This website and blog does not provide medical advice, diagnosis or treatment. Read full disclaimer.
I use the Medtronic MiniMed 670G Insulin Pump and mostly use its automated feature. It connects to the Guardian CGM and automatically adjusts my basal insulin to keep my blood glucose at a good level.
My insulin needs change based on lots of factors, and there are some days where my blood glucose trends higher despite the Insulin Pump’s smart algorithms. It seems that the insulin is just not working as well.
On days like these, my insulin to carb ratio also seems too low, and I have to give bigger bolus amounts for the food I eat.
What’s going on when this happens?
The answer is not always the same. There are truly so many possibilities! If the insulin seems like it’s “not working” or “you’re staying high no matter what” then the consideration has to include whether there’s a problem with the insulin, the infusion set, or whether you actually need more insulin.
Here’s a list of what I now consider when I get this issue:
- Infusion set may not be working correctly. This is the most common the answer if the infusion set was recently changed. By “recent” I mean within the last 6 hours or so. I’ve experienced a bent cannula and have found that it can take awhile for the issue to really become obvious. I’ve changed my infusion set at 8am and didn’t realize until 2pm that there was an issue. I think this is because I was still getting some insulin so although my blood sugar was trending high, it wasn’t high enough to immediately suspect a technical issue — the high could easily be explained from miscounting carbohydrates, for example.
- Insulin has gone bad. With my insulin pump, I am supposed to change the insulin reservoir every 3 days because insulin degrades in plastic and also while exposed to higher temperatures. (The body temperature is 98.6 and depending on how you wear your insulin pump and the weather, it may get quite warm.) It is tempting to keep insulin in the pump longer, but it degrades gradually and may lose effectiveness. The insulin may still work, but not as well.
- Infection / Sickness causing increased insulin need. I’ve been told that a urinary infection may cause this. I’ve also read that sickness usually requires more insulin and also that some medications like steroids can cause higher insulin requirements.
- Time of the Month (Hormonal changes). This is particular to women. The menstrual cycle can effect insulin sensitivity. The biggest change I see is an increased need for insulin right before my period and then not needing as much insulin during the first few days of my cycle.
- Stress Even good events can cause stress! I personally see an increased need for insulin when I am doing stressful things like public speaking. The stress hormone, adrenaline, effects blood glucose needs.
How Adrenaline Affects Your Blood Sugar – Adrenaline is the hormone responsible for the “fight or flight” stress response. It has many effects on the body’s systems, including increasing blood glucose.
Infusion Set Failure – A Cause for Unexplained High Glucoses (UHGs) on a Pump.