could it be that the motor of the tslim emits more heat than the medtronic one? could make sense in relation to the color screen, etc. that is the only explanation i could come up with, however, it’s not a solution. maybe there is a way of measuring temperature in the cartridge place, or ask a pump rep whether this is true? really interesting problem
@tiaE - Yes, I have tried different infusion set types.
@swisschocolate - That is one of my current “top ten” theories. However, the reps and tech support tell me that the tSlim has a temp monitor and alarm if it gets too hot.
Still doesn’t explain why some people are getting 6 days and I (and others as well apparently) are only getting 3ish days. All with the same pump and insulin and infusion sets.
In the four months I have been using the tSlim, I have reverted back to using my Medtronic twice. Both times I have gotten 6+ days with no issues.
It truly baffles me.
I think I read somewhere is that it might be the heat generated from charging the pump.
I currently use each Animas Ping reservoir for about 8’days. I will be considering the t:slim when I pump-shop in the fall, but I would hate to have to start changing reservoirs every 3 days. But it is odd in that everyone doesn’t have the problem.
From my personal experience, the pump gets quite hot when charging. I was told this is normal by reps and tech support. Again, if it gets too hot the temp alarm is suppose to sound.
However, the previous three-day cycle I just went through, I did not charge the battery to test this specific scenario and the insulin still seemed to “go bad” after three days.
Maybe the pump is made not to exceed a temperature that would damage insulin over 3 days. So if the insulin is exposed to the heat for 3 days it is ok, but 6 days would be too much.
It is the quantity that makes the poison after all.
Last year I switched (temporarily, alas) from Medtronic to Assante Snap, which uses pre-filled humalog cartridges. The system was designed to have you go six-seven days on a single cartridge, though you were still supposed to shift infusions sites every three days (they actually had two different kinds of sets to accommodate this). To me this was a huge factor in making the switch, so I asked why I couldn’t just do that with my existing pump. I was told that the reason standard pumps couldn’t do this was because the plastic in the reservoir interacts with the insulin and causes it to degrade faster. The cartridges are made of glass, just like an insulin vial, which is inert so doesn’t have this effect. In fact the cartridges are the same ones used in pen injectors which of course you can keep using until they’re empty–I’d get a couple of weeks on 'em when I was on MDI.
Of course all these rules may differ from what actually happens in practice. Sheer guess, but what you’re seeing may be something to do with the different formulations for the plastic between different manufacturers. I’m back on my Medtronic, but haven’t tried going past three days. My concern would be more about developing scar tissue. I only switched to a pump 3 years ago but I’ve read enough about people running out of “real estate” because of scarring that I just don’t want to go there. YDMV of course but for me that concern outweighs the inconvenience.
@swisschocolate - agreed, this is currently part of my thinking.
@DrBB - agreed, the differences in “plastic” has always been at the back of my mind. You would think though that if NovoLog is suppose to last 6 days in a plastic pump then the FDA would make them make it last 6 days. But, I digress.
I too worry about scar tissue. But, I do change my site more frequent than my reservoirs.
You say that you were on the Assante temporarily and then went back to the Medtronic. Did you have to return the Assante? If so, how did that go?
I am really thinking that I am going to quit the tSlim and go back to the Medtronic. But, I highly doubt Tandem is going to refund my money after 4 months and them saying that their pump works the way it is designed to work.
Thanks!
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Didn’t have to–I still have it.
The thing was, my Medtronic was (is) still under warranty when I made the switch, and the cost of the Asante was quite cheap–ended up paying a $50 co-pay, but that’s nothing compared to buying a pump totally out-of-pocket. So I kept the Medtronic and went back to it when Asante cratered. I still have the Asante and enough stuff that I could use it as a back-up if my primary pump fails for some reason.
That is pretty much exactly what I am thinking of doing with the tSlim and Medtronic.
Go back on my Medtronic and just use the tSlim as a CGM reader. Then, if something catastrophic happens to the Medtronic, I could use the tSlim as an insulin pump.
If I were to return or exchange the tSlim (which I am not sure they would even do at this point) I would still have to buy a CGM reader. Keeping the tSlim as the CGM reader and the knowledge knowing I could use it as a back-up pump might be easier/cheaper in the long run.
Thanks!
I’m not understanding what you mean when you say that you would need to get a “CGM reader.” Is this a Medtronic CGM thing, because I’ve never heard of needing a “CGM reader” for a Dexcom CGM?
Maybe I am not using the correct wording.
With the Dexcom G4 CGM you need some sort of device to show you the blood sugar levels and trending graph that the CGM is producing.
People have called that a receiver/reader.
With Dexcom, I know of two devices that act as a receiver/reader - (1) an integrated pump like the tSlim I am using or (2) the dedicated Dexcom CGM receiver/reader device. If you are using a G5 I believe you can use a smartphone as the receiver/reader.
If I decide to go back to my Medtronic, I would need #2 since my Medtronic is not an integrated pump that is compatible with the Dexcom CGM.
It does seem like you could continue to use the tSlim as the receiver for your G4 and save the not inconsiderable expense of purchasing a receiver from Dexcom. Switching to G5 doesn’t necessarily entail getting a new receiver–you can just use the smart phone exclusively–though I find I have enough Bluetooth dropouts that it’s convenient having both (I use an upgraded G4 Share receiver). The only difference between G4 & G5 otherwise is the transmitter; the sensors are the same.
FWIW, I use a G5 CGM and a Medtronic pump; integration isn’t really that big a deal for me.
Thanks for the confirmation, DrBB.
I appreciate all the info that everyone has provided over the past couple of days, but it really still does not get to the heart of my original issue:
Why can some people use their tSlim cartridge for 6 days and others can only use it for 2-4 days? It is really this inconsistency and waste that I have issue with. And, to be honest, anything that provides consistency with Diabetes is a good thing in my opinion.
I get it though, there are people that love their Tandem pumps and there are people that have major issues with their Medtronic pumps. Its such a personal issue.
I just believe an electronic device should work the same for every single user who uses that device. But, we all know that is not the case.
Thanks again!
Like everything with diabetes it seems to be very individualized. On my Medtronic, I can get about 4 days of use, and even if I still have insulin in the reservoir my blood glucose levels just start running a bit higher. I’m curious to see how my new Tslim will compare. I should get it Thursday this week.
With your 4 days of use on your reservoir, does that include changing your infusion site on day 3? Or, do you change your infusion site with the reservoir on day 4? Just curious.
Good luck with your new pump!
I change my infusion site when i change my reservoir. But 4 has always been about as long as I can make it last without just starting to see higher numbers. Thanks, I’m excited to get it. Haha sad it’s about as exciting as getting a new iPhone. Should be here tomorrow.
Does anyone use the same infusion site for more than 3 days? I understand it may cause infection and adhesive may not stick as well etc but I am just curious. Thanks!
I’ve made my infusion set last up to 4 days…no problem with infection biggest issue is just the adhesive coming loose, and losing its stickiness. That and for me, by that 4th day numbers are starting to creep up some.
Do Not Do This At Home!! I’ve gotten a week out of quite a few sets. My skin holds onto the adhesive like super glue so I don’t have any problems in the area. After day four, though, I am prepared to change my site whenever/where ever needed if my numbers start to creep up. Also, at any sign of irritation I’ll change it. Again, this is not recommended and I do this knowing and understanding the risks.
Oh, and I use the contact detach sets, so sometimes I leave the anchor be and move the needle. I just have to use a good piece of medical tape to re-attach it.
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LOL there are a LOT of things diabetics end up doing that isn’t recommended. LOL when I was still on MDI, I’d reuse the same needle during the entire time I was using a particular pen. Change the needle when the pen was out. Never use alcohol, even on my site changes. Yes like you said, you know the risks, but in 30 plus years I’ve never had any problems with infections from reusing needles or not using alcohol. I reuse the same lancet too.