Question about poor site absorption

[Dave26]

I'm an Omnipod user, for a bit over a year now. I've read here many times about tubed pump users having poor absorption at a site, pulling the set, and putting in a new one somewhere else.

While I haven't experienced this with a pod, I don't see any reason why it would be different, so I assume this happens to pod users as well sometimes.

Anyway, my question is this: I don't understand the dynamics of a poor absorbing site. People usually "detect" it by rising BG when it shouldn't be. What I don't understand is, what has happened to the insulin? If its not dripping out of the site, it's being absorbed by the body. Where else would it be going?

So, is the dynamic that the inslin is just absorbing slower than "usual"? Doesn't this then imply that there will be other effects downstream, like a longer duration of action, causing unanticipated lows?

Insulin doesn't just disappear. I can't think of any metabolic path for it to enter subcutaneously -- even with poorly absorbing local tissues -- and somehow "bypass" the rest of the body having no effect.

So, what happens? When you have a poor site, with rising BG, change the site and then carry on with pump-drivin IOB calculations only to find yourself battling a low 3 or 4 hours later? Is a bad site almost a guarantee for a roller-coaster day?

[Jen]

My absorption issues are usually related to allergies and my sites getting inflamed. When this happens they get red, itchy, and often have a bump or hive around the insertion site. With the metal sites there will sometimes be a hard lump underneath, which I think might be insulin. Sometimes I happen to notice that a site is bleeding or feels wet or when I bolus I can feel the insulin soak into my pants. Sometimes I've removed a site and had insulin come pouring out (when I hadn't noticed any insulin leaking while it was in). Other times, I agree with you - I have no idea where the insulin goes ...

With most bad sites, though, you are still getting some insulin, so it's not like it's disappearing completely, it's just not working as well as it should. Most of the time if I have a site that's not working well I'll noticed because I'll be stuck around 11-15 for a day without being able to get down. During times I've gotten NO insulin (like if the pump runs out of insulin or becomes unknowingly disconnected) I find myself at 20-25+ within a few hours. The only time I ever end up that high from "just" a bad site is if I have a bad site plus eat a high-carb meal at the same time.

[MarieB]

Here's a discussion you might find interesting
https://forum.tudiabetes.org/topics/scar-tissue-shot

[JohnG]

If Your body makes insulin it delivers it, via the portal vine. A pump delivers insulin into a saturation pool that develops around the infusion site and your blood stream is saturated with insulin until the concentration build up is sufficient enough to satisfy your currant needs, if the body rejects the infusion sight it then attacks the area , absorption is slowed down and in some cases is stopped completely causing a pool of blood and fluid to build up, this is what creates the fluid and blood gusher that comes out when some infusion sets are removed. It's a balancing act and the insulin will only last so long before it is removed via the renal system.