[Previous Months][Date Index][Thread Index][Join - Register][Login]
[Message Prev][Message Next][Thread Prev][Thread Next]

[IP] Re: curious phenomenon

Sam, John and I had a discussion about this a few months back, and I went
out and actually measured the distensibility of the tubing.  It turns out
that there's really not much distensibility in the tubing at all.  If you
have a bubble in the syringe then this too can be compressed a bit, but
even here unless the bubble is biggish, there isn't too much of a problem.
Remember that a full inch of tubing is only about 0.4 U, so a few mm
movement of the air meniscus is not much of a problem.   AND although you
can see more movemnet of a bubble when you raise the tubing end above your
head, no one does that when the insert or connect.  So not to worry, as
long as you don't have big bubbles in the syringe.

<<<<<<<From: Sam Skopp <email @ redacted>
I have discovered a curious phenomena when priming the pump. If the
quick-disconnect end of the tubing for the Silhouette is held low it seems
to fill rapidly... but when you raise it up much higher than the pump, the
drop at the end of the needle diappears... priming a bit more then brings
it back. I wonder if some reports of highs after doing a new set might be
due to falsely thinking that the set had been fully primed, when in reality
it had not.

My unscientific guess is that holding the quick-disconnect end of the
tubing higher than the pump while it is priming, forces it to push more
insulin into the tubing and equalizes the pressure better. Can anyone else
verify this? I'd also wonder how to tell whether doing it this way really
makes a difference? I've been using this technique for the last 6 weeks and
haven't had a problem with highs after inserting a new set since... but
then, as usual, YMMV.


Wayne Mitzner
Department of Environmental Health Sciences
The Johns Hopkins University
615 N. Wolfe St.,  Baltimore, MD 21205
Tel. 410 614 5446,   Fax 410 955 0299

Insulin-Pumpers website http://www.insulin-pumpers.org/