Okay, this is bugging me
Jan. 27th, 2010 07:19 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
firefly124Today's the med math test. Originally, it was scheduled for our first day back, but someone took pity on us and moved it to today. The primary impact of this is that everyone's had even more time to get all worked up over it.
A classmate brought a question to me yesterday from a "brain buster" sheet. The nursing tutor who handed out said sheet didn't even know how to solve it. I'm actually reasonably sure it's not solvable as written.
An unspecified med is 0.02% strength. How many grams per 100 mL? Per 1 mL?
First, a percentage means nothing without more information. It has to be a percentage of something. But no matter, let's assume it's percent by mass, which means mass of solute/mass of solution. That's a fairly standard measure Blowing away the decimals for ease of calculation, that gives 2g of drug per 10,000g of solution. Now to convert it to grams per milliliter.
Oh, wait. There's no density. There's no way to look up a density, as the med isn't specified. There is no way to convert a pure mass measurement without some way of figuring out the relationship between mass and volume, and they haven't given one.
So let's try percent by volume. Still doesn't work, because then we've got a strictly volumetric measurement and no way to bring in mass.
Finally, I said, "Well, let's assume for the sake of being able to find an answer that, in defiance of all rules of math and units of measure, they mean .02% to convey 2g/10,000 mL." That gives .02g/100mL and .002g/1mL . Except the assumption being made at the start makes no sense whatsoever. If there's a convention in dosage calculation that involves percentages conveying a mass-to-volume relationship, I've not found it anywhere.
Um, so hopefully no questions like that on the test, or no more than two. Need a 90% to pass, after all.
A classmate brought a question to me yesterday from a "brain buster" sheet. The nursing tutor who handed out said sheet didn't even know how to solve it. I'm actually reasonably sure it's not solvable as written.
An unspecified med is 0.02% strength. How many grams per 100 mL? Per 1 mL?
First, a percentage means nothing without more information. It has to be a percentage of something. But no matter, let's assume it's percent by mass, which means mass of solute/mass of solution. That's a fairly standard measure Blowing away the decimals for ease of calculation, that gives 2g of drug per 10,000g of solution. Now to convert it to grams per milliliter.
Oh, wait. There's no density. There's no way to look up a density, as the med isn't specified. There is no way to convert a pure mass measurement without some way of figuring out the relationship between mass and volume, and they haven't given one.
So let's try percent by volume. Still doesn't work, because then we've got a strictly volumetric measurement and no way to bring in mass.
Finally, I said, "Well, let's assume for the sake of being able to find an answer that, in defiance of all rules of math and units of measure, they mean .02% to convey 2g/10,000 mL." That gives .02g/100mL and .002g/1mL . Except the assumption being made at the start makes no sense whatsoever. If there's a convention in dosage calculation that involves percentages conveying a mass-to-volume relationship, I've not found it anywhere.
Um, so hopefully no questions like that on the test, or no more than two. Need a 90% to pass, after all.
