User error

[everydayupsanddowns]

Just a quick heads-up and confession.

A few days ago I made a small tweak to my correction ratio (my insulin sensitivity has been rolling with the seasons). I had felt that occasionally the corrections the tSlim was making were slightly over-reaching, so wanted to soften things a little.

So I pushed it from 1u:3.8mmol/L to 1u:4mmol/L. Or that was my plan…

Over the next 2 days I had some real clanging hypos, which is unusual for me, and I was checking back through pump history to try to work out what on earth was going on.

Well it transpires that for one lunchtime-afternoon slot I had set 1u:0.4 rather than 1:4 😱

And wouldn’t you know it… if the pump delivers 5u as a correction, where you really only need a 0.5u nudge, it has dramatic consequences!

I’m slightly surprised the pump didn’t give me a ARE YOU SURE? warning with one slot 10x different to all the others (as it has in the past when trying to set very weak ratios overnight).

But yes. Always pays to double check the changes you are making!

 

[Pumper_Sue]

Glad you sorted it and no harm done.

 

[Rob Oldfield]

Interesting point. One of the key points when designing computer systems should be to ensure that users are warned/blocked from doing things that look iffy. And with a pump the potential downside to a mistake could be critical.

Certainly though, one of the critical issues would be how to pop that warning up. With a computer screen, or even a mobile, there's a good amount of space to pop up an decent explanation about what has triggered the alert, but the smaller amount of space on a pump is clearly going to limit that.

 

[Bruce Stephens]

One of the key points when designing computer systems should be to ensure that users are warned/blocked from doing things that look iffy.

Yes, which is one of the big lessons from safety in flying planes: when pilots (or other staff) make errors, it's an opportunity to at least look at whatever lead to them making those errors. It's not always human error, often something about the overall system needs fixing.

 

[Sally71]

Oops! Good job you worked it out fairly quickly!
When my daughter went onto the T-slim and we had to copy all the basal information over from her old pump, somehow we managed to get one of the basal time periods wrong by a fairly significant amount (although perhaps not quite as significant as yours!). Amazingly it didn’t seem to make much difference, I only noticed because I keep a note of the daily basal total (just in case pump fails and we have to go back to injections, which has never yet happened fingers crossed) and wondered why it didn’t match when I made a small change a few days later and updated my notes. When we were entering the basal into the pump at the beginning we immediately got a warning because there’s quite a big step between some of the time periods, so I am surprised that you didn’t get one with one correction amount so much different!

 

[nonethewiser]

Own pump has ability to set max dose to be delivered, maybe double check in settings that yours is activated.

 

[Inka]

Scary! I hope your hypos weren’t too bad.

 

[SB2015]

Oops!!! Glad that you spotted the error and hope that the hypos were manageable.

 

[everydayupsanddowns]

When we were entering the basal into the pump at the beginning we immediately got a warning because there’s quite a big step between some of the time periods, so I am surprised that you didn’t get one with one correction amount so much different!

Own pump has ability to set max dose to be delivered, maybe double check in settings that yours is activated.

Yes I do get alerts, for all sorts of things, including (when using Basal IQ) a particularly annoying and repeating one when trying to set a 0% TBR, which is an exercise strategy I got used to using while on the MM640G.

I’ve just tried it again though, and for correction factors it happily accepts anything from

1u:0.1mmol/L
to
1u:30mmol/L

with no alerts or warnings based on other sectors of the same pattern.

Which does seem pretty dangerous tbh.

I will drop Tandem a line, and make sure they are aware of it, possibly even “yellow card” it?