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[IP] Canula volume revisited

Michael responded to Bob:

 The instruction sheet(s) which I have for the Tenders and the Comfort sets
> both indicate that a .5 unit bolus should be administered to fill the
> Is the Silhouette using a different diameter cannula, hence the requirement
> for more insulin to "prime" the cannula?

The amount required to fill the canula tube and the amount required 
to bolus on a 're-connect' are different.

The 0.5 unit bolus is to make up for the small amount of air drawn 
back into the tube attached to the pump. 
The canula attached to you is sealed by it's own plug on either a 
sof-set or comfort set(or equiv).


Bob and I were referring to the amount needed to fill the canula when
inserting a new one, not to a small "priming" bolus to be given after being
disconnected for awhile.  He and I have both traditionally bolused .4 or .5
units to initially fill the canula, both having good success with this amount.
However, after I "tested" the volume of the canula to be exactly 1.0 unit, I
decided to see what happened if I used 1.0 unit to do the initial "filling". I
went LOW!  I am confused by this somewhat, and will try to measure the volume
of the canula again.  I'm not convinced that the volume is really 1.0 unit,
and don't recommend that others go around giving themselves a 1.0 unit bolus
to fill their canulas.  Or, if the canula really does hold 1.0 unit, then
perhaps there is some other physiology going on with the initial filling.  

Mary Jean


I was interested in the volume of the canula because if you inject 
humalog through it, you have to follow it with enough regular from 
the pump to push all the humalog in or it will not take effect.

Telling the difference between 0.5 and 0.7 units would be tough with 
the kind of experiment I suggested. +or - 0.5 units is probably a 
pretty good measurement.

I wonder if the MiniMed answer is the 'volume' of the empty canula??
Your measurement sound like it was right on.

Anyway, 1 unit is a nice easy number to remember for a follow up 
bolus after and injection of H in the Comfort-Set

Insulin-Pumpers website   http://www.bizsystems.com/Diabetes/