Cannula clog?

Minimed pump, suret site, humalog insulin. I know that insulin can crystallize in pump tubing and cause a blockage. Here’s what I don’t know:

Why would this happen some days but not others?

Is it visible? After a high with no other known cause I’ve changed my daughter’s site and seen that a small area directly coming out of the reservoir section is more opaque than the rest of the tubing (the same section is clear in a new tube).

If it’s not a visable problem, how would we even troubleshoot it?

Thanks for any info you have!

I’ve only used the metal tipped Suret sets once(I use the Silhouette and Quickset), so this is a semi-educated opinion. When you see opaque in the the Silhouette and Suret tubing that is normally a bubble. It is very unlikely that your insulin would ever crystallize in the tubing since basal insulin is always flowing through it.

When you change sets be very sure you don’t have bubbles in the reservoir. Champagne sized bubbles are fine, but any larger and you need to get them out before you connect the set.

Does she need the metal set? You can call Medtronics and they’ll send you a sample of any of their other sets you want to try. Keep in mind that the Quickset and Silhouette sets have inserters you buy separately.

I concur with @KevinH that the opaque area you are seeing in tubing is most probably an air bubble. Do a double check before placing the newly filled reservoir in the pump; hold it up to a background light and slowly tip it back and forth a couple of times.

A few years ago, a number of persons with T1 for more than 50 years did an informal survey about insulin crystalizing in cannula and tubing. It was observed that Humalog has a tendency to crystalize under certain conditions. It is thought that Novolog may be better in pumps until something better comes along.

Note that Novolog and Humalog, although having similar effective times in most people, are not identical - so consult your diabetes professional before making any switch. Novolog is aspart and Humalog is lispro - both of recombinant DNA origin.

So I am definitely careful about bubbles in the resevoir and she has a metal needle. The opaque bit is stationary so I’m not thinking air. I just can’t find a reason for her day three highs.

If the “highs” fall regularly on the third day, and not other times it could be that her site is seizing up and insulin is not being properly absorbed.

A different type infusion set may be worth a try. I’ve always used the “quick set” with soft cannula and really haven’t had troubles except a very occasional jarring loose from unusual actions on my part.

This sounds like a definite possibility. What is seizing up exactly? We’ve used soft cannula before. I think I’m using the term cannula wrong. I should have posted “tubing clog”? :grin: I also wasn’t clear about the days. We change every other day. It’s not the majority of the time but days like today it was definitive that she wasn’t receiving insulin. Just couldn’t figure out why. As soon as we changed her site it was fine.

I have had trouble with clogging. Had BG’s at 600 for no reason so I bolus. After two hours I check again its at 590. Bolus again. Another two hours, no change in BG. Change my site and WHAMO! All the built up insulin suddenly breaks free and I drop to 40 in two hours. Then you can’t eat enough Pop-Tarts to keep up. Finally you get somewhat back to normal and you have Diabetes Hangover. I hate Diabetes Hangovers!!!