Insulin pump question

I have been wondering how low you can let the insulin in your pump get before you actually have to change the infusion? When mine gets down to 17 units, i start freaking out! Is it safe to let it get to 10 units before you change? I guess I am assuming that the amount of insulin left is accounting for what is in the tubing? Is that incorrect?

My endo has reamed me out because I let my pump run completely empty before changing the cartridge. He said it should never get to zero. So I've been trying to change it when it's between 1-5 units left (or more if I'm going to be leaving the house for the day), but it still doesn't always happen.

I'm pretty sure the insulin left is only that left in the cartridge, based on the position of the motor. But when the motor hits the end, it can't move any further, so it can't pump the insulin out of the tubing. It's probably bad, but once when my pump was empty and I had no refill I filled the cartridge with a bit of air to tide me over until I got home. That way it pumped out the remaining insulin in the tubing (I use the longest tubing so there's about 20 units in there). I am sure my endo would freak out if he knew I did this, but I've only done it once and would only do it in extreme situations!

Jen, if i am at home i do that quite frequently. the pump says empty but there is still insulin left and i have never gone high because of that. i always carry a pen with me, so if there is no insulin left i can even change my reservoir on the way, out and about. sometimes i just forget it, or i am too lazy to do it.
anyway, nothing bad has happened to me, i was never at that point that my pump did not deliver any insulin at all.
so in my opinion, if you have the stuff with you, let the pump run down to zero, otherwise change if you leave the house.

I've run down to zero and checked when I'm changing it and it will still have droplets at the end of the infusion set. I usually try to get down to around 5-7U left, sometimes less, because I hate wasting drugs.

The amount of insulin that the pump displays does not include the insulin in the tube. I've worn pumps since the '80s and I've never seen any difference in delivery performance until the pump gets to 0 units and alarms. That being said, sometimes sites become "stale" and insulin absorption slows. In that case change sites ASAP, without regard to insulin wasted. It's not worth it.

I always carry infusion set change gear with me but I try and time my set changes to when they're convenient. If the number of units left in my pump will expire when I'm due to be sleeping or in the middle of a social evening that I don't want interrupted, then I change in advance and waste a few units of insulin. I have my low insulin alarm set for 20 units, which is a 1/2 day supply for me.

I've also used insulin left in the tube when my reservoir empties, as Jen describes, and I don't have any other options. It's an emergency tactic that does work but I would be extra vigilant with glucose monitoring. Sometimes you just have to do what needs to be done. And don't forget your back-up supplies next time!

Wow! I have been throwing away a lot of insulin each time. I change my infusion every 3 days like clockwork, regardless of what I have left in the cartridge. Sounds like i need to decrease the amount i put in a cartridge so i can make the most of my 3 days. Thanks for the comments and help! If i every get close to zero, at least now I won't have a heart attack!! lol

Keep in mind that your infusion set and reservor do not have to be changed at the same time. Infusion sets are best changed ever 48 to 72 hours to avoid infections etc. Some folks use reservor for four or five days until it is empty. My reservors last about 2 days so I changed both at same time rarely until a few months ago when I started having issues with sites. Now change both at same time. I rarely waste insulin. Only do so when I do not have enough to get through the night.

I have no idea what the issue would be with a zero reading before changing the pump supplies. Mine runs out most of the time because I don't like to waste insulin as it is too expensive to treat it like water.
I have mine set to alarm at 5 units left. Of course, at zero there are still at least 10 units more in the syringe. I let it run out; it alarms; I change it. Now if it is late at night and I want to go to sleep, I will change it with a few units left. Or if I need to leave the house and know it will run out shortly anyway, I change it. That is what I do; I am not suggesting what anyone else should do.

When yours gets to 17 units, you still have 27 units in the syringe.

I think the "10 units left" thing depends on the pump. When my Cozmo ran out, it had 10-15 units left still, so I frequently would just leave it another few hours. When my Animas runs out, it's truly empty and if I leave it my blood sugar rises. I'm not sure about other pumps like Minimed, OmniPod, Accu-Chek, T:Slim ...

I use a medtronic 523, and there is usually about 10 or so units left when the pump reads zero. So if I'm going to bed and I've only got,say, 6 units left, I leave the change until the morning.

Also, if I've only got 30 units left in the morning, I can usually get through the day without changing until dinner.

But...and this is a big BUT...I'm T2 (we think...long story) and I tend not to get ketones, and the insulin doesn't usually freak out on me. Obviously I do change it sooner if I see my numbers going up.


Interesting discussion, and one of those things that is dramatically different between the Omnipod and tubed pumps.

With the pod, I always use every last drop of insulin. Including the little "extra" not accounted for by the pump itself (intentional, I'm sure), 1.5-2U.

I run it out until it alarms that it's completely empty, then change it. Since there's no tubing holding anything, it all gets used.

Insulin's expensive!

That being said, sometimes sites become "stale" and insulin absorption slows. In that case change sites ASAP, without regard to insulin wasted. It's not worth it.
And there's the glaring disadvantage of the Omnipod right there -- no separate infusion set, so if a site is bad for some reason, the entire pump get's discarded.

In cases where the pod has to be removed and discarded before all insulin has been used, insulin can be removed from the pod and reused in a new one, but there always seems to be 10-20U that simply can't be removed from the 200U reservoir.