pig for
> the test I proposed above and lt you know if I have fewer problems
> with bad sets before 3 days now that I have switched to the faster
> deliver option - let's hope so! and thanks for drawing my attention to
>> On 14 March 2014 14:18, Joel Milner <email @ redacted> wrote:
>> When I was pumping with the 522 I was self-funding CGM on a 24/7 basis using
>> Medtronic Sof-sensors that I was picking up at reduced price from the "grey
>> market" so I have had a good handle on my BGs for several years.
>> TBH the reduction in basal is something I do not really understand and would
>> not have predicted in advance. I am using the same infusion sets (the
>> shorts are identical to the 13 mm Silhouettes). I suppose that the smaller
>> frequent basal deliveries is a possibility.
>> Another explanation (although this is entirely speculation) is that it is
>> connected to the speed of bolus delivery. I have always had problems keeping
>> sets working efficiently. I use a 2-day rotation and with the 522, I often
>> noticed that my CGM trace would be rising on night 2. I hardly ever see this
>> with the Vibe. John Pickup has presented evidence that one of the main
>> site degradation is the denaturation of insulin at and around the cannula
>> by reduced pH. This can cause partial clogging of the cannula and absorption
>> problems. Of the three Analog insulins, Apidra (which I use) is much the
>> prone to this problem. The Vibe delivers boluses very rapidly, whereas MM
>> take geological time to do so. Perhaps the rapidly delivered boluses are
>> to flush the cannula and keep it clear of denatured insulin.
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