[Meta] proposal — a flair for dead space posts
proposal — a flair for dead space posts. This affects how posts get sorted and removed, so it belongs in the open.
Reconstituted at 3mL when I meant to use a different volume. Caught it because the units looked wrong on the barrel. Now I write 6.67mg/mL on the glass before I put the cap back.
If your calculation produces a fraction of a unit, the concentration is wrong for your dose. Change the water volume until the numbers land on whole units.
Shook the first vial because nobody told me not to. It was fine, but I have swirled every one since.
Would rather be corrected in public than confident in private.
best — the order this archive was captured in
The failure modes I have actually seen posted here, in order of frequency.
One: reconstituting at a different volume than intended and not writing it down, so the next draw is based on a remembered concentration. Two: treating units as a dose rather than a volume, which breaks the moment the concentration changes. Three: assuming a syringe is U-100 when it is not.
All three are solved by the same two habits — do the arithmetic before the water goes in, and write the result on the glass. Neither costs anything and between them they cover almost every question this board gets.
Agreed on the swirl. There is no reason to shake it and a good reason not to.
I keep a laminated card in the drawer with the arithmetic on it. Looks ridiculous. Has never once let me draw the wrong volume.
bacteriostatic water has the preservative, sterile water does not
more water is not more drug, it is the same drug in a bigger volume
if the maths gives you a fraction of a unit, change the concentration
if the maths gives you a fraction of a unit, change the concentration
Right, and the arithmetic behind it: 5mg in 3mL is 1.67mg/mL, so 1mg is 60 units.
Asked WWB what volume they reconstitute to for their own stability testing and they answered in one line. Useful thing to know.
Asked WWB what volume they reconstitute to for their own stability testing and they answered in one line.
ilias_cabrera has the units point exactly right. They are a volume on the barrel and nothing else.
ilias_cabrera has the units point exactly right.
This is the sentence that makes the rest unnecessary. Write it on the vial and the problem is gone.
reconstituting at a round concentration makes every later dose easy
Agreed on the swirl.
Adding one thing — put the date on the label too. Concentration plus date and you can never mix two vials up.
Small fix — a U-100 syringe is 100 units per mL. If yours is marked differently it is not U-100 and the whole calculation changes.
Wrote the date on the vial as well as the concentration after losing track of which one was opened first.
The dead space question sent me down a rabbit hole for a week. It is a fraction of a unit and it is the same every draw.
a U-100 syringe reads 100 units to the millilitre, every time
- 1Agreed on the swirl. There is no reason to shake it and a good reason not to.15 comments in this branch · started by u/emil_wojcik