Sunday, March 4, 2018

Another quick example of the main Libre problem: thermal compensation.

Apologies for not keeping up with the blog, real life has been interfering...

That being said, here is another example of the main drawback of the Libre: thermal compensation is really poor.

Have a look at the chart below and try to guess what it shows...

I am wearing the patch. I am a non diabetic person (neither Type 1, nor Type 2).

12:00: small meal

13:00: exercise (stationary bike starts)

14:00: bottle of sports drink as I start feeling the lack of supplies.

15:00: exercise stops, feeling really drained. My Garmin Fenix says I'll need 67 hours of recovery. My average heart rate was 142, with several spikes to my maximum FC. So far, so good, 61 might be a bit on the lowish side, but nothing incoherent.

15: 30: I do not eat or drink anything and decide to relax in a warm bath for a while...

My BG starts to climb steadily, first spot check is at 105 mg/dL, second spot check is at 157 mg/dL, around 250% of my actual value. As soon as I get out of my bath, my BG starts to drop precipitously (the reader refuses to provide values at that point) and then resumes cruising at the pre-bath value.

What if I had had to take an insulin dosing decision during that time? What if I had an AP running?

Abbott needs to fix this in the future. Fancy apps, not so much. Decent temperature compensation, yes, definitely.

On the "plus" side, at least for Abbott, the combined effect of the sub-optimal (cough, cough) temperature compensation and the delay compensation - the actual smoothed value never reached the projected high - is so bad that I stopped being motivated in reversing it long ago...




1 comment:

  1. I recognize it every morning when I have been in the shower, the actual measurements are way higher than plausible. The algorithm seems to know it, because the curve gets flattend out (still a bit of a rise).

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